Prepare for exposing more stats about disk and memory indexes, for

metrics and state explorer.

Report serial number for disk and memory indexes.

19 files changed, 177 insertions, 31 deletions

diff --git a/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.cpp b/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.cpp
index f7a16bdcc81..ad78835fa37 100644
--- a/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.cpp
+++ b/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.cpp
@@ -4,29 +4,48 @@
 LOG_SETUP(".proton.index.diskindexwrapper");
 
 #include "diskindexwrapper.h"
+#include <vespa/searchcorespi/index/indexreadutilities.h>
+#include <vespa/searchcorespi/index/indexsearchablevisitor.h>
 
 using search::TuneFileSearch;
+using searchcorespi::index::IndexReadUtilities;
 
 namespace proton {
 
 DiskIndexWrapper::DiskIndexWrapper(const vespalib::string &indexDir,
                                    const TuneFileSearch &tuneFileSearch,
                                    size_t cacheSize)
-    : _index(indexDir, cacheSize)
+    : _index(indexDir, cacheSize),
+      _serialNum(0)
 {
     bool setupIndexOk = _index.setup(tuneFileSearch);
     assert(setupIndexOk);
     (void) setupIndexOk;
+    _serialNum = IndexReadUtilities::readSerialNum(indexDir);
 }
 
 DiskIndexWrapper::DiskIndexWrapper(const DiskIndexWrapper &oldIndex,
                                    const TuneFileSearch &tuneFileSearch,
                                    size_t cacheSize)
-    : _index(oldIndex._index.getIndexDir(), cacheSize)
+    : _index(oldIndex._index.getIndexDir(), cacheSize),
+      _serialNum(0)
 {
     bool setupIndexOk = _index.setup(tuneFileSearch, oldIndex._index);
     assert(setupIndexOk);
     (void) setupIndexOk;
+    _serialNum = oldIndex.getSerialNum();
+}
+
+search::SerialNum
+DiskIndexWrapper::getSerialNum() const
+{
+    return _serialNum;
+}
+
+void
+DiskIndexWrapper::accept(searchcorespi::IndexSearchableVisitor &visitor) const
+{
+    visitor.visit(*this);
 }
 
 }  // namespace proton
diff --git a/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.h b/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.h
index 9deef043f6e..20ba61ea13a 100644
--- a/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.h
+++ b/searchcore/src/vespa/searchcore/proton/index/diskindexwrapper.h
@@ -10,6 +10,7 @@ namespace proton {
 class DiskIndexWrapper : public searchcorespi::index::IDiskIndex {
 private:
     search::diskindex::DiskIndex _index;
+    search::SerialNum _serialNum;
 
 public:
     DiskIndexWrapper(const vespalib::string &indexDir,
@@ -44,6 +45,10 @@ public:
             .sizeOnDisk(_index.getSize());
     }
 
+    virtual search::SerialNum getSerialNum() const override;
+
+    virtual void accept(searchcorespi::IndexSearchableVisitor &visitor) const override;
+
     /**
      * Implements proton::IDiskIndex
      */
diff --git a/searchcore/src/vespa/searchcore/proton/index/indexmanager.cpp b/searchcore/src/vespa/searchcore/proton/index/indexmanager.cpp
index ad2e3f29853..7e9aa2436b1 100644
--- a/searchcore/src/vespa/searchcore/proton/index/indexmanager.cpp
+++ b/searchcore/src/vespa/searchcore/proton/index/indexmanager.cpp
@@ -42,12 +42,14 @@ IndexManager::MaintainerOperations::MaintainerOperations(const FileHeaderContext
 }
 
 IMemoryIndex::SP
-IndexManager::MaintainerOperations::createMemoryIndex(const Schema &schema)
+IndexManager::MaintainerOperations::createMemoryIndex(const Schema &schema,
+                                                      SerialNum serialNum)
 {
     return IMemoryIndex::SP(new MemoryIndexWrapper(schema,
                                                    _fileHeaderContext,
                                                    _tuneFileIndexing,
-                                                   _threadingService));
+                                                   _threadingService,
+                                                   serialNum));
 }
 
