Fix Select and grouping bugs

- Deep copy the grouping structure on query copy.
  It is mutable but we have neglected doing this right until now.
- Fix a bug in the previous commit where the last constructed Query.Model was shared between all instances.
- Fix a bug in the previous commit where the query string instead of the query tree was reset when a new select
  expression is set.
- Don't use deprecated method.
- Clean up Javadoc and formatting.

114 files changed, 1482 insertions, 304 deletions

diff --git a/container-search/src/main/java/com/yahoo/search/grouping/Continuation.java b/container-search/src/main/java/com/yahoo/search/grouping/Continuation.java
index eda2b449fda..d7ee3fedfc9 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/Continuation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/Continuation.java
@@ -21,4 +21,8 @@ public abstract class Continuation {
     public static Continuation fromString(String str) {
         return ContinuationDecoder.decode(str);
     }
+
+    /** Returns a deep copy of this */
+    public abstract Continuation copy();
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/GroupingRequest.java b/container-search/src/main/java/com/yahoo/search/grouping/GroupingRequest.java
index b023166fe9e..754d3b562d3 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/GroupingRequest.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/GroupingRequest.java
@@ -8,6 +8,7 @@ import com.yahoo.search.Result;
 import com.yahoo.search.grouping.request.GroupingOperation;
 import com.yahoo.search.grouping.result.Group;
 import com.yahoo.search.grouping.result.RootGroup;
+import com.yahoo.search.query.Select;
 import com.yahoo.search.result.Hit;
 
 import java.util.*;
@@ -19,34 +20,53 @@ import java.util.*;
  * result {@link Group} using the {@link #getResultGroup(Result)} method.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class GroupingRequest {
 
+    private final Select parent;
     private final List<Continuation> continuations = new ArrayList<>();
-    private final int requestId;
     private GroupingOperation root;
     private TimeZone timeZone;
     private URI resultId;
 
-    private GroupingRequest(int requestId) {
-        this.requestId = requestId;
+    private GroupingRequest(Select parent) {
+        this.parent = parent;
+    }
+
+    private GroupingRequest(Select parent,
+                            List<Continuation> continuations,
+                            GroupingOperation root,
+                            TimeZone timeZone,
+                            URI resultId) {
+        this.parent = parent;
+        continuations.forEach(item -> this.continuations.add(item.copy()));
+        this.root = root != null ? root.copy(null) : null;
+        this.timeZone = timeZone;
+        this.resultId = resultId;
+    }
+
+    /** Returns a deep copy of this */
+    public GroupingRequest copy(Select parentOfCopy) {
+        return new GroupingRequest(parentOfCopy, continuations, root, timeZone, resultId);
     }
 
     /**
-     * Returns the id of this GroupingRequest. This id is injected into the {@link RootGroup} of the final result, and
+     * Returns the id of this GroupingRequest.
+     * This id is injected into the {@link RootGroup} of the final result, and
      * allows tracking of per-request meta data.
      *
-     * @return The id of this.
+     * @return the id of this request, or -1 if it has been removed from the query select statement
      */
     public int getRequestId() {
-        return requestId;
+        return parent.getGrouping().indexOf(this);
     }
 
     /**
      * Returns the root {@link GroupingOperation} that defines this request. As long as this remains unset, the request
      * is void.
      *
-     * @return The root operation.
+     * @return the root operation.
      */
     public GroupingOperation getRootOperation() {
         return root;
@@ -56,8 +76,8 @@ public class GroupingRequest {
      * Sets the root {@link GroupingOperation} that defines this request. As long as this remains unset, the request is
      * void.
      *
-     * @param root The root operation to set.
-     * @return This, to allow chaining.
+     * @param root the root operation to set.
+     * @return this, to allow chaining.
      */
     public GroupingRequest setRootOperation(GroupingOperation root) {
         this.root = root;
@@ -68,7 +88,7 @@ public class GroupingRequest {
      * Returns the {@link TimeZone} used when resolving time expressions such as {@link
      * com.yahoo.search.grouping.request.DayOfMonthFunction} and {@link com.yahoo.search.grouping.request.HourOfDayFunction}.
      *
-     * @return The time zone in use.
+     * @return the time zone in use.
      */
     public TimeZone getTimeZone() {
         return timeZone;
@@ -78,8 +98,8 @@ public class GroupingRequest {
      * Sets the {@link TimeZone} used when resolving time expressions such as {@link
      * com.yahoo.search.grouping.request.DayOfMonthFunction} and {@link com.yahoo.search.grouping.request.HourOfDayFunction}.
      *
-     * @param timeZone The time zone to set.
-     * @return This, to allow chaining.
+     * @param timeZone the time zone to set.
+     * @return this, to allow chaining.
      */
     public GroupingRequest setTimeZone(TimeZone timeZone) {
         this.timeZone = timeZone;
@@ -91,8 +111,8 @@ public class GroupingRequest {
      * search returns. Because searchers are allowed to modify both {@link Result} and {@link Hit} objects freely, this
      * method requires that you pass it the current {@link Result} object as argument.
      *
-     * @param result The search result that contains the root group.
-     * @return The result {@link RootGroup} of this request, or null if not found.
+     * @param result the search result that contains the root group.
+     * @return the result {@link RootGroup} of this request, or null if not found.
      */
     public RootGroup getResultGroup(Result result) {
         Hit root = result.hits().get(resultId, -1);
@@ -106,8 +126,8 @@ public class GroupingRequest {
      * Sets the result {@link RootGroup} of this request. This is used by the executing grouping searcher, and should
      * not be called by a requesting searcher.
      *
-     * @param group The result to set.
-     * @return This, to allow chaining.
+     * @param group the result to set.
+     * @return this, to allow chaining.
      */
     public GroupingRequest setResultGroup(RootGroup group) {
         this.resultId = group.getId();
@@ -118,36 +138,41 @@ public class GroupingRequest {
      * Returns the list of {@link Continuation}s of this request. This is used by the executing grouping searcher to
      * allow pagination of grouping results.
      *
-     * @return The list of Continuations.
+     * @return the list of Continuations.
      */
     public List<Continuation> continuations() {
         return continuations;
     }
 
     /**
-     * Creates and attaches a new instance of this class to the given {@link Query}. This is necessary to allow {@link
-     * #getRequests(Query)} to return all created requests.
+     * Creates a new grouping request and adds it to the query.getSelect().getGrouping() list
      *
-     * @param query The query to attach the request to.
+     * @param query the query to attach the request to.
      * @return The created request.
      */
     public static GroupingRequest newInstance(Query query) {
-        List<GroupingRequest> lst = getRequests(query);
-        GroupingRequest ret = new GroupingRequest(lst.size());
-        lst.add(ret);
-        return ret;
+        GroupingRequest newRequest = new GroupingRequest(query.getSelect());
+        query.getSelect().getGrouping().add(newRequest);
+        return newRequest;
     }
 
     /**
      * Returns all instances of this class that have been attached to the given {@link Query}. If no requests have been
      * attached to the {@link Query}, this method returns an empty list.
      *
-     * @param query The query whose requests to return.
-     * @return The list of grouping requests.
+     * @param query the query whose requests to return.
+     * @return the list of grouping requests.
+     * @deprecated use query.getSelect().getGrouping()
      */
     @SuppressWarnings({ "unchecked" })
     @Deprecated
     public static List<GroupingRequest> getRequests(Query query) {
         return query.getSelect().getGrouping();
     }
+
+    @Override
+    public String toString() {
+        return root == null ? "(empty)" : root.toString();
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/GroupingValidator.java b/container-search/src/main/java/com/yahoo/search/grouping/GroupingValidator.java
index 6379c43bc87..d96f490909e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/GroupingValidator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/GroupingValidator.java
@@ -63,9 +63,8 @@ public class GroupingValidator extends Searcher {
     public Result search(Query query, Execution execution) {
         if (enabled && query.properties().getBoolean(PARAM_ENABLED, true)) {
             ExpressionVisitor visitor = new MyVisitor();
-            for (GroupingRequest req : GroupingRequest.getRequests(query)) {
+            for (GroupingRequest req : query.getSelect().getGrouping())
                 req.getRootOperation().visitExpressions(visitor);
-            }
         }
         return execution.search(query);
     }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AddFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AddFunction.java
index 8cb27569e67..420861d2f6c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AddFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AddFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents an add-function in a {@link GroupingExpression}. It evaluates to a number that equals the
  * result of adding the results of all arguments together in the order they were given to the constructor.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AddFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class AddFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public AddFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private AddFunction(List<GroupingExpression> args) {
-        super("add", args);
+    private AddFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("add", label, level, args);
+    }
+
+    @Override
+    public AddFunction copy() {
+        return new AddFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,6 +46,6 @@ public class AddFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new AddFunction(args);
+        return new AddFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AggregatorNode.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AggregatorNode.java
index 323f1ac769a..6166833999a 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AggregatorNode.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AggregatorNode.java
@@ -12,13 +12,13 @@ public abstract class AggregatorNode extends GroupingExpression {
 
     private final GroupingExpression exp;
 
-    protected AggregatorNode(String image) {
-        super(image + "()");
+    protected AggregatorNode(String image, String label, Integer level) {
+        super(image + "()", label, level);
         this.exp = null;
     }
 
-    protected AggregatorNode(String image, GroupingExpression exp) {
-        super(image + "(" + exp.toString() + ")");
+    protected AggregatorNode(String image, String label, Integer level, GroupingExpression exp) {
+        super(image + "(" + exp.toString() + ")", label, level);
         this.exp = exp;
     }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AllOperation.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AllOperation.java
index b809706331f..93b46d95d89 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AllOperation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AllOperation.java
@@ -1,11 +1,16 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.search.grouping.request;
 
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * This is a grouping operation that processes the input list as a whole, as opposed to {@link EachOperation} which
  * processes each element of that list separately.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AllOperation extends GroupingOperation {
 
@@ -13,6 +18,44 @@ public class AllOperation extends GroupingOperation {
      * Constructs a new instance of this class.
      */
     public AllOperation() {
-        super("all");
+        super("all", null);
+    }
+
+    private AllOperation(GroupingOperation parentOfCopy,
+                         String image,
+                         String label,
+                         List<GroupingExpression> orderBy,
+                         List<GroupingExpression> outputs,
+                         List<GroupingOperation> children,
+                         Map<String, GroupingExpression> aliases,
+                         Set<String> hints,
+                         GroupingExpression groupBy,
+                         String where,
+                         boolean forceSinglePass,
+                         double accuracy,
+                         int precision,
+                         int level,
+                         int max) {
+        super(parentOfCopy, image, label, orderBy, outputs, children, aliases, hints, groupBy, where, forceSinglePass, accuracy, precision, level, max);
     }
+
+    @Override
+    public AllOperation copy(GroupingOperation parentOfCopy) {
+        return new AllOperation(parentOfCopy,
+                                getImage(),
+                                getLabel(),
+                                getOrderBy(),
+                                getOutputs(),
+                                getChildren(),
+                                getAliases(),
+                                getHints(),
+                                getGroupBy(),
+                                getWhere(),
+                                getForceSinglePass(),
+                                getAccuracy(),
+                                getPrecision(),
+                                getLevel(),
+                                getMax());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AndFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AndFunction.java
index 5f2617acf16..569f0d06987 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AndFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AndFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents an and-function in a {@link GroupingExpression}. It evaluates to a long that equals the result
  * of and'ing the results of all arguments together in the order they were given to the constructor.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AndFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class AndFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a long.
      */
     public AndFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private AndFunction(List<GroupingExpression> args) {
-        super("and", args);
+    private AndFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("and", label, level, args);
+    }
+
+    @Override
+    public AndFunction copy() {
+        return new AndFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,6 +46,6 @@ public class AndFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new AndFunction(args);
+        return new AndFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ArrayAtLookup.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ArrayAtLookup.java
index ed69e8aaee7..c8e0a6be3e8 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ArrayAtLookup.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ArrayAtLookup.java
@@ -19,34 +19,36 @@ import com.google.common.annotations.Beta;
 public class ArrayAtLookup extends DocumentValue {
 
     private final String attributeName;
-    private final GroupingExpression arg2;
+    private final GroupingExpression indexArgument;
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param attributeName The attribute name to assign to this.
+     * @param attributeName the attribute name to assign to this.
      */
     public ArrayAtLookup(String attributeName, GroupingExpression indexArg) {
-        super("array.at(" + attributeName + ", " + indexArg + ")");
+        this(null, null, attributeName, indexArg);
+    }
+
+    private ArrayAtLookup(String label, Integer level, String attributeName, GroupingExpression indexArgument) {
+        super("array.at(" + attributeName + ", " + indexArgument + ")", label, level);
         this.attributeName = attributeName;
-        this.arg2 = indexArg;
+        this.indexArgument = indexArgument;
     }
 
