Move code that updates document db metrics into separate class.

11 files changed, 470 insertions, 360 deletions

diff --git a/searchcore/src/vespa/searchcore/proton/server/CMakeLists.txt b/searchcore/src/vespa/searchcore/proton/server/CMakeLists.txt
index 2df34312b52..d47e87e9e03 100644
--- a/searchcore/src/vespa/searchcore/proton/server/CMakeLists.txt
+++ b/searchcore/src/vespa/searchcore/proton/server/CMakeLists.txt
@@ -28,6 +28,7 @@ vespa_add_library(searchcore_server STATIC
     documentbucketmover.cpp
     documentdb.cpp
     documentdb_commit_job.cpp
+    documentdb_metrics_updater.cpp
     documentdbconfig.cpp
     documentdbconfigscout.cpp
     documentdbconfigmanager.cpp
diff --git a/searchcore/src/vespa/searchcore/proton/server/document_db_explorer.cpp b/searchcore/src/vespa/searchcore/proton/server/document_db_explorer.cpp
index e51e968e550..0c3772cab5b 100644
--- a/searchcore/src/vespa/searchcore/proton/server/document_db_explorer.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/document_db_explorer.cpp
@@ -32,10 +32,7 @@ DocumentDBExplorer::get_state(const Inserter &inserter, bool full) const
         StateReporterUtils::convertToSlime(*_docDb->reportStatus(), ObjectInserter(object, "status"));
     }
     {
-        // TODO(geirst): Avoid const cast by adding const interface to
-        // IDocumentMetaStoreContext as seen from IDocumentSubDB.
-        DocumentMetaStoreReadGuards dmss
-            (const_cast<DocumentSubDBCollection &>(_docDb->getDocumentSubDBs()));
+        DocumentMetaStoreReadGuards dmss(_docDb->getDocumentSubDBs());
         Cursor &documents = object.setObject("documents");
         documents.setLong("active", dmss.numActiveDocs());
         documents.setLong("ready", dmss.numReadyDocs());
diff --git a/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.cpp b/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.cpp
index 2335cd01ec8..952910970ae 100644
--- a/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.cpp
@@ -6,7 +6,7 @@
 
 namespace proton {
 
-DocumentMetaStoreReadGuards::DocumentMetaStoreReadGuards(DocumentSubDBCollection &subDBs)
+DocumentMetaStoreReadGuards::DocumentMetaStoreReadGuards(const DocumentSubDBCollection &subDBs)
     : readydms(subDBs.getReadySubDB()->getDocumentMetaStoreContext().getReadGuard()),
       notreadydms(subDBs.getNotReadySubDB()->getDocumentMetaStoreContext().getReadGuard()),
       remdms(subDBs.getRemSubDB()->getDocumentMetaStoreContext().getReadGuard())
diff --git a/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.h b/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.h
index e58c99ffbec..7baa5576b3b 100644
--- a/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.h
+++ b/searchcore/src/vespa/searchcore/proton/server/document_meta_store_read_guards.h
@@ -18,7 +18,7 @@ struct DocumentMetaStoreReadGuards
     IDocumentMetaStoreContext::IReadGuard::UP notreadydms;
     IDocumentMetaStoreContext::IReadGuard::UP remdms;
 
-    DocumentMetaStoreReadGuards(DocumentSubDBCollection &subDBs);
+    DocumentMetaStoreReadGuards(const DocumentSubDBCollection &subDBs);
     ~DocumentMetaStoreReadGuards();
 
     uint32_t numActiveDocs() const {
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp b/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
index e9e974463b6..94ff5b43a3a 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
@@ -136,8 +136,13 @@ DocumentDB::DocumentDB(const vespalib::string &baseDir,
       _visibility(_feedHandler, _writeService, _feedView),
       _lidSpaceCompactionHandlers(),
       _jobTrackers(),
-      _lastDocStoreCacheStats(),
-      _calc()
+      _calc(),
+      _metricsUpdater(_subDBs,
+                      _writeService,
+                      _jobTrackers,
+                      *_sessionManager,
+                      _writeFilter,
+                      _state)
 {
     assert(configSnapshot);
 
@@ -1010,356 +1015,13 @@ DocumentDB::notifyAllBucketsChanged()
                          _clusterStateHandler, "notready");
 }
 
