Add feature flag for unordered merge chaining

6 files changed, 43 insertions, 2 deletions

diff --git a/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java b/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
index b027a3bd51e..2b2344c5fdb 100644
--- a/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
+++ b/config-model-api/src/main/java/com/yahoo/config/model/api/ModelContext.java
@@ -106,6 +106,7 @@ public interface ModelContext {
         @ModelFeatureFlag(owners = {"arnej"}) default boolean forwardIssuesAsErrors() { return true; }
         @ModelFeatureFlag(owners = {"geirst", "vekterli"}) default boolean asyncApplyBucketDiff() { return false; }
         @ModelFeatureFlag(owners = {"arnej"}) default boolean ignoreThreadStackSizes() { return false; }
+        @ModelFeatureFlag(owners = {"vekterli", "geirst"}) default boolean unorderedMergeChaining() { return false; }
     }
 
     /** Warning: As elsewhere in this package, do not make backwards incompatible changes that will break old config models! */
diff --git a/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java b/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
index 49c968a1d91..9f2f3620c73 100644
--- a/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
+++ b/config-model/src/main/java/com/yahoo/config/model/deploy/TestProperties.java
@@ -72,6 +72,7 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
     private double diskBloatFactor = 0.2;
     private boolean distributorEnhancedMaintenanceScheduling = false;
     private boolean asyncApplyBucketDiff = false;
+    private boolean unorderedMergeChaining = false;
     private List<String> zoneDnsSuffixes = List.of();
 
     @Override public ModelContext.FeatureFlags featureFlags() { return this; }
@@ -125,6 +126,7 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
     @Override public boolean distributorEnhancedMaintenanceScheduling() { return distributorEnhancedMaintenanceScheduling; }
     @Override public int maxUnCommittedMemory() { return maxUnCommittedMemory; }
     @Override public boolean asyncApplyBucketDiff() { return asyncApplyBucketDiff; }
+    @Override public boolean unorderedMergeChaining() { return unorderedMergeChaining; }
     @Override public List<String> zoneDnsSuffixes() { return zoneDnsSuffixes; }
 
     public TestProperties maxUnCommittedMemory(int maxUnCommittedMemory) {
@@ -322,6 +324,11 @@ public class TestProperties implements ModelContext.Properties, ModelContext.Fea
         return this;
     }
 
+    public TestProperties setUnorderedMergeChaining(boolean unordered) {
+        unorderedMergeChaining = unordered;
+        return this;
+    }
+
     public TestProperties setZoneDnsSuffixes(List<String> zoneDnsSuffixes) {
         this.zoneDnsSuffixes = List.copyOf(zoneDnsSuffixes);
         return this;
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java b/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java
index fa91dbc2e42..518c3f73a8f 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/content/DistributorCluster.java
@@ -45,6 +45,7 @@ public class DistributorCluster extends AbstractConfigProducer<Distributor> impl
     private final int maxActivationInhibitedOutOfSyncGroups;
     private final int mergeBusyWait;
     private final boolean enhancedMaintenanceScheduling;
+    private final boolean unorderedMergeChaining;
 
     public static class Builder extends VespaDomBuilder.DomConfigProducerBuilder<DistributorCluster> {
 
@@ -109,12 +110,14 @@ public class DistributorCluster extends AbstractConfigProducer<Distributor> impl
             int maxInhibitedGroups = deployState.getProperties().featureFlags().maxActivationInhibitedOutOfSyncGroups();
             int mergeBusyWait = deployState.getProperties().featureFlags().distributorMergeBusyWait();
             boolean useEnhancedMaintenanceScheduling = deployState.getProperties().featureFlags().distributorEnhancedMaintenanceScheduling();
+            boolean unorderedMergeChaining = deployState.getProperties().featureFlags().unorderedMergeChaining();
 
             return new DistributorCluster(parent,
                     new BucketSplitting.Builder().build(new ModelElement(producerSpec)), gc,
                     hasIndexedDocumentType, useThreePhaseUpdates,
                     maxInhibitedGroups, mergeBusyWait,
-                    useEnhancedMaintenanceScheduling);
+                    useEnhancedMaintenanceScheduling,
+                    unorderedMergeChaining);
         }
     }
 
@@ -123,7 +126,8 @@ public class DistributorCluster extends AbstractConfigProducer<Distributor> impl
                                boolean useThreePhaseUpdates,
                                int maxActivationInhibitedOutOfSyncGroups,
                                int mergeBusyWait,
-                               boolean enhancedMaintenanceScheduling)
+                               boolean enhancedMaintenanceScheduling,
+                               boolean unorderedMergeChaining)
     {
         super(parent, "distributor");
         this.parent = parent;
@@ -134,6 +138,7 @@ public class DistributorCluster extends AbstractConfigProducer<Distributor> impl
         this.maxActivationInhibitedOutOfSyncGroups = maxActivationInhibitedOutOfSyncGroups;
         this.mergeBusyWait = mergeBusyWait;
         this.enhancedMaintenanceScheduling = enhancedMaintenanceScheduling;
+        this.unorderedMergeChaining = unorderedMergeChaining;
     }
 