-    /**
-     * Returns the name of the attribute to retrieve from the input hit.
-     *
-     * @return The attribute name.
-     */
+    @Override
+    public ArrayAtLookup copy() {
+        return new ArrayAtLookup(getLabel(), getLevelOrNull(), getAttributeName(), getIndexArgument().copy());
+    }
+
+    /** Returns the name of the attribute to retrieve from the input hit */
     public String getAttributeName() {
         return attributeName;
     }
 
-    /**
-     * get the expression to evaluate before indexing
-     * @return grouping expression argument
-     */
+    /** Return the expression to evaluate before indexing */
     public GroupingExpression getIndexArgument() {
-	return arg2;
+        return indexArgument;
     }
 
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeFunction.java
index faf565647c7..d609800cc1c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeFunction.java
@@ -6,6 +6,7 @@ package com.yahoo.search.grouping.request;
  * named attribute in the input {@link com.yahoo.search.result.Hit}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AttributeFunction extends DocumentValue {
 
@@ -17,8 +18,17 @@ public class AttributeFunction extends DocumentValue {
      * @param attributeName the attribute name to assign to this.
      */
     public AttributeFunction(String attributeName) {
-        super("attribute(" + attributeName + ")");
-        name = attributeName;
+        this(null, null, attributeName);
+    }
+
+    private AttributeFunction(String label, Integer level, String attributeName) {
+        super("attribute(" + attributeName + ")", label, level);
+        this.name = attributeName;
+    }
+
+    @Override
+    public AttributeFunction copy() {
+        return new AttributeFunction(getLabel(), getLevelOrNull(), getAttributeName());
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeValue.java
index d83888b3107..1afac32d488 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AttributeValue.java
@@ -6,6 +6,7 @@ package com.yahoo.search.grouping.request;
  * named attribute in the input {@link com.yahoo.search.result.Hit}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AttributeValue extends DocumentValue {
 
@@ -17,8 +18,17 @@ public class AttributeValue extends DocumentValue {
      * @param attributeName the attribute name to assign to this.
      */
     public AttributeValue(String attributeName) {
-        super(attributeName);
-        name = attributeName;
+        this(null, null, attributeName);
+    }
+
+    private AttributeValue(String label, Integer level, String attributeName) {
+        super(attributeName, label, level);
+        this.name = attributeName;
+    }
+
+    @Override
+    public AttributeValue copy() {
+        return new AttributeValue(getLabel(), getLevelOrNull(), getAttributeName());
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AvgAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AvgAggregator.java
index d7e3232ea5f..bf11da5d2b9 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AvgAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AvgAggregator.java
@@ -6,15 +6,26 @@ package com.yahoo.search.grouping.request;
  * the contained expression evaluated to over all the inputs.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AvgAggregator extends AggregatorNode {
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param exp The expression to aggregate on.
+     * @param expression the expression to aggregate on.
      */
-    public AvgAggregator(GroupingExpression exp) {
-        super("avg", exp);
+    public AvgAggregator(GroupingExpression expression) {
+        this(null, null, expression);
     }
+
+    private AvgAggregator(String label, Integer level, GroupingExpression expression) {
+        super("avg", label, level, expression);
+    }
+
+    @Override
+    public AvgAggregator copy() {
+        return new AvgAggregator(getLabel(), getLevelOrNull(), getExpression().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/AvgFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/AvgFunction.java
index 55c4d355589..775f6c48d66 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/AvgFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/AvgFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a min-function in a {@link GroupingExpression}. It evaluates to a number that equals the
  * average of the results of all arguments.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class AvgFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class AvgFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public AvgFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private AvgFunction(List<GroupingExpression> args) {
-        super("avg", args);
+    private AvgFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("avg", label, level, args);
+    }
+
+    @Override
+    public AvgFunction copy() {
+        return new AvgFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,6 +46,6 @@ public class AvgFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new AvgFunction(args);
+        return new AvgFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/BooleanValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/BooleanValue.java
index 8b8903c9a8d..32ef3c16d2e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/BooleanValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/BooleanValue.java
@@ -4,7 +4,8 @@ package com.yahoo.search.grouping.request;
 /**
  * This class represents a constant {@link Boolean} value in a {@link GroupingExpression}.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
+ * @author bratseth
  */
 public class BooleanValue extends ConstantValue<Boolean> {
 
@@ -14,6 +15,16 @@ public class BooleanValue extends ConstantValue<Boolean> {
      * @param value The immutable value to assign to this.
      */
     public BooleanValue(Boolean value) {
-        super(value);
+        super(null, null, value);
     }
+
+    private BooleanValue(String label, Integer level, Boolean value) {
+        super(label, level, value);
+    }
+
+    @Override
+    public BooleanValue copy() {
+        return new BooleanValue(getLabel(), getLevelOrNull(), getValue());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/BucketValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/BucketValue.java
index c73b7199394..392c6386eb7 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/BucketValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/BucketValue.java
@@ -14,8 +14,8 @@ public class BucketValue extends GroupingExpression implements Comparable<Bucket
     private final ConstantValue<?> to;
     private final ConstantValueComparator comparator = new ConstantValueComparator();
 
-    protected BucketValue(ConstantValue<?> inclusiveFrom, ConstantValue<?> exclusiveTo) {
-        super("bucket[" + asImage(inclusiveFrom) + ", " + asImage(exclusiveTo) + ">");
+    protected BucketValue(String label, Integer level, ConstantValue<?> inclusiveFrom, ConstantValue<?> exclusiveTo) {
+        super("bucket[" + asImage(inclusiveFrom) + ", " + asImage(exclusiveTo) + ">", label, level);
         if (comparator.compare(exclusiveTo, inclusiveFrom) < 0) {
             throw new IllegalArgumentException("Bucket to-value can not be less than from-value.");
         }
@@ -23,6 +23,11 @@ public class BucketValue extends GroupingExpression implements Comparable<Bucket
         to = exclusiveTo;
     }
 
+    @Override
+    public BucketValue copy() {
+        return new BucketValue(getLabel(), getLevelOrNull(), getFrom().copy(), getTo().copy());
+    }
+
     /**
      * Returns the inclusive-from value of this bucket.
      *
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/CatFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/CatFunction.java
index 5e51c8e35a0..dddc3df0542 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/CatFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/CatFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a cat-function in a {@link GroupingExpression}. It evaluates to a byte array that equals the
  * concatenation of the binary result of all arguments in the order they were given to the constructor.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class CatFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class CatFunction extends FunctionNode {
      * @param argN The optional arguments.
      */
     public CatFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private CatFunction(List<GroupingExpression> args) {
-        super("cat", args);
+    private CatFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("cat", label, level, args);
+    }
+
+    @Override
+    public CatFunction copy() {
+        return new CatFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,6 +46,6 @@ public class CatFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new CatFunction(args);
+        return new CatFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValue.java
index ad8c1ef1cc9..81712424829 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValue.java
@@ -7,23 +7,24 @@ package com.yahoo.search.grouping.request;
  * data types are represented as subclasses of this.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 @SuppressWarnings("rawtypes")
 public abstract class ConstantValue<T extends Comparable> extends GroupingExpression {
 
     private final T value;
 
-    protected ConstantValue(T value) {
-        super(asImage(value));
+    protected ConstantValue(String label, Integer level, T value) {
+        super(asImage(value), label, level);
         this.value = value;
     }
 
-    /**
-     * Returns the constant value of this.
-     *
-     * @return The value.
-     */
+    @Override
+    public abstract ConstantValue copy();
+
+    /** Returns the constant value of this */
     public T getValue() {
         return value;
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValueComparator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValueComparator.java
index 543a1f495c6..61118e04784 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValueComparator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ConstantValueComparator.java
@@ -7,10 +7,11 @@ import java.util.Comparator;
  * This class compares two constant values, and takes into account that one of
  * the arguments may be the very special infinity value.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
  */
 @SuppressWarnings("rawtypes")
 public class ConstantValueComparator implements Comparator<ConstantValue> {
+
     @SuppressWarnings("unchecked")
     @Override
     public int compare(ConstantValue lhs, ConstantValue rhs) {
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/CountAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/CountAggregator.java
index 19a6c939087..b9d691500ad 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/CountAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/CountAggregator.java
@@ -6,13 +6,22 @@ package com.yahoo.search.grouping.request;
  * there are in the input.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class CountAggregator extends AggregatorNode {
 
-    /**
-     * Constructs a new instance of this class.
-     */
+    /** Constructs a new instance of this class. */
     public CountAggregator() {
-        super("count");
+        this(null, null);
     }
+
+    private CountAggregator(String label, Integer level) {
+        super("count", label, level);
+    }
+
+    @Override
+    public CountAggregator copy() {
+        return new CountAggregator(getLabel(), getLevelOrNull());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DateFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DateFunction.java
index b3a4c451b6b..0c2c4928a91 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DateFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DateFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.Arrays;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a timestamp-formatter function in a {@link GroupingExpression}. It evaluates to a string on the
  * form "YYYY-MM-DD" of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DateFunction extends FunctionNode {
 
@@ -17,6 +19,18 @@ public class DateFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public DateFunction(GroupingExpression exp) {
-        super("time.date", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private DateFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.date", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public DateFunction copy() {
+        return new DateFunction(getLabel(),
+                                getLevelOrNull(),
+                                getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfMonthFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfMonthFunction.java
index 5d82a80352b..62c23804344 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfMonthFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfMonthFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.Arrays;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a day-of-month timestamp-function in a {@link GroupingExpression}. It evaluates to a long that
  * equals the day of month (1-31) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DayOfMonthFunction extends FunctionNode {
 
@@ -17,6 +19,18 @@ public class DayOfMonthFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public DayOfMonthFunction(GroupingExpression exp) {
-        super("time.dayofmonth", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private DayOfMonthFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.dayofmonth", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public DayOfMonthFunction copy() {
+        return new DayOfMonthFunction(getLabel(),
+                                      getLevelOrNull(),
+                                      getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfWeekFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfWeekFunction.java
index f2135427bf5..6730db2e8d6 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfWeekFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfWeekFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * equals the day of week (0 - 6) of the result of the argument, Monday being 0.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DayOfWeekFunction extends FunctionNode {
 
@@ -17,6 +18,18 @@ public class DayOfWeekFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public DayOfWeekFunction(GroupingExpression exp) {
-        super("time.dayofweek", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private DayOfWeekFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.dayofweek", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public DayOfWeekFunction copy() {
+        return new DayOfWeekFunction(getLabel(),
+                                      getLevelOrNull(),
+                                      getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfYearFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfYearFunction.java
index 15f158ef2f1..9ff59c26fe5 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfYearFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DayOfYearFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * equals the day of year (0-365) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DayOfYearFunction extends FunctionNode {
 
@@ -17,6 +18,18 @@ public class DayOfYearFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public DayOfYearFunction(GroupingExpression exp) {
-        super("time.dayofyear", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private DayOfYearFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.dayofyear", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public DayOfYearFunction copy() {
+        return new DayOfYearFunction(getLabel(),
+                                     getLevelOrNull(),
+                                     getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DebugWaitFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DebugWaitFunction.java
index be0bb66f91f..5cad8ea55ec 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DebugWaitFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DebugWaitFunction.java
@@ -2,13 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.Arrays;
+import java.util.stream.Collectors;
 
 /**
  * This class represents debug_wait function in a {@link GroupingExpression}. For each hit evaluated,
  * it waits for the time specified as the second argument. The third argument specifies if the wait
  * should be a busy-wait or not. The first argument is then evaluated.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
  */
 public class DebugWaitFunction extends FunctionNode {
 