-namespace {
-
-void
-updateMemoryUsageMetrics(MemoryUsageMetrics &metrics, const MemoryUsage &memoryUsage, MemoryUsage &totalMemoryUsage)
-{
-    metrics.update(memoryUsage);
-    totalMemoryUsage.merge(memoryUsage);
-}
-
-void
-updateIndexMetrics(DocumentDBMetricsCollection &metrics, const search::SearchableStats &stats, MemoryUsage &totalMemoryUsage)
-{
-    DocumentDBTaggedMetrics::IndexMetrics &indexMetrics = metrics.getTaggedMetrics().index;
-    indexMetrics.diskUsage.set(stats.sizeOnDisk());
-    updateMemoryUsageMetrics(indexMetrics.memoryUsage, stats.memoryUsage(), totalMemoryUsage);
-    indexMetrics.docsInMemory.set(stats.docsInMemory());
-
-    LegacyDocumentDBMetrics::IndexMetrics &legacyIndexMetrics = metrics.getLegacyMetrics().index;
-    legacyIndexMetrics.memoryUsage.set(stats.memoryUsage().allocatedBytes());
-    legacyIndexMetrics.docsInMemory.set(stats.docsInMemory());
-    legacyIndexMetrics.diskUsage.set(stats.sizeOnDisk());
-}
-
-struct TempAttributeMetric
-{
-    MemoryUsage _memoryUsage;
-    uint64_t    _bitVectors;
-
-    TempAttributeMetric()
-        : _memoryUsage(),
-          _bitVectors(0)
-    {}
-};
-
-struct TempAttributeMetrics
-{
-    typedef std::map<vespalib::string, TempAttributeMetric> AttrMap;
-    TempAttributeMetric _total;
-    AttrMap _attrs;
-};
-
-bool
-isReadySubDB(const IDocumentSubDB *subDb, const DocumentSubDBCollection &subDbs)
-{
-    return subDb == subDbs.getReadySubDB();
-}
-
-bool
-isNotReadySubDB(const IDocumentSubDB *subDb, const DocumentSubDBCollection &subDbs)
-{
-    return subDb == subDbs.getNotReadySubDB();
-}
-
-void
-fillTempAttributeMetrics(TempAttributeMetrics &metrics, const vespalib::string &attrName,
-                         const MemoryUsage &memoryUsage, uint32_t bitVectors)
-{
-    metrics._total._memoryUsage.merge(memoryUsage);
-    metrics._total._bitVectors += bitVectors;
-    TempAttributeMetric &m = metrics._attrs[attrName];
-    m._memoryUsage.merge(memoryUsage);
-    m._bitVectors += bitVectors;
-}
-
-void
-fillTempAttributeMetrics(TempAttributeMetrics &totalMetrics,
-                         TempAttributeMetrics &readyMetrics,
-                         TempAttributeMetrics &notReadyMetrics,
-                         const DocumentSubDBCollection &subDbs)
-{
-    for (const auto subDb : subDbs) {
-        proton::IAttributeManager::SP attrMgr(subDb->getAttributeManager());
-        if (attrMgr) {
-            TempAttributeMetrics *subMetrics =
-                    (isReadySubDB(subDb, subDbs) ? &readyMetrics :
-                     (isNotReadySubDB(subDb, subDbs) ? &notReadyMetrics : nullptr));
-            std::vector<search::AttributeGuard> list;
-            attrMgr->getAttributeListAll(list);
-            for (const auto &attr : list) {
-                const search::attribute::Status &status = attr->getStatus();
-                MemoryUsage memoryUsage(status.getAllocated(), status.getUsed(), status.getDead(), status.getOnHold());
-                uint32_t bitVectors = status.getBitVectors();
-                fillTempAttributeMetrics(totalMetrics, attr->getName(), memoryUsage, bitVectors);
-                if (subMetrics != nullptr) {
-                    fillTempAttributeMetrics(*subMetrics, attr->getName(), memoryUsage, bitVectors);
-                }
-            }
-        }
-    }
-}
-
-void
-updateLegacyAttributeMetrics(LegacyAttributeMetrics &metrics, const TempAttributeMetrics &tmpMetrics)
-{
-    for (const auto &attr : tmpMetrics._attrs) {
-        LegacyAttributeMetrics::List::Entry *entry = metrics.list.get(attr.first);
-        if (entry) {
-            entry->memoryUsage.set(attr.second._memoryUsage.allocatedBytes());
-            entry->bitVectors.set(attr.second._bitVectors);
-        } else {
-            LOG(debug, "Could not update metrics for attribute: '%s'", attr.first.c_str());
-        }
-    }
-    metrics.memoryUsage.set(tmpMetrics._total._memoryUsage.allocatedBytes());
-    metrics.bitVectors.set(tmpMetrics._total._bitVectors);
-}
-
-void
-updateAttributeMetrics(AttributeMetrics &metrics, const TempAttributeMetrics &tmpMetrics)
-{
-    for (const auto &attr : tmpMetrics._attrs) {
-        auto entry = metrics.get(attr.first);
-        if (entry) {
-            entry->memoryUsage.update(attr.second._memoryUsage);
-        }
-    }
-}
-
-void
-updateAttributeMetrics(DocumentDBMetricsCollection &metrics, const DocumentSubDBCollection &subDbs, MemoryUsage &totalMemoryUsage)
-{
-    TempAttributeMetrics totalMetrics;
-    TempAttributeMetrics readyMetrics;
-    TempAttributeMetrics notReadyMetrics;
-    fillTempAttributeMetrics(totalMetrics, readyMetrics, notReadyMetrics, subDbs);
-
-    updateLegacyAttributeMetrics(metrics.getLegacyMetrics().attributes, totalMetrics);
-    updateLegacyAttributeMetrics(metrics.getLegacyMetrics().ready.attributes, readyMetrics);
-    updateLegacyAttributeMetrics(metrics.getLegacyMetrics().notReady.attributes, notReadyMetrics);
-
-    updateAttributeMetrics(metrics.getTaggedMetrics().ready.attributes, readyMetrics);