 IDiskIndex::SP
diff --git a/searchcore/src/vespa/searchcore/proton/index/indexmanager.h b/searchcore/src/vespa/searchcore/proton/index/indexmanager.h
index 8a7d6a64b30..f81c949d8b3 100644
--- a/searchcore/src/vespa/searchcore/proton/index/indexmanager.h
+++ b/searchcore/src/vespa/searchcore/proton/index/indexmanager.h
@@ -36,7 +36,8 @@ public:
                              threadingService);
 
         virtual searchcorespi::index::IMemoryIndex::SP
-            createMemoryIndex(const search::index::Schema &schema);
+        createMemoryIndex(const search::index::Schema &schema,
+                          SerialNum serialNum) override;
         virtual searchcorespi::index::IDiskIndex::SP
             loadDiskIndex(const vespalib::string &indexDir);
         virtual searchcorespi::index::IDiskIndex::SP
diff --git a/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.cpp b/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.cpp
index c1535082407..73a86c805e2 100644
--- a/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.cpp
+++ b/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.cpp
@@ -7,6 +7,7 @@ LOG_SETUP(".proton.index.memoryindexwrapper");
 #include <vespa/searchlib/common/serialnumfileheadercontext.h>
 #include <vespa/searchlib/diskindex/indexbuilder.h>
 #include <vespa/vespalib/util/exceptions.h>
+#include <vespa/searchcorespi/index/indexsearchablevisitor.h>
 
 using search::TuneFileIndexing;
 using search::common::FileHeaderContext;
@@ -22,9 +23,11 @@ MemoryIndexWrapper::MemoryIndexWrapper(const search::index::Schema &schema,
                                        const search::common::FileHeaderContext &fileHeaderContext,
                                        const TuneFileIndexing &tuneFileIndexing,
                                        searchcorespi::index::IThreadingService &
-                                        threadingService)
+                                       threadingService,
+                                       search::SerialNum serialNum)
     : _index(schema, threadingService.indexFieldInverter(),
              threadingService.indexFieldWriter()),
+      _serialNum(serialNum),
       _fileHeaderContext(fileHeaderContext),
       _tuneFileIndexing(tuneFileIndexing)
 {
@@ -46,5 +49,17 @@ MemoryIndexWrapper::flushToDisk(const vespalib::string &flushDir,
     indexBuilder.close();
 }
 
+search::SerialNum
+MemoryIndexWrapper::getSerialNum() const
+{
+    return _serialNum.load(std::memory_order_relaxed);
+}
+
+void
+MemoryIndexWrapper::accept(searchcorespi::IndexSearchableVisitor &visitor) const
+{
+    visitor.visit(*this);
+}
+
 } // namespace proton
 
diff --git a/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.h b/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.h
index 5a058326db2..a4ef714d09d 100644
--- a/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.h
+++ b/searchcore/src/vespa/searchcore/proton/index/memoryindexwrapper.h
@@ -7,6 +7,7 @@
 #include <vespa/searchcorespi/index/ithreadingservice.h>
 #include <vespa/searchlib/common/tunefileinfo.h>
 #include <vespa/searchlib/common/fileheadercontext.h>
+#include <atomic>
 
 namespace proton {
 
@@ -17,6 +18,7 @@ namespace proton {
 class MemoryIndexWrapper : public searchcorespi::index::IMemoryIndex {
 private:
     search::memoryindex::MemoryIndex _index;
+    std::atomic<search::SerialNum> _serialNum;
     const search::common::FileHeaderContext &_fileHeaderContext;
     const search::TuneFileIndexing _tuneFileIndexing;
 
@@ -25,7 +27,8 @@ public:
                        const search::common::FileHeaderContext &fileHeaderContext,
                        const search::TuneFileIndexing &tuneFileIndexing,
                        searchcorespi::index::IThreadingService &
-                       threadingService);
+                       threadingService,
+                       search::SerialNum serialNum);
 
     /**
      * Implements searchcorespi::IndexSearchable
@@ -53,6 +56,10 @@ public:
             .sizeOnDisk(0);
     }
 