@@ -20,7 +21,20 @@ public class DebugWaitFunction extends FunctionNode {
      * @param arg3 The third compulsory argument, specifying busy wait or not.
      */
     public DebugWaitFunction(GroupingExpression arg1, DoubleValue arg2, BooleanValue arg3) {
-        super("debugwait", Arrays.asList(arg1, arg2, arg3));
+        this(null, null, arg1, arg2, arg3);
+    }
+
+    private DebugWaitFunction(String label, Integer level, GroupingExpression arg1, DoubleValue arg2, BooleanValue arg3) {
+        super("debugwait", label, level, Arrays.asList(arg1, arg2, arg3));
+    }
+
+    @Override
+    public DebugWaitFunction copy() {
+        return new DebugWaitFunction(getLabel(),
+                                     getLevelOrNull(),
+                                     getArg(0).copy(),
+                                     (DoubleValue)getArg(1).copy(),
+                                     (BooleanValue)getArg(2).copy());
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DivFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DivFunction.java
index f50dcde2d56..f559d911ff4 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DivFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DivFunction.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a div-function in a {@link GroupingExpression}. It evaluates to a number that equals the result
@@ -9,6 +10,7 @@ import java.util.List;
  * second, result by third, ...).
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DivFunction extends FunctionNode {
 
@@ -20,11 +22,18 @@ public class DivFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public DivFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private DivFunction(List<GroupingExpression> args) {
-        super("div", args);
+    private DivFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("div", label, level, args);
+    }
+
+    @Override
+    public DivFunction copy() {
+        return new DivFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -38,6 +47,6 @@ public class DivFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new DivFunction(args);
+        return new DivFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DocIdNsSpecificValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DocIdNsSpecificValue.java
index 188e642e7d7..d9a9daa2db5 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DocIdNsSpecificValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DocIdNsSpecificValue.java
@@ -6,6 +6,7 @@ package com.yahoo.search.grouping.request;
  * specific value of the document id of the input {@link com.yahoo.search.result.Hit}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DocIdNsSpecificValue extends DocumentValue {
 
@@ -13,7 +14,16 @@ public class DocIdNsSpecificValue extends DocumentValue {
      * Constructs a new instance of this class.
      */
     public DocIdNsSpecificValue() {
-        super("docidnsspecific()");
+        this(null, null);
+    }
+
+    private DocIdNsSpecificValue(String label, Integer level) {
+        super("docidnsspecific()", label, level);
+    }
+
+    @Override
+    public DocIdNsSpecificValue copy() {
+        return new DocIdNsSpecificValue(getLabel(), getLevelOrNull());
     }
 
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DocumentValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DocumentValue.java
index f8756b81163..f8b18e4acd6 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DocumentValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DocumentValue.java
@@ -9,8 +9,8 @@ package com.yahoo.search.grouping.request;
  */
 public abstract class DocumentValue extends GroupingExpression {
 
-    protected DocumentValue(String image) {
-        super(image);
+    protected DocumentValue(String image, String label, Integer level) {
+        super(image, label, level);
     }
 
     @Override
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleBucket.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleBucket.java
index d71ec8093fd..f0bcfead39a 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleBucket.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleBucket.java
@@ -26,7 +26,7 @@ public class DoubleBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public DoubleBucket(double from, double to) {
-        super(new DoubleValue(from), new DoubleValue(to));
+        super(null, null, new DoubleValue(from), new DoubleValue(to));
     }
 
     /**
@@ -36,6 +36,16 @@ public class DoubleBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public DoubleBucket(ConstantValue<?> from, ConstantValue<?> to) {
-        super(from, to);
+        super(null, null, from, to);
     }
+
+    private DoubleBucket(String label, Integer level, ConstantValue<?> from, ConstantValue<?> to) {
+        super(label, level, from, to);
+    }
+
+    @Override
+    public DoubleBucket copy() {
+        return new DoubleBucket(getLabel(), getLevelOrNull(), getFrom().copy(), getTo().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DoublePredefined.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DoublePredefined.java
index d43e8412623..0409709f2a2 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DoublePredefined.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DoublePredefined.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a predefined bucket-function in a {@link GroupingExpression} for expressions that evaluate to a
@@ -19,11 +20,22 @@ public class DoublePredefined extends PredefinedFunction {
      * @param argN The optional buckets.
      */
     public DoublePredefined(GroupingExpression exp, DoubleBucket arg1, DoubleBucket... argN) {
-        this(exp, asList(arg1, argN));
+        this(null, null, exp, asList(arg1, argN));
     }
 
-    private DoublePredefined(GroupingExpression exp, List<DoubleBucket> args) {
-        super(exp, args);
+    private DoublePredefined(String label, Integer level, GroupingExpression exp, List<DoubleBucket> args) {
+        super(label, level, exp, args);
+    }
+
+    @Override
+    public DoublePredefined copy() {
+        return new DoublePredefined(getLabel(),
+                                    getLevelOrNull(),
+                                    getArg(0),
+                                    args().stream().skip(1)
+                                                   .map(DoubleBucket.class::cast)
+                                                   .map(arg -> arg.copy())
+                                                   .collect(Collectors.toList()));
     }
 
     @Override
@@ -43,6 +55,6 @@ public class DoublePredefined extends PredefinedFunction {
         if (args.isEmpty()) {
             throw new IllegalArgumentException("Expected at least one bucket, got none.");
         }
-        return new DoublePredefined(exp, args);
+        return new DoublePredefined(null, null, exp, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleValue.java
index 5dad65aaabf..318cc680f2e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/DoubleValue.java
@@ -5,6 +5,7 @@ package com.yahoo.search.grouping.request;
  * This class represents a constant {@link Double} value in a {@link GroupingExpression}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class DoubleValue extends ConstantValue<Double> {
 
@@ -14,6 +15,16 @@ public class DoubleValue extends ConstantValue<Double> {
      * @param value The immutable value to assign to this.
      */
     public DoubleValue(double value) {
-        super(value);
+        super(null, null, value);
     }
+
+   private DoubleValue(String label, Integer level, Double value) {
+        super(label, level, value);
+    }
+
+    @Override
+    public DoubleValue copy() {
+        return new DoubleValue(getLabel(), getLevelOrNull(), getValue());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/EachOperation.java b/container-search/src/main/java/com/yahoo/search/grouping/request/EachOperation.java
index 1a7074a2c6e..2d830fd214e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/EachOperation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/EachOperation.java
@@ -1,11 +1,16 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.search.grouping.request;
 
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
 /**
  * This is a grouping operation that processes each element of the input list separately, as opposed to {@link
  * AllOperation} which processes that list as a whole.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class EachOperation extends GroupingOperation {
 
@@ -13,7 +18,44 @@ public class EachOperation extends GroupingOperation {
      * Constructs a new instance of this class.
      */
     public EachOperation() {
-        super("each");
+        super("each", null);
+    }
+
+    private EachOperation(GroupingOperation parentOfCopy,
+                          String image,
+                          String label,
+                          List<GroupingExpression> orderBy,
+                          List<GroupingExpression> outputs,
+                          List<GroupingOperation> children,
+                          Map<String, GroupingExpression> aliases,
+                          Set<String> hints,
+                          GroupingExpression groupBy,
+                          String where,
+                          boolean forceSinglePass,
+                          double accuracy,
+                          int precision,
+                          int level,
+                          int max) {
+        super(parentOfCopy, image, label, orderBy, outputs, children, aliases, hints, groupBy, where, forceSinglePass, accuracy, precision, level, max);
+    }
+
+    @Override
+    public EachOperation copy(GroupingOperation parentOfCopy) {
+        return new EachOperation(parentOfCopy,
+                                 getImage(),
+                                 getLabel(),
+                                 getOrderBy(),
+                                 getOutputs(),
+                                 getChildren(),
+                                 getAliases(),
+                                 getHints(),
+                                 getGroupBy(),
+                                 getWhere(),
+                                 getForceSinglePass(),
+                                 getAccuracy(),
+                                 getPrecision(),
+                                 getLevel(),
+                                 getMax());
     }
 
     @Override
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ExpressionVisitor.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ExpressionVisitor.java
index a341bee2568..89d698694a8 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ExpressionVisitor.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ExpressionVisitor.java
@@ -13,7 +13,8 @@ public interface ExpressionVisitor {
     /**
      * This method is called for every {@link GroupingExpression} object in the targeted {@link GroupingOperation}.
      *
-     * @param exp The expression being visited.
+     * @param exp the expression being visited.
      */
-    public void visitExpression(GroupingExpression exp);
+    void visitExpression(GroupingExpression exp);
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/FixedWidthFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/FixedWidthFunction.java
index f44394c6193..3b397634a11 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/FixedWidthFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/FixedWidthFunction.java
@@ -18,7 +18,17 @@ public class FixedWidthFunction extends FunctionNode {
      * @param width The width of each bucket.
      */
     public FixedWidthFunction(GroupingExpression exp, Number width) {
-        super("fixedwidth", Arrays.asList(exp, width instanceof Double ? new DoubleValue(width.doubleValue()) : new LongValue(width.longValue())));
+        this(null, null, exp,
+             width instanceof Double ? new DoubleValue(width.doubleValue()) : new LongValue(width.longValue()));
+    }
+
+    private FixedWidthFunction(String label, Integer level, GroupingExpression exp, ConstantValue width) {
+        super("fixedwidth", label, level, Arrays.asList(exp, width));
+    }
+
+    @Override
+    public FixedWidthFunction copy() {
+        return new FixedWidthFunction(getLabel(), getLevelOrNull(), getArg(0).copy(), (ConstantValue)getArg(1).copy());
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/FunctionNode.java b/container-search/src/main/java/com/yahoo/search/grouping/request/FunctionNode.java
index 1a059d79b1a..9e09baf66ab 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/FunctionNode.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/FunctionNode.java
@@ -14,8 +14,8 @@ public abstract class FunctionNode extends GroupingExpression implements Iterabl
 
     private final List<GroupingExpression> args = new ArrayList<>();
 
-    protected FunctionNode(String image, List<GroupingExpression> args) {
-        super(image + "(" + asString(args) + ")");
+    protected FunctionNode(String image, String label, Integer level, List<GroupingExpression> args) {
+        super(image + "(" + asString(args) + ")", label, level);
         this.args.addAll(args);
     }
 
@@ -39,6 +39,10 @@ public abstract class FunctionNode extends GroupingExpression implements Iterabl
         return args.get(i);
     }
 
+    /** Returns the arguments of this as a list which cannot be modified */
+    // Note: If this is made public the returned list must be immutable
+    protected List<GroupingExpression> args() { return args; }
+
     @Override
     public Iterator<GroupingExpression> iterator() {
         return Collections.unmodifiableList(args).iterator();
@@ -75,4 +79,5 @@ public abstract class FunctionNode extends GroupingExpression implements Iterabl
         ret.addAll(bar);
         return ret;
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java
index 2f7691156e5..ad97f5519ee 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingExpression.java
@@ -15,10 +15,14 @@ public abstract class GroupingExpression extends GroupingNode {
 
     private Integer level = null;
 
-    protected GroupingExpression(String image) {
-        super(image);
+    protected GroupingExpression(String image, String label, Integer level) {
+        super(image, label);
+        this.level = level;
     }
 
+    /** Returns a deep copy of this */
+    public abstract GroupingExpression copy();
+
     /**
      * Resolves the conceptual level of this expression. This level represents the type of data that is consumed by this
      * expression, where level 0 is a single hit, level 1 is a group, level 2 is a list of groups, and so forth. This
@@ -39,8 +43,8 @@ public abstract class GroupingExpression extends GroupingNode {
     /**
      * Returns the conceptual level of this expression.
      *
-     * @return The level.
-     * @throws IllegalArgumentException Thrown if the level of this expression has not been resolved.
+     * @return the level.
+     * @throws IllegalArgumentException thrown if the level of this expression has not been resolved.
      * @see #resolveLevel(int)
      */
     public int getLevel() {
@@ -50,6 +54,8 @@ public abstract class GroupingExpression extends GroupingNode {
         return level;
     }
 
+    protected final Integer getLevelOrNull() { return level; }
+
     /**
      * Recursively calls {@link ExpressionVisitor#visitExpression(GroupingExpression)} for this expression and all of
      * its argument expressions.
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingNode.java b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingNode.java
index 148b4243a4b..bd5db3d1fdb 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingNode.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingNode.java
@@ -10,10 +10,11 @@ package com.yahoo.search.grouping.request;
 public abstract class GroupingNode {
 
     private final String image;
-    private String label = null;
+    private String label;
 