-    updateAttributeMetrics(metrics.getTaggedMetrics().notReady.attributes, notReadyMetrics);
-    updateMemoryUsageMetrics(metrics.getTaggedMetrics().attribute.totalMemoryUsage, totalMetrics._total._memoryUsage, totalMemoryUsage);
-}
-
-namespace {
-
-void
-updateLegacyRankProfileMetrics(LegacyDocumentDBMetrics::MatchingMetrics &matchingMetrics,
-                               const vespalib::string &rankProfileName,
-                               const MatchingStats &stats)
-{
-    auto itr = matchingMetrics.rank_profiles.find(rankProfileName);
-    assert(itr != matchingMetrics.rank_profiles.end());
-    itr->second->update(stats);
-}
-
-}
-
-void
-updateMatchingMetrics(DocumentDBMetricsCollection &metrics, const IDocumentSubDB &ready)
-{
-    MatchingStats totalStats;
-    for (const auto &rankProfile : metrics.getTaggedMetrics().matching.rank_profiles) {
-        MatchingStats matchingStats = ready.getMatcherStats(rankProfile.first);
-        rankProfile.second->update(matchingStats);
-        updateLegacyRankProfileMetrics(metrics.getLegacyMetrics().matching, rankProfile.first, matchingStats);
-
-        totalStats.add(matchingStats);
-    }
-    metrics.getTaggedMetrics().matching.update(totalStats);
-    metrics.getLegacyMetrics().matching.update(totalStats);
-}
-
-void
-updateSessionCacheMetrics(DocumentDBMetricsCollection &metrics, proton::matching::SessionManager &sessionManager)
-{
-    auto searchStats = sessionManager.getSearchStats();
-    metrics.getTaggedMetrics().sessionCache.search.update(searchStats);
-
-    auto groupingStats = sessionManager.getGroupingStats();
-    metrics.getTaggedMetrics().sessionCache.grouping.update(groupingStats);
-    metrics.getLegacyMetrics().sessionManager.update(groupingStats);
-}
-
-void
-updateDocumentsMetrics(DocumentDBMetricsCollection &metrics, DocumentSubDBCollection &subDbs)
-{
-    DocumentMetaStoreReadGuards dms(subDbs);
-    uint32_t active = dms.numActiveDocs();
-    uint32_t ready = dms.numReadyDocs();
-    uint32_t total = dms.numTotalDocs();
-    uint32_t removed = dms.numRemovedDocs();
-
-    auto &docsMetrics = metrics.getTaggedMetrics().documents;
-    docsMetrics.active.set(active);
-    docsMetrics.ready.set(ready);
-    docsMetrics.total.set(total);
-    docsMetrics.removed.set(removed);
-
-    auto &legacyMetrics = metrics.getLegacyMetrics();
-    legacyMetrics.numActiveDocs.set(active);
-    legacyMetrics.numIndexedDocs.set(ready);
-    legacyMetrics.numStoredDocs.set(total);
-    legacyMetrics.numRemovedDocs.set(removed);
-}
-
-void
-updateDocumentStoreCacheHitRate(const CacheStats &current, const CacheStats &last,
-                                metrics::LongAverageMetric &cacheHitRate)
-{
-    if (current.lookups() < last.lookups() || current.hits < last.hits) {
-        LOG(warning, "Not adding document store cache hit rate metrics as values calculated "
-                "are corrupt. current.lookups=%" PRIu64 ", last.lookups=%" PRIu64 ", current.hits=%" PRIu64 ", last.hits=%" PRIu64 ".",
-            current.lookups(), last.lookups(), current.hits, last.hits);
-    } else {
-        if ((current.lookups() - last.lookups()) > 0xffffffffull
-            || (current.hits - last.hits) > 0xffffffffull)
-        {
-            LOG(warning, "Document store cache hit rate metrics to add are suspiciously high."
-                    " lookups diff=%" PRIu64 ", hits diff=%" PRIu64 ".",
-                current.lookups() - last.lookups(), current.hits - last.hits);
-        }
-        cacheHitRate.addTotalValueWithCount(current.hits - last.hits, current.lookups() - last.lookups());
-    }
-}
-
-void
-updateCountMetric(uint64_t currVal, uint64_t lastVal, metrics::LongCountMetric &metric)
-{
-    uint64_t delta = (currVal >= lastVal) ? (currVal - lastVal) : 0;
-    metric.inc(delta);
-}
-
-void
-updateDocstoreMetrics(LegacyDocumentDBMetrics::DocstoreMetrics &metrics,
-                      const DocumentSubDBCollection &sub_dbs,
-                      CacheStats &lastCacheStats)
-{
-    size_t memoryUsage = 0;
-    CacheStats cache_stats;
-    for (const auto subDb : sub_dbs) {
-        const ISummaryManager::SP &summaryMgr = subDb->getSummaryManager();
-        if (summaryMgr) {
-            cache_stats += summaryMgr->getBackingStore().getCacheStats();
-            memoryUsage += summaryMgr->getBackingStore().memoryUsed();
-        }
-    }
-    metrics.memoryUsage.set(memoryUsage);
-    updateCountMetric(cache_stats.lookups(), lastCacheStats.lookups(), metrics.cacheLookups);
-    updateDocumentStoreCacheHitRate(cache_stats, lastCacheStats, metrics.cacheHitRate);
-    metrics.cacheElements.set(cache_stats.elements);
-    metrics.cacheMemoryUsed.set(cache_stats.memory_used);
-    lastCacheStats = cache_stats;
-}
-
-void
-updateDocumentStoreMetrics(DocumentDBTaggedMetrics::SubDBMetrics::DocumentStoreMetrics &metrics,
-                           IDocumentSubDB *subDb,
-                           CacheStats &lastCacheStats,
-                           MemoryUsage &totalMemoryUsage)
-{
-    const ISummaryManager::SP &summaryMgr = subDb->getSummaryManager();