+    virtual search::SerialNum getSerialNum() const override;
+
+    virtual void accept(searchcorespi::IndexSearchableVisitor &visitor) const override;
+
     /**
      * Implements proton::IMemoryIndex
      */
@@ -74,8 +81,10 @@ public:
     uint64_t getStaticMemoryFootprint() const override {
         return _index.getStaticMemoryFootprint();
     }
-    virtual void commit(OnWriteDoneType onWriteDone) override {
+    virtual void commit(OnWriteDoneType onWriteDone,
+                        search::SerialNum serialNum) override {
         _index.commit(onWriteDone);
+        _serialNum.store(serialNum, std::memory_order_relaxed);
     }
     virtual void wipeHistory(const search::index::Schema &schema)  override{
         _index.wipeHistory(schema);
diff --git a/searchcorespi/src/vespa/searchcorespi/index/fakeindexsearchable.h b/searchcorespi/src/vespa/searchcorespi/index/fakeindexsearchable.h
index 0db49c5f2df..00ede178339 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/fakeindexsearchable.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/fakeindexsearchable.h
@@ -37,6 +37,12 @@ public:
     virtual search::SearchableStats getSearchableStats() const {
         return search::SearchableStats();
     }
+
+    virtual search::SerialNum getSerialNum() const override { return 0; }
+    virtual void accept(IndexSearchableVisitor &visitor) const override {
+        (void) visitor;
+    }
+
 };
 
 }  // namespace searchcorespi
diff --git a/searchcorespi/src/vespa/searchcorespi/index/iindexmaintaineroperations.h b/searchcorespi/src/vespa/searchcorespi/index/iindexmaintaineroperations.h
index 2b8a3ac3965..eb5edbf3298 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/iindexmaintaineroperations.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/iindexmaintaineroperations.h
@@ -19,7 +19,7 @@ struct IIndexMaintainerOperations {
     /**
      * Creates a new memory index using the given schema.
      */
-    virtual IMemoryIndex::SP createMemoryIndex(const search::index::Schema &schema) = 0;
+    virtual IMemoryIndex::SP createMemoryIndex(const search::index::Schema &schema, search::SerialNum serialNum) = 0;
 
     /**
      * Loads a disk index from the given directory.
diff --git a/searchcorespi/src/vespa/searchcorespi/index/imemoryindex.h b/searchcorespi/src/vespa/searchcorespi/index/imemoryindex.h
index fabaf730cb7..c8baaf9ca13 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/imemoryindex.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/imemoryindex.h
@@ -61,7 +61,7 @@ struct IMemoryIndex : public searchcorespi::IndexSearchable {
     /**
      * Commits the inserts and removes since the last commit, making them searchable.
      **/
-    virtual void commit(OnWriteDoneType onWriteDone) = 0;
+    virtual void commit(OnWriteDoneType onWriteDone, search::SerialNum serialNum) = 0;
 
     /**
      * Flushes this memory index to disk as a disk index.
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexcollection.cpp b/searchcorespi/src/vespa/searchcorespi/index/indexcollection.cpp
index 0284c4a682e..653cf0a28b4 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexcollection.cpp
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexcollection.cpp
@@ -9,6 +9,7 @@ LOG_SETUP(".searchcorespi.index.indexcollection");
 #include <vespa/searchlib/queryeval/create_blueprint_visitor_helper.h>
 #include <vespa/searchlib/queryeval/intermediate_blueprints.h>
 #include <vespa/searchlib/queryeval/leaf_blueprints.h>
+#include "indexsearchablevisitor.h"
 
 using namespace search::queryeval;
 using namespace search::query;
@@ -116,6 +117,25 @@ IndexCollection::getSearchableStats() const
     return stats;
 }
 