-    protected GroupingNode(String image) {
+    protected GroupingNode(String image, String label) {
         this.image = image;
+        this.label = label;
     }
 
     /**
@@ -25,6 +26,8 @@ public abstract class GroupingNode {
         return label;
     }
 
+    protected String getImage() { return image; }
+
     /**
      * Assigns a label to this grouping expression. The label is applied to the results of this expression so that they
      * can be identified by the caller when processing the output.
@@ -41,4 +44,5 @@ public abstract class GroupingNode {
     public String toString() {
         return image;
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingOperation.java b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingOperation.java
index 4c29ca7d98d..93619913b4f 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingOperation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/GroupingOperation.java
@@ -23,7 +23,7 @@ public abstract class GroupingOperation extends GroupingNode {
     private final List<GroupingExpression> orderBy = new ArrayList<>();
     private final List<GroupingExpression> outputs = new ArrayList<>();
     private final List<GroupingOperation> children = new ArrayList<>();
-    private final Map<String, GroupingExpression> alias = LazyMap.newHashMap();
+    private final Map<String, GroupingExpression> aliases = LazyMap.newHashMap();
     private final Set<String> hints = LazySet.newHashSet();
 
     private GroupingExpression groupBy = null;
@@ -35,10 +35,44 @@ public abstract class GroupingOperation extends GroupingNode {
     private int level = -1;
     private int max = -1;
 
-    protected GroupingOperation(String image) {
-        super(image);
+    protected GroupingOperation(String image, String label) {
+        super(image, label);
+    }
+
+    protected GroupingOperation(GroupingOperation parentOfCopy,
+                                String image,
+                                String label,
+                                List<GroupingExpression> orderBy,
+                                List<GroupingExpression> outputs,
+                                List<GroupingOperation> children,
+                                Map<String, GroupingExpression> aliases,
+                                Set<String> hints,
+                                GroupingExpression groupBy,
+                                String where,
+                                boolean forceSinglePass,
+                                double accuracy,
+                                int precision,
+                                int level,
+                                int max) {
+        super(image, label);
+        this.parent = parentOfCopy;
+        orderBy.forEach(item -> this.orderBy.add(item.copy()));
+        outputs.forEach(item -> this.outputs.add(item.copy()));
+        children.forEach(item -> this.children.add(item.copy(this)));
+        aliases.forEach((key, value) -> this.aliases.put(key, value.copy()));
+        this.hints.addAll(hints);
+        if (groupBy != null) this.groupBy = groupBy.copy();
+        this.where = where;
+        this.forceSinglePass = forceSinglePass;
+        this.accuracy = accuracy;
+        this.precision = precision;
+        this.level = level;
+        this.max = max;
     }
 
+    /** Returns a deep copy of this */
+    public abstract GroupingOperation copy(GroupingOperation parentOfCopy);
+
     /**
      * Registers an alias with this operation. An alias is made available to expressions in both this node and all child
      * nodes.
@@ -48,7 +82,7 @@ public abstract class GroupingOperation extends GroupingNode {
      * @return This, to allow chaining.
      */
     public GroupingOperation putAlias(String id, GroupingExpression exp) {
-        alias.put(id, exp);
+        aliases.put(id, exp);
         return this;
     }
 
@@ -60,8 +94,8 @@ public abstract class GroupingOperation extends GroupingNode {
      * @return The expression associated with the id.
      */
     public GroupingExpression getAlias(String id) {
-        if (alias.containsKey(id)) {
-            return alias.get(id);
+        if (aliases.containsKey(id)) {
+            return aliases.get(id);
         } else if (parent != null) {
             return parent.getAlias(id);
         } else {
@@ -69,6 +103,11 @@ public abstract class GroupingOperation extends GroupingNode {
         }
     }
 
+    /** Returns a direct, mutable copy of the aliases of this, never null */
+    protected Map<String, GroupingExpression> getAliases() {
+        return aliases;
+    }
+
     /**
      * Adds a hint to this.
      *
@@ -225,6 +264,9 @@ public abstract class GroupingOperation extends GroupingNode {
         }
     }
 
+    /** Returns the parent of this, or null if none */
+    protected GroupingOperation getParent() { return parent; }
+
     public GroupingOperation setForceSinglePass(boolean forceSinglePass) {
         this.forceSinglePass = forceSinglePass;
         return this;
@@ -446,7 +488,7 @@ public abstract class GroupingOperation extends GroupingNode {
      * @param visitor The visitor to call.
      */
     public void visitExpressions(ExpressionVisitor visitor) {
-        for (GroupingExpression exp : alias.values()) {
+        for (GroupingExpression exp : aliases.values()) {
             exp.visit(visitor);
         }
         for (GroupingExpression exp : outputs) {
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/HourOfDayFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/HourOfDayFunction.java
index faf1c1e0289..7adebcbfbdb 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/HourOfDayFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/HourOfDayFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * equals the hour of day (0-23) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class HourOfDayFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class HourOfDayFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public HourOfDayFunction(GroupingExpression exp) {
-        super("time.hourofday", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private HourOfDayFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.hourofday", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public HourOfDayFunction copy() {
+        return new HourOfDayFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/Infinite.java b/container-search/src/main/java/com/yahoo/search/grouping/request/Infinite.java
index 53f5d3256ed..766571914cc 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/Infinite.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/Infinite.java
@@ -3,12 +3,13 @@ package com.yahoo.search.grouping.request;
 
 /**
  * This class represents an Infinite value that may be used as a bucket
- * size specifier.
+ * size specifier. This is immutable.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
  */
 @SuppressWarnings("rawtypes")
 public class Infinite implements Comparable {
+
     private final boolean negative;
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/InfiniteValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/InfiniteValue.java
index 7c2730992df..dac6259595d 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/InfiniteValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/InfiniteValue.java
@@ -4,7 +4,8 @@ package com.yahoo.search.grouping.request;
 /**
  * This class represents an infinite value in a {@link GroupingExpression}.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
+ * @author bratseth
  */
 public class InfiniteValue extends ConstantValue<Infinite> {
 
@@ -14,6 +15,16 @@ public class InfiniteValue extends ConstantValue<Infinite> {
      * @param value The immutable value to assign to this.
      */
     public InfiniteValue(Infinite value) {
-        super(value);
+        super(null, null, value);
     }
+
+    private InfiniteValue(String label, Integer level, Infinite value) {
+        super(label, level, value);
+    }
+
+    @Override
+    public InfiniteValue copy() {
+        return new InfiniteValue(getLabel(), getLevelOrNull(), getValue());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/InterpolatedLookup.java b/container-search/src/main/java/com/yahoo/search/grouping/request/InterpolatedLookup.java
index dc8b6d68dc3..279434f1df2 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/InterpolatedLookup.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/InterpolatedLookup.java
@@ -18,34 +18,37 @@ import com.google.common.annotations.Beta;
 public class InterpolatedLookup extends DocumentValue {
 
     private final String attributeName;
-    private final GroupingExpression arg2;
+    private final GroupingExpression lookupArgument;
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param attributeName The attribute name the lookup should happen in
-     * @param lookupArg Expression giving a floating-point value for the lookup argument
+     * @param attributeName the attribute name to assign to this.
+     * @param lookupArgument Expression giving a floating-point value for the lookup argument
      */
-    public InterpolatedLookup(String attributeName, GroupingExpression lookupArg) {
-        super("interpolatedlookup(" + attributeName + ", " + lookupArg + ")");
+    public InterpolatedLookup(String attributeName, GroupingExpression lookupArgument) {
+        this(null, null, attributeName, lookupArgument);
+    }
+
+    private InterpolatedLookup(String label, Integer level, String attributeName, GroupingExpression lookupArgument) {
+        super("interpolatedlookup(" + attributeName + ", " + lookupArgument + ")", label, level);
         this.attributeName = attributeName;
-	this.arg2 = lookupArg;
+        this.lookupArgument = lookupArgument;
     }
 
-    /**
-     * Get the name of the attribute to be retrieved from the input hit.
-     * @return The attribute name.
-     */
+    @Override
+    public InterpolatedLookup copy() {
+        return new InterpolatedLookup(getLabel(), getLevelOrNull(), getAttributeName(), getLookupArgument().copy());
+    }
+
+    /** Returns the name of the attribute to retrieve from the input hit */
     public String getAttributeName() {
         return attributeName;
     }
 
-    /**
-     * Get the expression that will be evaluated before lookup.
-     * @return grouping expression argument
-     */
+    /** Return the expression to evaluate before lookup */
     public GroupingExpression getLookupArgument() {
-	return arg2;
+        return lookupArgument;
     }
 
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/LongBucket.java b/container-search/src/main/java/com/yahoo/search/grouping/request/LongBucket.java
index fd363320033..a0fdf8f9526 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/LongBucket.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/LongBucket.java
@@ -12,7 +12,7 @@ public class LongBucket extends BucketValue {
      * Gives the next distinct long value.
      *
      * @param value the base value.
-     * @return the nextt value.
+     * @return the next value.
      */
     public static LongValue nextValue(LongValue value) {
         long v = value.getValue();
@@ -26,7 +26,7 @@ public class LongBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public LongBucket(long from, long to) {
-        super(new LongValue(from), new LongValue(to));
+        super(null, null, new LongValue(from), new LongValue(to));
     }
 
     /**
@@ -37,6 +37,16 @@ public class LongBucket extends BucketValue {
      */
     @SuppressWarnings("rawtypes")
     public LongBucket(ConstantValue from, ConstantValue to) {
-        super(from, to);
+        super(null, null, from, to);
     }
+
+    private LongBucket(String label, Integer level, ConstantValue<?> from, ConstantValue<?> to) {
+        super(label, level, from, to);
+    }
+
+    @Override
+    public LongBucket copy() {
+        return new LongBucket(getLabel(), getLevelOrNull(), getFrom().copy(), getTo().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/LongPredefined.java b/container-search/src/main/java/com/yahoo/search/grouping/request/LongPredefined.java
index 98acc800ed7..fe428d26db7 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/LongPredefined.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/LongPredefined.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a predefined bucket-function in a {@link GroupingExpression} for expressions that evaluate to a
  * long.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class LongPredefined extends PredefinedFunction {
 
@@ -19,11 +21,23 @@ public class LongPredefined extends PredefinedFunction {
      * @param argN The optional buckets.
      */
     public LongPredefined(GroupingExpression exp, LongBucket arg1, LongBucket... argN) {
-        this(exp, asList(arg1, argN));
+        this(null, null, exp, asList(arg1, argN));
     }
 
-    private LongPredefined(GroupingExpression exp, List<LongBucket> args) {
-        super(exp, args);
+    private LongPredefined(String label, Integer level, GroupingExpression exp, List<LongBucket> args) {
+        super(label, level, exp, args);
+    }
+
+    @Override
+    public LongPredefined copy() {
+        return new LongPredefined(getLabel(),
+                                  getLevelOrNull(),
+                                  getArg(0),
+                                  args().stream()
+                                        .skip(1)
+                                        .map(LongBucket.class::cast)
+                                        .map(arg -> arg.copy())
+                                        .collect(Collectors.toList()));
     }
 
     @Override
@@ -43,6 +57,6 @@ public class LongPredefined extends PredefinedFunction {
         if (args.isEmpty()) {
             throw new IllegalArgumentException("Expected at least one bucket, got none.");
         }
-        return new LongPredefined(exp, args);
+        return new LongPredefined(null, null, exp, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/LongValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/LongValue.java
index 4c4eb1c409d..705036af78e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/LongValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/LongValue.java
@@ -5,6 +5,7 @@ package com.yahoo.search.grouping.request;
  * This class represents a constant {@link Long} value in a {@link GroupingExpression}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class LongValue extends ConstantValue<Long> {
 
@@ -14,7 +15,16 @@ public class LongValue extends ConstantValue<Long> {
      * @param value the immutable value to assign to this.
      */
     public LongValue(long value) {
-        super(value);
+        super(null, null, value);
+    }
+
+    private LongValue(String label, Integer level, Long value) {
+        super(label, level, value);
+    }
+
+    @Override
+    public LongValue copy() {
+        return new LongValue(getLabel(), getLevelOrNull(), getValue());
     }
 