-    search::IDocumentStore &backingStore = summaryMgr->getBackingStore();
-    search::DataStoreStorageStats storageStats(backingStore.getStorageStats());
-    metrics.diskUsage.set(storageStats.diskUsage());
-    metrics.diskBloat.set(storageStats.diskBloat());
-    metrics.maxBucketSpread.set(storageStats.maxBucketSpread());
-    updateMemoryUsageMetrics(metrics.memoryUsage, backingStore.getMemoryUsage(), totalMemoryUsage);
-
-    search::CacheStats cacheStats = backingStore.getCacheStats();
-    totalMemoryUsage.incAllocatedBytes(cacheStats.memory_used);
-    metrics.cache.memoryUsage.set(cacheStats.memory_used);
-    metrics.cache.elements.set(cacheStats.elements);
-    updateDocumentStoreCacheHitRate(cacheStats, lastCacheStats, metrics.cache.hitRate);
-    updateCountMetric(cacheStats.lookups(), lastCacheStats.lookups(), metrics.cache.lookups);
-    updateCountMetric(cacheStats.invalidations, lastCacheStats.invalidations, metrics.cache.invalidations);
-    lastCacheStats = cacheStats;
-}
-
-template <typename MetricSetType>
-void
-updateLidSpaceMetrics(MetricSetType &metrics, const search::IDocumentMetaStore &metaStore)
-{
-    LidUsageStats stats = metaStore.getLidUsageStats();
-    metrics.lidLimit.set(stats.getLidLimit());
-    metrics.usedLids.set(stats.getUsedLids());
-    metrics.lowestFreeLid.set(stats.getLowestFreeLid());
-    metrics.highestUsedLid.set(stats.getHighestUsedLid());
-    metrics.lidBloatFactor.set(stats.getLidBloatFactor());
-    metrics.lidFragmentationFactor.set(stats.getLidFragmentationFactor());
-}
-
-}  // namespace
-
 void
 DocumentDB::updateMetrics(DocumentDBMetricsCollection &metrics)
 {
     if (_state.getState() < DDBState::State::REPLAY_TRANSACTION_LOG) {
         return;
     }
-
-    MemoryUsage totalMemoryUsage;
-    ExecutorThreadingServiceStats threadingServiceStats = _writeService.getStats();
-    updateLegacyMetrics(metrics.getLegacyMetrics(), threadingServiceStats);
-    updateIndexMetrics(metrics, _subDBs.getReadySubDB()->getSearchableStats(), totalMemoryUsage);
-    updateAttributeMetrics(metrics, _subDBs, totalMemoryUsage);
-    updateMatchingMetrics(metrics, *_subDBs.getReadySubDB());
-    updateSessionCacheMetrics(metrics, *_sessionManager);
-    updateDocumentsMetrics(metrics, _subDBs);
-    updateMiscMetrics(metrics.getTaggedMetrics(), threadingServiceStats, totalMemoryUsage);
-    metrics.getTaggedMetrics().totalMemoryUsage.update(totalMemoryUsage);
-}
-
-void
-DocumentDB::updateLegacyMetrics(LegacyDocumentDBMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats)
-{
-    metrics.executor.update(threadingServiceStats.getMasterExecutorStats());
-    metrics.summaryExecutor.update(threadingServiceStats.getSummaryExecutorStats());
-    metrics.indexExecutor.update(threadingServiceStats.getIndexExecutorStats());
-    updateDocstoreMetrics(metrics.docstore, _subDBs, _lastDocStoreCacheStats.total);
-    metrics.numDocs.set(getNumDocs());
-
-    DocumentMetaStoreReadGuards dmss(_subDBs);
-    updateLidSpaceMetrics(metrics.ready.docMetaStore, dmss.readydms->get());
-    updateLidSpaceMetrics(metrics.notReady.docMetaStore, dmss.notreadydms->get());
-    updateLidSpaceMetrics(metrics.removed.docMetaStore, dmss.remdms->get());
-
-    metrics.numBadConfigs.set(_state.getDelayedConfig() ? 1u : 0u);
-}
-
-void
-DocumentDB::
-updateAttributeResourceUsageMetrics(DocumentDBTaggedMetrics::AttributeMetrics &metrics)
-{
-    AttributeUsageFilter &writeFilter(_writeFilter);
-    AttributeUsageStats attributeUsageStats = writeFilter.getAttributeUsageStats();
-    bool feedBlocked = !writeFilter.acceptWriteOperation();
-    double enumStoreUsed = attributeUsageStats.enumStoreUsage().getUsage().usage();
-    double multiValueUsed = attributeUsageStats.multiValueUsage().getUsage().usage();
-    metrics.resourceUsage.enumStore.set(enumStoreUsed);
-    metrics.resourceUsage.multiValue.set(multiValueUsed);
-    metrics.resourceUsage.feedingBlocked.set(feedBlocked ? 1 : 0);
-}
-
-void
-DocumentDB::updateMiscMetrics(DocumentDBTaggedMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats, MemoryUsage &totalMemoryUsage)
-{
-    metrics.threadingService.update(threadingServiceStats);
-    _jobTrackers.updateMetrics(metrics.job);
-
-    updateAttributeResourceUsageMetrics(metrics.attribute);
-    updateDocumentStoreMetrics(metrics.ready.documentStore, _subDBs.getReadySubDB(), _lastDocStoreCacheStats.readySubDb, totalMemoryUsage);
-    updateDocumentStoreMetrics(metrics.removed.documentStore, _subDBs.getRemSubDB(), _lastDocStoreCacheStats.removedSubDb, totalMemoryUsage);
-    updateDocumentStoreMetrics(metrics.notReady.documentStore, _subDBs.getNotReadySubDB(), _lastDocStoreCacheStats.notReadySubDb, totalMemoryUsage);
-
-    DocumentMetaStoreReadGuards dmss(_subDBs);
-    updateLidSpaceMetrics(metrics.ready.lidSpace, dmss.readydms->get());
-    updateLidSpaceMetrics(metrics.notReady.lidSpace, dmss.notreadydms->get());
-    updateLidSpaceMetrics(metrics.removed.lidSpace, dmss.remdms->get());
+    _metricsUpdater.updateMetrics(metrics);
 }
 