+search::SerialNum
+IndexCollection::getSerialNum() const
+{
+    search::SerialNum serialNum = 0;
+    for (auto &source : _sources) {
+        serialNum = std::max(serialNum, source.source_wrapper->getSerialNum());
+    }
+    return serialNum;
+}
+
+
+void
+IndexCollection::accept(IndexSearchableVisitor &visitor) const
+{
+    for (auto &source : _sources) {
+        source.source_wrapper->accept(visitor);
+    }
+}
+
 namespace {
 
 struct Mixer {
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexcollection.h b/searchcorespi/src/vespa/searchcorespi/index/indexcollection.h
index 223b36fce99..38942abc9dc 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexcollection.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexcollection.h
@@ -61,6 +61,8 @@ public:
                     const Node &term,
                     const IAttributeContext &attrCtx);
     virtual search::SearchableStats getSearchableStats() const;
+    virtual search::SerialNum getSerialNum() const override;
+    virtual void accept(IndexSearchableVisitor &visitor) const override;
 
     static ISearchableIndexCollection::UP replaceAndRenumber(
             const ISourceSelector::SP & selector,
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp
index 36d42e245e1..3db3875b561 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.cpp
@@ -117,6 +117,12 @@ public:
         return _index->createBlueprint(requestContext, fields, term, attrCtx);
     }
     virtual search::SearchableStats getSearchableStats() const { return _index->getSearchableStats(); }
+    virtual search::SerialNum getSerialNum() const override {
+        return _index->getSerialNum();
+    }
+    virtual void accept(IndexSearchableVisitor &visitor) const override {
+        _index->accept(visitor);
+    }
 
     /**
      * Implements IDiskIndex
@@ -293,7 +299,8 @@ IDiskIndex::SP
 IndexMaintainer::flushMemoryIndex(IMemoryIndex &memoryIndex,
                                   uint32_t indexId,
                                   uint32_t docIdLimit,
-                                  SerialNum serialNum)
+                                  SerialNum serialNum,
+                                  FixedSourceSelector::SaveInfo &saveInfo)
 {
     // Called by a flush worker thread
     const string flushDir = getFlushDir(indexId);
@@ -302,6 +309,11 @@ IndexMaintainer::flushMemoryIndex(IMemoryIndex &memoryIndex,
     if (wtSchema.get() != NULL) {
         updateDiskIndexSchema(flushDir, *wtSchema, noSerialNumHigh);
     }
+    IndexWriteUtilities::writeSourceSelector(saveInfo, indexId, getAttrTune(),
+                                             _ctx.getFileHeaderContext(),
+                                             serialNum);
+    IndexWriteUtilities::writeSerialNum(serialNum, flushDir,
+                                        _ctx.getFileHeaderContext());
     return loadDiskIndex(flushDir);
 }
 
@@ -521,14 +533,8 @@ IndexMaintainer::flushMemoryIndex(FlushArgs &args,
     IMemoryIndex &memoryIndex = *args.old_index;
     Schema::SP wtSchema = memoryIndex.getWipeTimeSchema();
     IDiskIndex::SP diskIndex = flushMemoryIndex(memoryIndex, args.old_absolute_id,
-                                                docIdLimit, args.flush_serial_num);
-    IndexWriteUtilities::writeSourceSelector(saveInfo, args.old_absolute_id,
-                                             getAttrTune(), _ctx.getFileHeaderContext(),
-                                             args.flush_serial_num);
-    IndexWriteUtilities::writeSerialNum(args.flush_serial_num,
-                                        getFlushDir(args.old_absolute_id),
-                                        _ctx.getFileHeaderContext());
-
+                                                docIdLimit, args.flush_serial_num,
+                                                saveInfo);
     // Post processing after memory index has been written to disk and
     // opened as disk index.
     args._changeGens = changeGens;
@@ -799,7 +805,7 @@ IndexMaintainer::IndexMaintainer(const IndexMaintainerConfig &config,
       _last_fusion_id(),
       _next_id(),
       _current_index_id(),
-      _current_index(operations.createMemoryIndex(_schema)),
+      _current_index(),
       _current_serial_num(0),
       _flush_serial_num(0),
       _lastFlushTime(),
@@ -848,6 +854,7 @@ IndexMaintainer::IndexMaintainer(const IndexMaintainerConfig &config,
         _selector.reset(getSourceSelector().cloneAndSubtract(ost.str(), id_diff).release());
         assert(_last_fusion_id == _selector->getBaseId());
     }
+    _current_index = operations.createMemoryIndex(_schema, _current_serial_num);
     _current_index_id = getNewAbsoluteId() - _last_fusion_id;
     assert(_current_index_id < ISourceSelector::SOURCE_LIMIT);
     ISearchableIndexCollection::UP sourceList(loadDiskIndexes(spec, ISearchableIndexCollection::UP(new IndexCollection(_selector))));
@@ -874,7 +881,7 @@ IndexMaintainer::initFlush(SerialNum serialNum, searchcorespi::FlushStats * stat
         _current_serial_num = std::max(_current_serial_num, serialNum);
     }
 