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosFunction.java
index 58d7275e8eb..24ba449e517 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathACosFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathACosFunction(GroupingExpression exp) {
-        super("math.acos", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathACosFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.acos", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathACosFunction copy() {
+        return new MathACosFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosHFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosHFunction.java
index eca8fd7ebf7..40de58ba0be 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosHFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathACosHFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathACosHFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathACosHFunction(GroupingExpression exp) {
-        super("math.acosh", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathACosHFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.acosh", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathACosHFunction copy() {
+        return new MathACosHFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinFunction.java
index 1189bccd5bc..48a2641b660 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathASinFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathASinFunction(GroupingExpression exp) {
-        super("math.asin", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathASinFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.asin", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathASinFunction copy() {
+        return new MathASinFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinHFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinHFunction.java
index 7619ab4f1b3..687bf1c6c34 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinHFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathASinHFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathASinHFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathASinHFunction(GroupingExpression exp) {
-        super("math.asinh", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathASinHFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.asinh", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathASinHFunction copy() {
+        return new MathASinHFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanFunction.java
index 114fd24644b..6612c9cc70f 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathATanFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathATanFunction(GroupingExpression exp) {
-        super("math.atan", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathATanFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.atan", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathATanFunction copy() {
+        return new MathATanFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanHFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanHFunction.java
index 08f7956e855..fa9844ec17b 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanHFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathATanHFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathATanHFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathATanHFunction(GroupingExpression exp) {
-        super("math.atanh", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathATanHFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.atanh", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathATanHFunction copy() {
+        return new MathATanHFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathCbrtFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathCbrtFunction.java
index 6978e89ba71..04595003a03 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathCbrtFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathCbrtFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathCbrtFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathCbrtFunction(GroupingExpression exp) {
-        super("math.cbrt", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathCbrtFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.cbrt", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathCbrtFunction copy() {
+        return new MathCbrtFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosFunction.java
index 846660c2370..95140ce06d0 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathCosFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathCosFunction(GroupingExpression exp) {
-        super("math.cos", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathCosFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.cos", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathCosFunction copy() {
+        return new MathCosFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosHFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosHFunction.java
index d370678d3f5..f0384666ffe 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosHFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathCosHFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathCosHFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathCosHFunction(GroupingExpression exp) {
-        super("math.cosh", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathCosHFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.cosh", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathCosHFunction copy() {
+        return new MathCosHFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathExpFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathExpFunction.java
index 812fd98faa9..ef2a53d90b0 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathExpFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathExpFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathExpFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathExpFunction(GroupingExpression exp) {
-        super("math.exp", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathExpFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.exp", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathExpFunction copy() {
+        return new MathExpFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathFloorFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathFloorFunction.java
index 31e5e99d974..64dd931f9e4 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathFloorFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathFloorFunction.java
@@ -3,14 +3,30 @@ package com.yahoo.search.grouping.request;
 
 import java.util.Arrays;
 
-/** represents the math.floor(expression) function */
+/**
+ * Represents the math.floor(expression) function
+ *
+ * @author baldersheim
+ * @author bratseth
+ */
 public class MathFloorFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathFloorFunction(GroupingExpression exp) {
-        super("math.floor", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathFloorFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.floor", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathFloorFunction copy() {
+        return new MathFloorFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathFunctions.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathFunctions.java
index 6e3e52c9563..5fc806a90fe 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathFunctions.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathFunctions.java
@@ -5,6 +5,7 @@ package com.yahoo.search.grouping.request;
  * @author baldersheim
  */
 public abstract class MathFunctions {
+
     /**
      * Defines the different types of math functions that are available.
      */
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathHypotFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathHypotFunction.java
index 596c7501af6..d6062124619 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathHypotFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathHypotFunction.java
@@ -5,8 +5,10 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathHypotFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
@@ -14,6 +16,16 @@ public class MathHypotFunction extends FunctionNode {
      * @param y The expression to evaluate for y exponent, double value will be requested.
      */
     public MathHypotFunction(GroupingExpression x, GroupingExpression y) {
-        super("math.hypot", Arrays.asList(x, y));
+        this(null, null, x, y);
+    }
+
+    private MathHypotFunction(String label, Integer level, GroupingExpression x, GroupingExpression y) {
+        super("math.hypot", label, level, Arrays.asList(x, y));
     }
+
+    @Override
+    public MathHypotFunction copy() {
+        return new MathHypotFunction(getLabel(), getLevelOrNull(), getArg(0).copy(), getArg(1).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog10Function.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog10Function.java
index 6a19de43f1c..b64e5d03a97 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog10Function.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog10Function.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathLog10Function extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathLog10Function(GroupingExpression exp) {
-        super("math.log10", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathLog10Function(String label, Integer level, GroupingExpression exp) {
+        super("math.log10", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathLog10Function copy() {
+        return new MathLog10Function(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog1pFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog1pFunction.java
index 06fc2424f41..7df97e6b0d5 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog1pFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathLog1pFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathLog1pFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathLog1pFunction(GroupingExpression exp) {
-        super("math.log1p", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathLog1pFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.log1p", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathLog1pFunction copy() {
+        return new MathLog1pFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathLogFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathLogFunction.java
index 0b71ad66bd9..323a03ad152 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathLogFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathLogFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathLogFunction extends FunctionNode {
-        /**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathLogFunction(GroupingExpression exp) {
-        super("math.log", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathLogFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.log", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathLogFunction copy() {
+        return new MathLogFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathPowFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathPowFunction.java
index ab0d6ba2139..084fdc82646 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathPowFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathPowFunction.java
@@ -5,8 +5,10 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathPowFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
@@ -14,6 +16,19 @@ public class MathPowFunction extends FunctionNode {
      * @param y The expression to evaluate for the exponent, double value will be requested.
      */
     public MathPowFunction(GroupingExpression x, GroupingExpression y) {
-        super("math.pow", Arrays.asList(x,y));
+        this(null, null, x, y);
+    }
+
+    private MathPowFunction(String label, Integer level, GroupingExpression x, GroupingExpression y) {
+        super("math.pow", label, level, Arrays.asList(x, y));
     }
+
+    @Override
+    public MathPowFunction copy() {
+        return new MathPowFunction(getLabel(),
+                                   getLevelOrNull(),
+                                   getArg(0).copy(),
+                                   getArg(1).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinFunction.java
index dd914807e7a..ea9a0d97887 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathSinFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathSinFunction(GroupingExpression exp) {
-        super("math.sin", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathSinFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.sin", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathSinFunction copy() {
+        return new MathSinFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinHFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinHFunction.java
index b600d947489..3a02de24e6a 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinHFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathSinHFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathSinHFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathSinHFunction(GroupingExpression exp) {
-        super("math.sinh", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathSinHFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.sinh", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathSinHFunction copy() {
+        return new MathSinHFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathSqrtFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathSqrtFunction.java
index e6a0c04e7ee..ee66b71e070 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathSqrtFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathSqrtFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathSqrtFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathSqrtFunction(GroupingExpression exp) {
-        super("math.sqrt", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathSqrtFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.sqrt", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathSqrtFunction copy() {
+        return new MathSqrtFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanFunction.java
index f66492f87ad..003ef9c6a00 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathTanFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathTanFunction(GroupingExpression exp) {
-        super("math.tan", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathTanFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.tan", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathTanFunction copy() {
+        return new MathTanFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanHFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanHFunction.java
index 93e7c1c1d49..86ccbbdfcf9 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanHFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MathTanHFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class MathTanHFunction extends FunctionNode {
-/**
+
+    /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, double value will be requested.
      */
     public MathTanHFunction(GroupingExpression exp) {
-        super("math.tanh", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private MathTanHFunction(String label, Integer level, GroupingExpression exp) {
+        super("math.tanh", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public MathTanHFunction copy() {
+        return new MathTanHFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MaxAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MaxAggregator.java
index 54dc7c6b3bd..513cba8fb19 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MaxAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MaxAggregator.java
@@ -6,15 +6,26 @@ package com.yahoo.search.grouping.request;
  * the contained expression evaluated to over all the inputs.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class MaxAggregator extends AggregatorNode {
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param exp The expression to aggregate on.
+     * @param expression the expression to aggregate on.
      */
-    public MaxAggregator(GroupingExpression exp) {
-        super("max", exp);
+    public MaxAggregator(GroupingExpression expression) {
+        this(null, null, expression);
     }
+
+    private MaxAggregator(String label, Integer level, GroupingExpression expression) {
+        super("max", label, level, expression);
+    }
+
+    @Override
+    public MaxAggregator copy() {
+        return new MaxAggregator(getLabel(), getLevelOrNull(), getExpression().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MaxFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MaxFunction.java
index 731c1c4eba4..bff8cb481b8 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MaxFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MaxFunction.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a max-function in a {@link GroupingExpression}. It evaluates to a number that equals the
@@ -19,11 +20,18 @@ public class MaxFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public MaxFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private MaxFunction(List<GroupingExpression> args) {
-        super("max", args);
+    private MaxFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("max", label, level, args);
+    }
+
+    @Override
+    public MaxFunction copy() {
+        return new MaxFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,7 +45,7 @@ public class MaxFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new MaxFunction(args);
+        return new MaxFunction(null, null, args);
     }
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/Md5Function.java b/container-search/src/main/java/com/yahoo/search/grouping/request/Md5Function.java
index 6ae33b804e9..1426d141ef7 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/Md5Function.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/Md5Function.java
@@ -18,7 +18,16 @@ public class Md5Function extends FunctionNode {
      * @param numBits The number of bits of the md5 to include.
      */
     public Md5Function(GroupingExpression exp, int numBits) {
-        super("md5", Arrays.asList(exp, new LongValue(numBits)));
+        this(null, null, exp, new LongValue(numBits));
+    }
+
+    private Md5Function(String label, Integer level, GroupingExpression exp, LongValue numBits) {
+        super("md5", label, level, Arrays.asList(exp, numBits));
+    }
+
+    @Override
+    public Md5Function copy() {
+        return new Md5Function(getLabel(), getLevelOrNull(), getArg(0).copy(), (LongValue)getArg(1).copy());
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MinAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MinAggregator.java
index 1a24527dcfc..07164ba4053 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MinAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MinAggregator.java
@@ -6,15 +6,26 @@ package com.yahoo.search.grouping.request;
  * the contained expression evaluated to over all the inputs.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class MinAggregator extends AggregatorNode {
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param exp The expression to aggregate on.
+     * @param expression the expression to aggregate on.
      */
-    public MinAggregator(GroupingExpression exp) {
-        super("min", exp);
+    public MinAggregator(GroupingExpression expression) {
+        this(null, null, expression);
     }
+
+    private MinAggregator(String label, Integer level, GroupingExpression expression) {
+        super("min", label, level, expression);
+    }
+
+    @Override
+    public MinAggregator copy() {
+        return new MinAggregator(getLabel(), getLevelOrNull(), getExpression().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MinFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MinFunction.java
index 478684dd73e..40fbda5a98a 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MinFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MinFunction.java
@@ -1,7 +1,9 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.search.grouping.request;
 
+import java.util.Arrays;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a min-function in a {@link GroupingExpression}. It evaluates to a number that equals the
@@ -19,11 +21,18 @@ public class MinFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public MinFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private MinFunction(List<GroupingExpression> args) {
-        super("min", args);
+    private MinFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("min", label, level, args);
+    }
+
+    @Override
+    public MinFunction copy() {
+        return new MinFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,7 +46,7 @@ public class MinFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new MinFunction(args);
+        return new MinFunction(null, null, args);
     }
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MinuteOfHourFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MinuteOfHourFunction.java
index d2442b8455e..97dfb5b0d37 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MinuteOfHourFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MinuteOfHourFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * that equals the minute of hour (0-59) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class MinuteOfHourFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class MinuteOfHourFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public MinuteOfHourFunction(GroupingExpression exp) {
-        super("time.minuteofhour", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private MinuteOfHourFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.minuteofhour", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public MinuteOfHourFunction copy() {
+        return new MinuteOfHourFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ModFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ModFunction.java
index a3fd1041e6e..33b5c7bf655 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ModFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ModFunction.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a mod-function in a {@link GroupingExpression}. It evaluates to a number that equals the result
@@ -20,11 +21,18 @@ public class ModFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public ModFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private ModFunction(List<GroupingExpression> args) {
-        super("mod", args);
+    private ModFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("mod", label, level, args);
+    }
+
+    @Override
+    public ModFunction copy() {
+        return new ModFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -38,6 +46,6 @@ public class ModFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new ModFunction(args);
+        return new ModFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MonthOfYearFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MonthOfYearFunction.java
index 96e08562e42..c6df8dbd408 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MonthOfYearFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MonthOfYearFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * equals the month of year (1-12) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class MonthOfYearFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class MonthOfYearFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public MonthOfYearFunction(GroupingExpression exp) {
-        super("time.monthofyear", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private MonthOfYearFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.monthofyear", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public MonthOfYearFunction copy() {
+        return new MonthOfYearFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/MulFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/MulFunction.java
index 84584270f58..7af8d22955e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/MulFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/MulFunction.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a mul-function in a {@link GroupingExpression}. It evaluates to a number that equals the result
@@ -19,11 +20,18 @@ public class MulFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public MulFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private MulFunction(List<GroupingExpression> args) {
-        super("mul", args);
+    private MulFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("mul", label, level, args);
+    }
+
+    @Override
+    public MulFunction copy() {
+        return new MulFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,6 +45,6 @@ public class MulFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new MulFunction(args);
+        return new MulFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java
index 7e05b02b59e..ad3b892970c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/NegFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * negative of the results of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class NegFunction extends FunctionNode {
 