     @Override
@@ -149,6 +154,7 @@ public class DistributorCluster extends AbstractConfigProducer<Distributor> impl
         builder.max_activation_inhibited_out_of_sync_groups(maxActivationInhibitedOutOfSyncGroups);
         builder.inhibit_merge_sending_on_busy_node_duration_sec(mergeBusyWait);
         builder.implicitly_clear_bucket_priority_on_schedule(enhancedMaintenanceScheduling);
+        builder.use_unordered_merge_chaining(unorderedMergeChaining);
 
         bucketSplitting.getConfig(builder);
     }
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java b/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java
index 0fb7e82c095..729348a0e3a 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/content/ContentClusterTest.java
@@ -1119,6 +1119,23 @@ public class ContentClusterTest extends ContentBaseTest {
     }
 
     @Test
+    public void unordered_merge_chaining_config_controlled_by_properties() throws Exception {
+        assertFalse(resolveUnorderedMergeChainingConfig(false));
+        assertTrue(resolveUnorderedMergeChainingConfig(true));
+    }
+
+    private boolean resolveUnorderedMergeChainingConfig(boolean unorderedMergeChaining) throws Exception {
+        var props = new TestProperties();
+        if (unorderedMergeChaining) {
+            props.setUnorderedMergeChaining(true);
+        }
+        var cluster = createOneNodeCluster(props);
+        var builder = new StorDistributormanagerConfig.Builder();
+        cluster.getDistributorNodes().getConfig(builder);
+        return (new StorDistributormanagerConfig(builder)).use_unordered_merge_chaining();
+    }
+
+    @Test
     public void testDedicatedClusterControllers() {
         VespaModel noContentModel = createEnd2EndOneNode(new TestProperties().setHostedVespa(true)
                                                                              .setMultitenant(true),
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java b/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java
index 83d139ce461..3630215913e 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/ModelContextImpl.java
@@ -198,6 +198,7 @@ public class ModelContextImpl implements ModelContext {
         private final boolean forwardIssuesAsErrors;
         private final boolean asyncApplyBucketDiff;
         private final boolean ignoreThreadStackSizes;
+        private final boolean unorderedMergeChaining;
 
         public FeatureFlags(FlagSource source, ApplicationId appId) {
             this.defaultTermwiseLimit = flagValue(source, appId, Flags.DEFAULT_TERM_WISE_LIMIT);
@@ -234,6 +235,7 @@ public class ModelContextImpl implements ModelContext {
             this.forwardIssuesAsErrors = flagValue(source, appId, PermanentFlags.FORWARD_ISSUES_AS_ERRORS);
             this.asyncApplyBucketDiff = flagValue(source, appId, Flags.ASYNC_APPLY_BUCKET_DIFF);
             this.ignoreThreadStackSizes = flagValue(source, appId, Flags.IGNORE_THREAD_STACK_SIZES);
+            this.unorderedMergeChaining = flagValue(source, appId, Flags.UNORDERED_MERGE_CHAINING);
         }
 
         @Override public double defaultTermwiseLimit() { return defaultTermwiseLimit; }
@@ -272,6 +274,7 @@ public class ModelContextImpl implements ModelContext {
         @Override public boolean forwardIssuesAsErrors() { return forwardIssuesAsErrors; }
         @Override public boolean asyncApplyBucketDiff() { return asyncApplyBucketDiff; }
         @Override public boolean ignoreThreadStackSizes() { return ignoreThreadStackSizes; }
+        @Override public boolean unorderedMergeChaining() { return unorderedMergeChaining; }
 
         private static <V> V flagValue(FlagSource source, ApplicationId appId, UnboundFlag<? extends V, ?, ?> flag) {
             return flag.bindTo(source)
diff --git a/flags/src/main/java/com/yahoo/vespa/flags/Flags.java b/flags/src/main/java/com/yahoo/vespa/flags/Flags.java
index 8e667ca1957..b7b0c9aea30 100644
--- a/flags/src/main/java/com/yahoo/vespa/flags/Flags.java
+++ b/flags/src/main/java/com/yahoo/vespa/flags/Flags.java
@@ -346,6 +346,13 @@ public class Flags {
             "Takes effect at redeploy",
             ZONE_ID, APPLICATION_ID);
 
+    public static final UnboundBooleanFlag UNORDERED_MERGE_CHAINING = defineFeatureFlag(
+            "unordered-merge-chaining", false,
+            List.of("vekterli", "geirst"), "2021-11-15", "2022-03-01",
+            "Enables the use of unordered merge chains for data merge operations",
+            "Takes effect at redeploy",
+            ZONE_ID, APPLICATION_ID);
+
     public static final UnboundStringFlag JDK_VERSION = defineStringFlag(
             "jdk-version", "11",
             List.of("hmusum"), "2021-10-25", "2021-11-25",