-    IMemoryIndex::SP new_index(_operations.createMemoryIndex(getSchema()));
+    IMemoryIndex::SP new_index(_operations.createMemoryIndex(getSchema(), _current_serial_num));
     FlushArgs args;
     args.stats = stats;
     scheduleCommit();
@@ -1132,7 +1139,8 @@ IndexMaintainer::commit()
     // only triggered via scheduleCommit()
     assert(_ctx.getThreadingService().index().isCurrentThread());
     LockGuard lock(_index_update_lock);
-    _current_index->commit(std::shared_ptr<search::IDestructorCallback>());
+    _current_index->commit(std::shared_ptr<search::IDestructorCallback>(),
+                           _current_serial_num);
     // caller calls _ctx.getThreadingService().sync()
 }
 
@@ -1142,7 +1150,7 @@ IndexMaintainer::commit(SerialNum serialNum, OnWriteDoneType onWriteDone)
     assert(_ctx.getThreadingService().index().isCurrentThread());
     LockGuard lock(_index_update_lock);
     _current_serial_num = serialNum;
-    _current_index->commit(onWriteDone);
+    _current_index->commit(onWriteDone, serialNum);
 }
 
 void
@@ -1169,7 +1177,7 @@ void
 IndexMaintainer::setSchema(const Schema & schema, const Schema & fusionSchema)
 {
     assert(_ctx.getThreadingService().master().isCurrentThread());
-    IMemoryIndex::SP new_index(_operations.createMemoryIndex(schema));
+    IMemoryIndex::SP new_index(_operations.createMemoryIndex(schema, _current_serial_num));
     SetSchemaArgs args;
 
     args._newSchema = schema;
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h
index 417f79fa6ca..39e3d116d44 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexmaintainer.h
@@ -185,7 +185,8 @@ class IndexMaintainer : public IIndexManager,
     flushMemoryIndex(IMemoryIndex &memoryIndex,
                      uint32_t indexId,
                      uint32_t docIdLimit,
-                     SerialNum serialNum);
+                     SerialNum serialNum,
+                     search::FixedSourceSelector::SaveInfo &saveInfo);
 
     ISearchableIndexCollection::UP loadDiskIndexes(const FusionSpec &spec, ISearchableIndexCollection::UP sourceList);
     void replaceSource(uint32_t sourceId, const IndexSearchable::SP &source);
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexsearchable.h b/searchcorespi/src/vespa/searchcorespi/index/indexsearchable.h
index 2d4d7cd9674..89a7c8d9f07 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/indexsearchable.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexsearchable.h
@@ -8,9 +8,12 @@
 #include <vespa/searchlib/queryeval/blueprint.h>
 #include <vespa/searchlib/queryeval/irequestcontext.h>
 #include <vespa/searchlib/util/searchable_stats.h>
+#include <vespa/searchlib/common/serialnum.h>
 
 namespace searchcorespi {
 
+class IndexSearchableVisitor;
+
 /**
  * Abstract class extended by components to expose content that can be
  * searched by a query term. A IndexSearchable component supports searching
@@ -72,6 +75,17 @@ public:
      * Returns the searchable stats for this index searchable.
      */
     virtual search::SearchableStats getSearchableStats() const = 0;
+
+    /*
+     * Returns the serial number for this index searchable.
+     */
+    virtual search::SerialNum getSerialNum() const = 0;
+
+    /*
+     * Calls visitor with properly downcasted argument to differentiate
+     * between different types of indexes (disk index or memory index).
+     */
+    virtual void accept(IndexSearchableVisitor &visitor) const = 0;
 };
 