@@ -17,7 +18,17 @@ public class NegFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a number.
      */
     public NegFunction(GroupingExpression exp) {
-        super("neg", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private NegFunction(String label, Integer level, GroupingExpression exp) {
+        super("neg", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public NegFunction copy() {
+        return new NegFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/NormalizeSubjectFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/NormalizeSubjectFunction.java
index 54a0062e2c9..8bf0a03141a 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/NormalizeSubjectFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/NormalizeSubjectFunction.java
@@ -13,7 +13,17 @@ public class NormalizeSubjectFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a string.
      */
     public NormalizeSubjectFunction(GroupingExpression exp) {
-        super("normalizesubject", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private NormalizeSubjectFunction(String label, Integer level, GroupingExpression exp) {
+        super("normalizesubject", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public NormalizeSubjectFunction copy() {
+        return new NormalizeSubjectFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/NowFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/NowFunction.java
index 24dd888e98d..75715bad37b 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/NowFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/NowFunction.java
@@ -1,6 +1,7 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.search.grouping.request;
 
+import java.util.Arrays;
 import java.util.Collections;
 
 /**
@@ -8,6 +9,7 @@ import java.util.Collections;
  * of seconds since midnight, January 1, 1970 UTC.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class NowFunction extends FunctionNode {
 
@@ -15,7 +17,17 @@ public class NowFunction extends FunctionNode {
      * Constructs a new instance of this class.
      */
     public NowFunction() {
-        super("now", Collections.<GroupingExpression>emptyList());
+        this(null, null);
     }
+
+    private NowFunction(String label, Integer level) {
+        super("now", label, level, Collections.emptyList());
+    }
+
+    @Override
+    public NowFunction copy() {
+        return new NowFunction(getLabel(), getLevelOrNull());
+    }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/OrFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/OrFunction.java
index ad1809f312f..43456a4f281 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/OrFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/OrFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents an or-function in a {@link GroupingExpression}. It evaluates to a long that equals the result
  * of or'ing the results of all arguments together in the order they were given to the constructor.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class OrFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class OrFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a long.
      */
     public OrFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private OrFunction(List<GroupingExpression> args) {
-        super("or", args);
+    private OrFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("or", label, level, args);
+    }
+
+    @Override
+    public OrFunction copy() {
+        return new OrFunction(getLabel(),
+                              getLevelOrNull(),
+                              args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,7 +46,7 @@ public class OrFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new OrFunction(args);
+        return new OrFunction(null, null, args);
     }
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/PredefinedFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/PredefinedFunction.java
index ebae4b238b4..5818c5034b6 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/PredefinedFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/PredefinedFunction.java
@@ -4,6 +4,7 @@ package com.yahoo.search.grouping.request;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a predefined bucket-function in a {@link GroupingExpression}. It maps the input into one of the
@@ -13,8 +14,8 @@ import java.util.List;
  */
 public abstract class PredefinedFunction extends FunctionNode {
 
-    protected PredefinedFunction(GroupingExpression exp, List<? extends BucketValue> args) {
-        super("predefined", asList(exp, args));
+    protected PredefinedFunction(String label, Integer level, GroupingExpression exp, List<? extends BucketValue> args) {
+        super("predefined", label, level, asList(exp, args));
         Iterator<? extends BucketValue> it = args.iterator();
         BucketValue prev = it.next();
         while (it.hasNext()) {
@@ -47,12 +48,12 @@ public abstract class PredefinedFunction extends FunctionNode {
         return (BucketValue)getArg(i + 1);
     }
 
-    private static
-    List<GroupingExpression> asList(GroupingExpression exp, List<? extends BucketValue> args) {
+    private static List<GroupingExpression> asList(GroupingExpression exp, List<? extends BucketValue> args) {
         List<GroupingExpression> ret = new LinkedList<>();
         ret.add(exp);
         ret.addAll(args);
         return ret;
     }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/RawBucket.java b/container-search/src/main/java/com/yahoo/search/grouping/request/RawBucket.java
index 32be9233445..415dbe2adff 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/RawBucket.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/RawBucket.java
@@ -4,7 +4,7 @@ package com.yahoo.search.grouping.request;
 /**
  * This class represents a {@link RawValue} bucket in a {@link PredefinedFunction}.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
  */
 public class RawBucket extends BucketValue {
 
@@ -25,7 +25,7 @@ public class RawBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public RawBucket(RawBuffer from, RawBuffer to) {
-        super(new RawValue(from), new RawValue(to));
+        super(null, null, new RawValue(from), new RawValue(to));
     }
 
     /**
@@ -35,6 +35,16 @@ public class RawBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public RawBucket(ConstantValue<?> from, ConstantValue<?> to) {
-        super(from, to);
+        super(null, null, from, to);
     }
+
+    private RawBucket(String label, Integer level, ConstantValue<?> from, ConstantValue<?> to) {
+        super(label, level, from, to);
+    }
+
+    @Override
+    public RawBucket copy() {
+        return new RawBucket(getLabel(), getLevelOrNull(), getFrom().copy(), getTo().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/RawBuffer.java b/container-search/src/main/java/com/yahoo/search/grouping/request/RawBuffer.java
index 460c547f1d6..9b18d7b374c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/RawBuffer.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/RawBuffer.java
@@ -7,9 +7,10 @@ import java.util.ArrayList;
  * This class represents a buffer of byte values to be used as a backing buffer
  * for raw buckets.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
  */
 public class RawBuffer implements Comparable<RawBuffer>, Cloneable {
+
     private final ArrayList<Byte> buffer;
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/RawPredefined.java b/container-search/src/main/java/com/yahoo/search/grouping/request/RawPredefined.java
index 7f27a428e74..567892a0377 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/RawPredefined.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/RawPredefined.java
@@ -2,12 +2,13 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a predefined bucket-function in a {@link GroupingExpression} for expressions that evaluate to a
  * raw.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
  */
 public class RawPredefined extends PredefinedFunction {
 
@@ -19,11 +20,23 @@ public class RawPredefined extends PredefinedFunction {
      * @param argN The optional buckets.
      */
     public RawPredefined(GroupingExpression exp, RawBucket arg1, RawBucket... argN) {
-        this(exp, asList(arg1, argN));
+        this(null, null, exp, asList(arg1, argN));
     }
 
-    private RawPredefined(GroupingExpression exp, List<RawBucket> args) {
-        super(exp, args);
+    private RawPredefined(String label, Integer level, GroupingExpression exp, List<RawBucket> args) {
+        super(label, level, exp, args);
+    }
+
+    @Override
+    public RawPredefined copy() {
+        return new RawPredefined(getLabel(),
+                                 getLevelOrNull(),
+                                 getArg(0),
+                                 args().stream()
+                                       .skip(1)
+                                       .map(RawBucket.class::cast)
+                                       .map(arg -> arg.copy())
+                                       .collect(Collectors.toList()));
     }
 
     @Override
@@ -43,6 +56,6 @@ public class RawPredefined extends PredefinedFunction {
         if (args.isEmpty()) {
             throw new IllegalArgumentException("Expected at least one bucket, got none.");
         }
-        return new RawPredefined(exp, args);
+        return new RawPredefined(null, null, exp, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/RawValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/RawValue.java
index f66ee362599..c8215b1b389 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/RawValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/RawValue.java
@@ -4,7 +4,8 @@ package com.yahoo.search.grouping.request;
 /**
  * This class represents a raw value in a {@link GroupingExpression}.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
+ * @author bratseth
  */
 public class RawValue extends ConstantValue<RawBuffer> {
 
@@ -14,6 +15,16 @@ public class RawValue extends ConstantValue<RawBuffer> {
      * @param value The immutable value to assign to this.
      */
     public RawValue(RawBuffer value) {
-        super(value);
+        super(null, null, value);
     }
+
+    private RawValue(String label, Integer level, RawBuffer value) {
+        super(label, level, value);
+    }
+
+    @Override
+    public RawValue copy() {
+        return new RawValue(getLabel(), getLevelOrNull(), getValue().clone());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/RelevanceValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/RelevanceValue.java
index 01735c0bdab..30cdf2c6f5c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/RelevanceValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/RelevanceValue.java
@@ -6,6 +6,7 @@ package com.yahoo.search.grouping.request;
  * the input {@link com.yahoo.search.result.Hit}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class RelevanceValue extends DocumentValue {
 
@@ -13,7 +14,16 @@ public class RelevanceValue extends DocumentValue {
      * Constructs a new instance of this class.
      */
     public RelevanceValue() {
-        super("relevance()");
+        this(null, null);
+    }
+
+    private RelevanceValue(String label, Integer level) {
+        super("relevance()", label, level);
+    }
+
+    @Override
+    public RelevanceValue copy() {
+        return new RelevanceValue(getLabel(), getLevelOrNull());
     }
 
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ReverseFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ReverseFunction.java
index 8283806b5c1..8937018c28f 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ReverseFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ReverseFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * result of the argument, sorted in descending order.
  *
  * @author baldersheim
+ * @author bratseth
  */
 public class ReverseFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class ReverseFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a list.
      */
     public ReverseFunction(GroupingExpression exp) {
-        super("reverse", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private ReverseFunction(String label, Integer level, GroupingExpression exp) {
+        super("reverse", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public ReverseFunction copy() {
+        return new ReverseFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/SecondOfMinuteFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/SecondOfMinuteFunction.java
index b83065af629..7b01d820d89 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/SecondOfMinuteFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/SecondOfMinuteFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * that equals the second of minute (0-59) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class SecondOfMinuteFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class SecondOfMinuteFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public SecondOfMinuteFunction(GroupingExpression exp) {
-        super("time.secondofminute", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private SecondOfMinuteFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.secondofminute", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public SecondOfMinuteFunction copy() {
+        return new SecondOfMinuteFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/SizeFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/SizeFunction.java
index 4b7055ffb89..a9deb2b8e64 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/SizeFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/SizeFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * number of elements in the result of the argument (e.g. the number of elements in an array).
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class SizeFunction extends FunctionNode {
 
@@ -17,7 +18,17 @@ public class SizeFunction extends FunctionNode {
      * @param exp The expression to evaluate.
      */
     public SizeFunction(GroupingExpression exp) {
-        super("size", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private SizeFunction(String label, Integer level, GroupingExpression exp) {
+        super("size", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public SizeFunction copy() {
+        return new SizeFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/SortFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/SortFunction.java
index 6ee4644344e..57489b8ee1a 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/SortFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/SortFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * result of the argument, sorted in ascending order.
  *
  * @author baldersheim
+ * @author bratseth
  */
 public class SortFunction  extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class SortFunction  extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a list.
      */
     public SortFunction(GroupingExpression exp) {
-        super("sort", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private SortFunction(String label, Integer level, GroupingExpression exp) {
+        super("sort", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public SortFunction copy() {
+        return new SortFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/StandardDeviationAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/StandardDeviationAggregator.java
index 62bc0085422..d96b840dde9 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/StandardDeviationAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/StandardDeviationAggregator.java
@@ -6,13 +6,26 @@ package com.yahoo.search.grouping.request;
  * of the values that the contained expression evaluated to over all the inputs.
  *
  * @author bjorncs
+ * @author bratseth
  */
 public class StandardDeviationAggregator extends AggregatorNode {
 