 void
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb.h b/searchcore/src/vespa/searchcore/proton/server/documentdb.h
index 66dc47e78c0..fb23b113f3b 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentdb.h
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb.h
@@ -6,11 +6,12 @@
 #include "configstore.h"
 #include "ddbstate.h"
 #include "disk_mem_usage_forwarder.h"
+#include "documentdb_metrics_updater.h"
+#include "document_db_config_owner.h"
 #include "documentdbconfig.h"
 #include "documentsubdbcollection.h"
 #include "executorthreadingservice.h"
 #include "feedhandler.h"
-#include "document_db_config_owner.h"
 #include "i_document_subdb_owner.h"
 #include "i_feed_handler_owner.h"
 #include "i_lid_space_compaction_handler.h"
@@ -135,10 +136,8 @@ private:
     VisibilityHandler             _visibility;
     ILidSpaceCompactionHandler::Vector _lidSpaceCompactionHandlers;
     DocumentDBJobTrackers         _jobTrackers;
-
-    // Last updated document store cache statistics. Necessary due to metrics implementation is upside down.
-    DocumentStoreCacheStats       _lastDocStoreCacheStats;
     IBucketStateCalculator::SP    _calc;
+    DocumentDBMetricsUpdater      _metricsUpdater;
 
     void registerReference();
     void setActiveConfig(const DocumentDBConfig::SP &config, SerialNum serialNum, int64_t generation);
@@ -206,10 +205,6 @@ private:
     virtual void notifyClusterStateChanged(const IBucketStateCalculator::SP &newCalc) override;
     void notifyAllBucketsChanged();
 