 } // namespace searchcorespi
diff --git a/searchcorespi/src/vespa/searchcorespi/index/indexsearchablevisitor.h b/searchcorespi/src/vespa/searchcorespi/index/indexsearchablevisitor.h
new file mode 100644
index 00000000000..91232ec5c51
--- /dev/null
+++ b/searchcorespi/src/vespa/searchcorespi/index/indexsearchablevisitor.h
@@ -0,0 +1,22 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+namespace searchcorespi {
+
+namespace index {
+
+struct IDiskIndex;
+struct IMemoryIndex;
+
+}
+
+class IndexSearchableVisitor
+{
+public:
+    virtual ~IndexSearchableVisitor() { }
+    virtual void visit(const index::IDiskIndex &index) = 0;
+    virtual void visit(const index::IMemoryIndex &index) = 0;
+};
+
+}  // namespace searchcorespi
diff --git a/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.cpp b/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.cpp
index c993c79a93e..53a2a4d59ea 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.cpp
+++ b/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.cpp
@@ -184,6 +184,22 @@ WarmupIndexCollection::getSearchableStats() const
     return _prev->getSearchableStats();
 }
 
+
+search::SerialNum
+WarmupIndexCollection::getSerialNum() const
+{
+    return std::max(_prev->getSerialNum(), _next->getSerialNum());
+}
+
+
+void
+WarmupIndexCollection::accept(IndexSearchableVisitor &visitor) const
+{
+    _prev->accept(visitor);
+    _next->accept(visitor);
+}
+
+
 void
 WarmupIndexCollection::append(uint32_t id, const IndexSearchable::SP &source)
 {
diff --git a/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.h b/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.h
index a304b3b9df2..be25b81d498 100644
--- a/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.h
+++ b/searchcorespi/src/vespa/searchcorespi/index/warmupindexcollection.h
@@ -49,6 +49,8 @@ public:
                     const Node &term,
                     const IAttributeContext &attrCtx);
     search::SearchableStats getSearchableStats() const override;
+    search::SerialNum getSerialNum() const override;
+    void accept(IndexSearchableVisitor &visitor) const override;
 
     // Implements ISearchableIndexCollection
     void append(uint32_t id, const IndexSearchable::SP &source) override;
diff --git a/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp b/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp
index 8cc12c88463..6d693bb6f42 100644
--- a/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp
+++ b/searchlib/src/vespa/searchlib/diskindex/diskindex.cpp
@@ -47,8 +47,10 @@ DiskIndex::DiskIndex(const vespalib::string &indexDir, size_t cacheSize)
       _bitVectorDicts(),
       _dicts(),
       _tuneFileSearch(),
-      _cache(*this, cacheSize)
+      _cache(*this, cacheSize),
+      _size(0)
 {
+    calculateSize();
 }
 
 bool
@@ -322,11 +324,11 @@ DiskIndex::readBitVector(const LookupResult &lookupRes) const
 }
 
 
-uint64_t
-DiskIndex::getSize() const
+void
+DiskIndex::calculateSize()
 {
     search::DirectoryTraverse dirt(_indexDir.c_str());
-    return dirt.GetTreeSize();
+    _size = dirt.GetTreeSize();
 }
 
 
diff --git a/searchlib/src/vespa/searchlib/diskindex/diskindex.h b/searchlib/src/vespa/searchlib/diskindex/diskindex.h
index 840f4c32738..3a40bb92f8b 100644
--- a/searchlib/src/vespa/searchlib/diskindex/diskindex.h
+++ b/searchlib/src/vespa/searchlib/diskindex/diskindex.h
@@ -78,6 +78,9 @@ private:
     std::vector<std::unique_ptr<index::DictionaryFileRandRead>> _dicts;
     TuneFileSearch			   _tuneFileSearch;
     Cache                                  _cache;
+    uint64_t                               _size;
+
+    void calculateSize();
 
     bool
     loadSchema(void);
@@ -159,8 +162,7 @@ public:
      * Get the size on disk of this index.
      * @return the size of the index.
      */
-    uint64_t
-    getSize() const;
+    uint64_t getSize() const { return _size; }
 
     const index::Schema &
     getSchema(void) const