     /**
-     * @param exp The expression to aggregate on.
+     * Constructs a new instance of this class.
+     *
+     * @param expression the expression to aggregate on.
      */
-    public StandardDeviationAggregator(GroupingExpression exp) {
-        super("stddev", exp);
+    public StandardDeviationAggregator(GroupingExpression expression) {
+        this(null, null, expression);
     }
+
+    private StandardDeviationAggregator(String label, Integer level, GroupingExpression expression) {
+        super("stddev", label, level, expression);
+    }
+
+    @Override
+    public StandardDeviationAggregator copy() {
+        return new StandardDeviationAggregator(getLabel(), getLevelOrNull(), getExpression().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/StrCatFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/StrCatFunction.java
index 97dcc909254..3b266b884bf 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/StrCatFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/StrCatFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a strcat-function in a {@link GroupingExpression}. It evaluates to a string that equals the
  * contatenation of the string results of all arguments in the order they were given to the constructor.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class StrCatFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class StrCatFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a string.
      */
     public StrCatFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private StrCatFunction(List<GroupingExpression> args) {
-        super("strcat", args);
+    private StrCatFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("strcat", label, level, args);
+    }
+
+    @Override
+    public StrCatFunction copy() {
+        return new StrCatFunction(getLabel(),
+                                  getLevelOrNull(),
+                                  args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,7 +46,7 @@ public class StrCatFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new StrCatFunction(args);
+        return new StrCatFunction(null, null, args);
     }
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/StrLenFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/StrLenFunction.java
index e9ca48b3db3..d784e37b337 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/StrLenFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/StrLenFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * number of bytes in the string result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class StrLenFunction extends FunctionNode {
 
@@ -17,7 +18,17 @@ public class StrLenFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a string.
      */
     public StrLenFunction(GroupingExpression exp) {
-        super("strlen", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private StrLenFunction(String label, Integer level, GroupingExpression exp) {
+        super("strlen", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public StrLenFunction copy() {
+        return new StrLenFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/StringBucket.java b/container-search/src/main/java/com/yahoo/search/grouping/request/StringBucket.java
index 80e85ed9e78..5558f1443db 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/StringBucket.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/StringBucket.java
@@ -25,7 +25,7 @@ public class StringBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public StringBucket(String from, String to) {
-        super(new StringValue(from), new StringValue(to));
+        super(null, null, new StringValue(from), new StringValue(to));
     }
 
     /**
@@ -35,6 +35,16 @@ public class StringBucket extends BucketValue {
      * @param to            The to-value to assign to this.
      */
     public StringBucket(ConstantValue<?> from, ConstantValue<?> to) {
-        super(from, to);
+        super(null, null, from, to);
     }
+
+    private StringBucket(String label, Integer level, ConstantValue<?> from, ConstantValue<?> to) {
+        super(label, level, from, to);
+    }
+
+    @Override
+    public StringBucket copy() {
+        return new StringBucket(getLabel(), getLevelOrNull(), getFrom().copy(), getTo().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/StringPredefined.java b/container-search/src/main/java/com/yahoo/search/grouping/request/StringPredefined.java
index 465ff96157d..cae9bc113c9 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/StringPredefined.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/StringPredefined.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a predefined bucket-function in a {@link GroupingExpression} for expressions that evaluate to a
@@ -19,11 +20,23 @@ public class StringPredefined extends PredefinedFunction {
      * @param argN The optional buckets.
      */
     public StringPredefined(GroupingExpression exp, StringBucket arg1, StringBucket... argN) {
-        this(exp, asList(arg1, argN));
+        this(null, null, exp, asList(arg1, argN));
     }
 
-    private StringPredefined(GroupingExpression exp, List<StringBucket> args) {
-        super(exp, args);
+    private StringPredefined(String label, Integer level, GroupingExpression exp, List<StringBucket> args) {
+        super(label, level, exp, args);
+    }
+
+    @Override
+    public StringPredefined copy() {
+        return new StringPredefined(getLabel(),
+                                    getLevelOrNull(),
+                                    getArg(0),
+                                    args().stream()
+                                          .skip(1)
+                                          .map(StringBucket.class::cast)
+                                          .map(arg -> arg.copy())
+                                          .collect(Collectors.toList()));
     }
 
     @Override
@@ -43,6 +56,6 @@ public class StringPredefined extends PredefinedFunction {
         if (args.isEmpty()) {
             throw new IllegalArgumentException("Expected at least one bucket, got none.");
         }
-        return new StringPredefined(exp, args);
+        return new StringPredefined(null, null, exp, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/StringValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/StringValue.java
index 4fc630c7b1b..473e6b73f95 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/StringValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/StringValue.java
@@ -5,6 +5,7 @@ package com.yahoo.search.grouping.request;
  * This class represents a constant {@link String} value in a {@link GroupingExpression}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class StringValue extends ConstantValue<String> {
 
@@ -14,6 +15,16 @@ public class StringValue extends ConstantValue<String> {
      * @param value The immutable value to assign to this.
      */
     public StringValue(String value) {
-        super(value);
+        super(null, null, value);
     }
+
+    private StringValue(String label, Integer level, String value) {
+        super(label, level, value);
+    }
+
+    @Override
+    public StringValue copy() {
+        return new StringValue(getLabel(), getLevelOrNull(), getValue());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/SubFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/SubFunction.java
index 1d0456ffcf2..e0fe533e361 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/SubFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/SubFunction.java
@@ -2,6 +2,7 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents a div-function in a {@link GroupingExpression}. It evaluates to a number that equals the result
@@ -20,11 +21,18 @@ public class SubFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a number.
      */
     public SubFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private SubFunction(List<GroupingExpression> args) {
-        super("sub", args);
+    private SubFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("sub", label, level, args);
+    }
+
+    @Override
+    public SubFunction copy() {
+        return new SubFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -38,6 +46,6 @@ public class SubFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new SubFunction(args);
+        return new SubFunction(null, null, args);
     }
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/SumAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/SumAggregator.java
index b50dd84e27e..0b34b0660d5 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/SumAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/SumAggregator.java
@@ -6,15 +6,26 @@ package com.yahoo.search.grouping.request;
  * the contained expression evaluated to over all the inputs.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class SumAggregator extends AggregatorNode {
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param exp The expression to aggregate on.
+     * @param expression the expression to aggregate on.
      */
-    public SumAggregator(GroupingExpression exp) {
-        super("sum", exp);
+    public SumAggregator(GroupingExpression expression) {
+        this(null, null, expression);
     }
+
+    private SumAggregator(String label, Integer level, GroupingExpression expression) {
+        super("sum", label, level, expression);
+    }
+
+    @Override
+    public SumAggregator copy() {
+        return new SumAggregator(getLabel(), getLevelOrNull(), getExpression().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/SummaryValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/SummaryValue.java
index 6cdaa3b2e4a..68641d6e6e6 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/SummaryValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/SummaryValue.java
@@ -15,8 +15,7 @@ public class SummaryValue extends DocumentValue {
      * Constructs a new instance of this class, using the default summary class.
      */
     public SummaryValue() {
-        super("summary()");
-        name = null;
+        this(null, null, null);
     }
 
     /**
@@ -25,10 +24,19 @@ public class SummaryValue extends DocumentValue {
      * @param summaryName The name of the summary class to assign to this.
      */
     public SummaryValue(String summaryName) {
-        super("summary(" + summaryName + ")");
+        this(null, null, summaryName);
+    }
+
+    private SummaryValue(String label, Integer level, String summaryName) {
+        super("summary(" + (summaryName == null ? "" : summaryName)  + ")", label, level);
         name = summaryName;
     }
 
+    @Override
+    public SummaryValue copy() {
+        return new SummaryValue(getLabel(), getLevelOrNull(), getSummaryName());
+    }
+
     /**
      * Returns the name of the summary class used to retrieve the hit from the search node.
      *
@@ -37,4 +45,5 @@ public class SummaryValue extends DocumentValue {
     public String getSummaryName() {
         return name;
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ToDoubleFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ToDoubleFunction.java
index c6816dda621..8e7490d0cc6 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ToDoubleFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ToDoubleFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * a double. If the argument can not be converted, this function returns 0.
  *
  * @author baldersheim
+ * @author bratseth
  */
 public class ToDoubleFunction extends FunctionNode {
 
@@ -17,6 +18,18 @@ public class ToDoubleFunction extends FunctionNode {
      * @param exp The expression to evaluate.
      */
     public ToDoubleFunction(GroupingExpression exp) {
-        super("todouble", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private ToDoubleFunction(String label, Integer level, GroupingExpression exp) {
+        super("todouble", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public ToDoubleFunction copy() {
+        return new ToDoubleFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
+
+
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ToLongFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ToLongFunction.java
index c513fbd76e6..77470487a6e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ToLongFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ToLongFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * long. If the argument can not be converted, this function returns 0.
  *
  * @author baldersheim
+ * @author bratseth
  */
 public class ToLongFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class ToLongFunction extends FunctionNode {
      * @param exp The expression to evaluate.
      */
     public ToLongFunction(GroupingExpression exp) {
-        super("tolong", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private ToLongFunction(String label, Integer level, GroupingExpression exp) {
+        super("tolong", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public ToLongFunction copy() {
+        return new ToLongFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ToRawFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ToRawFunction.java
index 3c1c335b8ef..2f32b0fe139 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ToRawFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ToRawFunction.java
@@ -8,7 +8,8 @@ import java.util.Arrays;
  * converts the result of the argument to a raw type. If the argument can not
  * be converted, this function returns null.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
+ * @author bratseth
  */
 public class ToRawFunction extends FunctionNode {
 
@@ -18,6 +19,16 @@ public class ToRawFunction extends FunctionNode {
      * @param exp The expression to evaluate.
      */
     public ToRawFunction(GroupingExpression exp) {
-        super("toraw", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private ToRawFunction(String label, Integer level, GroupingExpression exp) {
+        super("toraw", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public ToRawFunction copy() {
+        return new ToRawFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ToStringFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ToStringFunction.java
index 7f4e48c8d81..dd7bd0b5250 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ToStringFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ToStringFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * long. If the argument can not be converted, this function returns 0.
  *
  * @author baldersheim
+ * @author bratseth
  */
 public class ToStringFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class ToStringFunction extends FunctionNode {
      * @param exp The expression to evaluate.
      */
     public ToStringFunction(GroupingExpression exp) {
-        super("tostring", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private ToStringFunction(String label, Integer level, GroupingExpression exp) {
+        super("tostring", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public ToStringFunction copy() {
+        return new ToStringFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/UcaFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/UcaFunction.java
index 2efecc235ac..787d7aa5863 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/UcaFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/UcaFunction.java
@@ -2,18 +2,20 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents an uca-function in a {@link GroupingExpression}.
  *
- * @author <a href="mailto:lulf@yahoo-inc.com">Ulf Lilleengen</a>
+ * @author Ulf Lilleengen
+ * @author bratseth
  */
 public class UcaFunction extends FunctionNode {
 
     private final String locale;
     private final String strength;
 
-
     /**
      * Constructs a new instance of this class.
      *
@@ -21,9 +23,7 @@ public class UcaFunction extends FunctionNode {
      * @param locale  The locale to used for sorting.
      */
     public UcaFunction(GroupingExpression exp, String locale) {
-        super("uca", Arrays.asList(exp, new StringValue(locale)));
-        this.locale = locale;
-        this.strength = "TERTIARY";
+        this(null, null, Arrays.asList(exp, new StringValue(locale)));
     }
 
     /**
@@ -34,12 +34,22 @@ public class UcaFunction extends FunctionNode {
      * @param strength The strength level to use.
      */
     public UcaFunction(GroupingExpression exp, String locale, String strength) {
-        super("uca", Arrays.asList(exp, new StringValue(locale), new StringValue(strength)));
-        if (!validStrength(strength)) {
+        this(null, null, Arrays.asList(exp, new StringValue(locale), new StringValue(strength)));
+        if ( ! validStrength(strength))
             throw new IllegalArgumentException("Not a valid UCA strength: " + strength);
-        }
-        this.locale = locale;
-        this.strength = strength;
+    }
+
+    private UcaFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("uca", label, level, args);
+        this.locale = ((StringValue)args.get(1)).getValue();
+        this.strength = args.size() > 2 ? ((StringValue)args.get(1)).getValue() : "TERTIARY";
+    }
+
+    @Override
+    public UcaFunction copy() {
+        return new UcaFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     private boolean validStrength(String strength) {
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/XorAggregator.java b/container-search/src/main/java/com/yahoo/search/grouping/request/XorAggregator.java
index 18ce7abd96c..e68303b564c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/XorAggregator.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/XorAggregator.java
@@ -6,15 +6,26 @@ package com.yahoo.search.grouping.request;
  * the contained expression evaluated to over all the inputs.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class XorAggregator extends AggregatorNode {
 
     /**
      * Constructs a new instance of this class.
      *
-     * @param exp The expression to aggregate on.
+     * @param expression the expression to aggregate on.
      */
-    public XorAggregator(GroupingExpression exp) {
-        super("xor", exp);
+    public XorAggregator(GroupingExpression expression) {
+        this(null, null, expression);
     }
+
+    private XorAggregator(String label, Integer level, GroupingExpression expression) {
+        super("xor", label, level, expression);
+    }
+
+    @Override
+    public XorAggregator copy() {
+        return new XorAggregator(getLabel(), getLevelOrNull(), getExpression().copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/XorBitFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/XorBitFunction.java
index 2f6061a3aa2..8fdd2dc5839 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/XorBitFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/XorBitFunction.java
@@ -2,12 +2,15 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents an xor-function in a {@link GroupingExpression}. It evaluates to a long that equals the xor of
  * 'width' bits over the binary representation of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class XorBitFunction extends FunctionNode {
 
@@ -18,7 +21,18 @@ public class XorBitFunction extends FunctionNode {
      * @param numBits The number of bits of the expression value to xor.
      */
     public XorBitFunction(GroupingExpression exp, int numBits) {
-        super("xorbit", Arrays.asList(exp, new LongValue(numBits)));
+        this(null, null, Arrays.asList(exp, new LongValue(numBits)));
+    }
+
+    private XorBitFunction(String label, Integer level, List<GroupingExpression> exp) {
+        super("xorbit", label, level, exp);
+    }
+
+    @Override
+    public XorBitFunction copy() {
+        return new XorBitFunction(getLabel(),
+                                  getLevelOrNull(),
+                                  args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/XorFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/XorFunction.java
index c3a5f5d88ad..a7a1e4d2a8f 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/XorFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/XorFunction.java
@@ -2,12 +2,14 @@
 package com.yahoo.search.grouping.request;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * This class represents an xor-function in a {@link GroupingExpression}. It evaluates to a long that equals the result
  * of and'ing the results of all arguments together in the order they were given to the constructor.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class XorFunction extends FunctionNode {
 
@@ -19,11 +21,18 @@ public class XorFunction extends FunctionNode {
      * @param argN The optional arguments, must evaluate to a long.
      */
     public XorFunction(GroupingExpression arg1, GroupingExpression arg2, GroupingExpression... argN) {
-        this(asList(arg1, arg2, argN));
+        this(null, null, asList(arg1, arg2, argN));
     }
 
-    private XorFunction(List<GroupingExpression> args) {
-        super("xor", args);
+    private XorFunction(String label, Integer level, List<GroupingExpression> args) {
+        super("xor", label, level, args);
+    }
+
+    @Override
+    public XorFunction copy() {
+        return new XorFunction(getLabel(),
+                               getLevelOrNull(),
+                               args().stream().map(arg -> arg.copy()).collect(Collectors.toList()));
     }
 
     /**
@@ -37,7 +46,7 @@ public class XorFunction extends FunctionNode {
         if (args.size() < 2) {
             throw new IllegalArgumentException("Expected 2 or more arguments, got " + args.size() + ".");
         }
-        return new XorFunction(args);
+        return new XorFunction(null, null, args);
     }
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/YearFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/YearFunction.java
index 5bda8231929..737597a585c 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/YearFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/YearFunction.java
@@ -8,6 +8,7 @@ import java.util.Arrays;
  * the full year (e.g. 2010) of the result of the argument.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class YearFunction extends FunctionNode {
 
@@ -17,6 +18,16 @@ public class YearFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long.
      */
     public YearFunction(GroupingExpression exp) {
-        super("time.year", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private YearFunction(String label, Integer level, GroupingExpression exp) {
+        super("time.year", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public YearFunction copy() {
+        return new YearFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/YmumValue.java b/container-search/src/main/java/com/yahoo/search/grouping/request/YmumValue.java
index c5749c4673d..8ca772b9188 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/YmumValue.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/YmumValue.java
@@ -6,6 +6,7 @@ package com.yahoo.search.grouping.request;
  * input {@link com.yahoo.search.result.Hit}.
  *
  * @author Simon Thoresen Hult
+ * @author bratseth
  */
 public class YmumValue extends DocumentValue {
 
@@ -13,7 +14,17 @@ public class YmumValue extends DocumentValue {
      * Constructs a new instance of this class.
      */
     public YmumValue() {
-        super("ymum()");
+        this(null, null);
     }
+
+    private YmumValue(String label, Integer level) {
+        super("ymum()", label, level);
+    }
+
+    @Override
+    public YmumValue copy() {
+        return new YmumValue(getLabel(), getLevelOrNull());
+    }
+
 }
 
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveXFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveXFunction.java
index bcd6f2ba71a..5ab057ef8a8 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveXFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveXFunction.java
@@ -5,14 +5,26 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class ZCurveXFunction extends FunctionNode {
+
     /**
      * Constructs a new instance of this class.
      *
      * @param exp The expression to evaluate, must evaluate to a long or long[].
      */
     public ZCurveXFunction(GroupingExpression exp) {
-        super("zcurve.x", Arrays.asList(exp));
+        this(null, null, exp);
+    }
+
+    private ZCurveXFunction(String label, Integer level, GroupingExpression exp) {
+        super("zcurve.x", label, level, Arrays.asList(exp));
     }
+
+    @Override
+    public ZCurveXFunction copy() {
+        return new ZCurveXFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveYFunction.java b/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveYFunction.java
index 57c55d41209..fa645eb9141 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveYFunction.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/request/ZCurveYFunction.java
@@ -5,6 +5,7 @@ import java.util.Arrays;
 
 /**
  * @author baldersheim
+ * @author bratseth
  */
 public class ZCurveYFunction extends FunctionNode {
     /**
@@ -13,6 +14,16 @@ public class ZCurveYFunction extends FunctionNode {
      * @param exp The expression to evaluate, must evaluate to a long or long[].
      */
     public ZCurveYFunction(GroupingExpression exp) {
-        super("zcurve.y", Arrays.asList(exp));
+        this(null, null, exp);
     }
+
+    private ZCurveYFunction(String label, Integer level, GroupingExpression exp) {
+        super("zcurve.y", label, level, Arrays.asList(exp));
+    }
+
+    @Override
+    public ZCurveYFunction copy() {
+        return new ZCurveYFunction(getLabel(), getLevelOrNull(), getArg(0).copy());
+    }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/vespa/CompositeContinuation.java b/container-search/src/main/java/com/yahoo/search/grouping/vespa/CompositeContinuation.java
index a02b80db16f..7a12a200f5b 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/vespa/CompositeContinuation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/vespa/CompositeContinuation.java
@@ -10,10 +10,17 @@ import java.util.List;
 /**
  * @author Simon Thoresen Hult
  */
-class CompositeContinuation extends EncodableContinuation implements Iterable<EncodableContinuation> {
+final class CompositeContinuation extends EncodableContinuation implements Iterable<EncodableContinuation> {
 
     private final List<EncodableContinuation> children = new ArrayList<>();
 
+    @Override
+    public CompositeContinuation copy() {
+        CompositeContinuation copy = new CompositeContinuation();
+        this.children.forEach(child -> copy.add(child.copy()));
+        return copy;
+    }
+
     public CompositeContinuation add(EncodableContinuation child) {
         children.add(child);
         return this;
@@ -48,4 +55,5 @@ class CompositeContinuation extends EncodableContinuation implements Iterable<En
         }
         return ret;
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/vespa/EncodableContinuation.java b/container-search/src/main/java/com/yahoo/search/grouping/vespa/EncodableContinuation.java
index 2ec371475c2..df24b7129ff 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/vespa/EncodableContinuation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/vespa/EncodableContinuation.java
@@ -11,9 +11,13 @@ abstract class EncodableContinuation extends Continuation {
     public abstract void encode(IntegerEncoder out);
 
     @Override
+    public abstract EncodableContinuation copy();
+
+    @Override
     public final String toString() {
         IntegerEncoder encoder = new IntegerEncoder();
         encode(encoder);
         return encoder.toString();
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/vespa/GroupingExecutor.java b/container-search/src/main/java/com/yahoo/search/grouping/vespa/GroupingExecutor.java
index 2b3f80a4b8f..61856467652 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/vespa/GroupingExecutor.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/vespa/GroupingExecutor.java
@@ -70,26 +70,19 @@ public class GroupingExecutor extends Searcher {
     @Override
     public Result search(Query query, Execution execution) {
         String error = QueryCanonicalizer.canonicalize(query);
-        if (error != null) {
-            return new Result(query, ErrorMessage.createIllegalQuery(error));
-        }
+        if (error != null) return new Result(query, ErrorMessage.createIllegalQuery(error));
+
         query.prepare();
 
-        // Retrieve grouping requests from query.
-        List<GroupingRequest> reqList = GroupingRequest.getRequests(query);
-        if (reqList.isEmpty()) {
-            return execution.search(query);
-        }
+        if (query.getSelect().getGrouping().isEmpty()) return execution.search(query);
 
         // Convert requests to Vespa style grouping.
         Map<Integer, Grouping> groupingMap = new HashMap<>();
         List<RequestContext> requestContextList = new LinkedList<>();
-        for (GroupingRequest grpRequest : reqList) {
-            requestContextList.add(convertRequest(query, grpRequest, groupingMap));
-        }
-        if (groupingMap.isEmpty()) {
-            return execution.search(query);
-        }
+        for (int i = 0; i < query.getSelect().getGrouping().size(); i++)
+            requestContextList.add(convertRequest(query, query.getSelect().getGrouping().get(i), i, groupingMap));
+
+        if (groupingMap.isEmpty()) return execution.search(query);
 
         // Perform the necessary passes to execute grouping.
         Result result = performSearch(query, execution, groupingMap);
@@ -157,8 +150,8 @@ public class GroupingExecutor extends Searcher {
      * @param map   The grouping map to write to.
      * @return The context required to identify the request results.
      */
-    private RequestContext convertRequest(Query query, GroupingRequest req, Map<Integer, Grouping> map) {
-        RequestBuilder builder = new RequestBuilder(req.getRequestId());
+    private RequestContext convertRequest(Query query, GroupingRequest req, int requestId, Map<Integer, Grouping> map) {
+        RequestBuilder builder = new RequestBuilder(requestId);
         builder.setRootOperation(req.getRootOperation());
         builder.setDefaultSummaryName(query.getPresentation().getSummary());
         builder.setTimeZone(req.getTimeZone());
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/vespa/OffsetContinuation.java b/container-search/src/main/java/com/yahoo/search/grouping/vespa/OffsetContinuation.java
index 6adec94132e..324f3eb0b6e 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/vespa/OffsetContinuation.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/vespa/OffsetContinuation.java
@@ -20,6 +20,11 @@ class OffsetContinuation extends EncodableContinuation {
         this.flags = flags;
     }
 
+    @Override
+    public OffsetContinuation copy() {
+        return this; // immutable
+    }
+
     public ResultId getResultId() {
         return resultId;
     }
@@ -81,4 +86,5 @@ class OffsetContinuation extends EncodableContinuation {
         int flags = in.next();
         return new OffsetContinuation(resultId, tag, offset, flags);
     }
+
 }
diff --git a/container-search/src/main/java/com/yahoo/search/grouping/vespa/ResultId.java b/container-search/src/main/java/com/yahoo/search/grouping/vespa/ResultId.java
index 0d09e7ab69d..82784bcf9dd 100644
--- a/container-search/src/main/java/com/yahoo/search/grouping/vespa/ResultId.java
+++ b/container-search/src/main/java/com/yahoo/search/grouping/vespa/ResultId.java
@@ -4,6 +4,8 @@ package com.yahoo.search.grouping.vespa;
 import java.util.Arrays;
 
 /**
+ * Immutable
+ *
  * @author Simon Thoresen Hult
  */
 class ResultId {