-    void updateLegacyMetrics(LegacyDocumentDBMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats);
-    void updateMiscMetrics(DocumentDBTaggedMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats, search::MemoryUsage &totalMemoryUsage);
-    void updateAttributeResourceUsageMetrics(DocumentDBTaggedMetrics::AttributeMetrics &metrics);
-
     /*
      * Tear down references to this document db (e.g. listeners for
      * gid to lid changes) from other document dbs.
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb_metrics_updater.cpp b/searchcore/src/vespa/searchcore/proton/server/documentdb_metrics_updater.cpp
new file mode 100644
index 00000000000..684775172aa
--- /dev/null
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb_metrics_updater.cpp
@@ -0,0 +1,393 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "ddbstate.h"
+#include "document_meta_store_read_guards.h"
+#include "documentdb_metrics_updater.h"
+#include "documentsubdbcollection.h"
+#include "executorthreadingservice.h"
+#include "idocumentsubdb.h"
+#include <vespa/searchcommon/attribute/status.h>
+#include <vespa/searchcore/proton/attribute/attribute_usage_filter.h>
+#include <vespa/searchcore/proton/attribute/i_attribute_manager.h>
+#include <vespa/searchcore/proton/docsummary/isummarymanager.h>
+#include <vespa/searchcore/proton/matching/matching_stats.h>
+#include <vespa/searchcore/proton/matching/matching_stats.h>
+#include <vespa/searchcore/proton/metrics/documentdb_job_trackers.h>
+#include <vespa/searchcore/proton/metrics/documentdb_metrics_collection.h>
+#include <vespa/searchcore/proton/metrics/executor_threading_service_stats.h>
+#include <vespa/searchlib/attribute/attributevector.h>
+#include <vespa/searchlib/docstore/cachestats.h>
+#include <vespa/searchlib/util/memoryusage.h>
+#include <vespa/searchlib/util/searchable_stats.h>
+
+#include <vespa/log/log.h>
+LOG_SETUP(".proton.server.documentdb_metrics_updater");
+
+using search::LidUsageStats;
+using search::CacheStats;
+using search::MemoryUsage;
+
+namespace proton {
+
+using matching::MatchingStats;
+
+DocumentDBMetricsUpdater::DocumentDBMetricsUpdater(const DocumentSubDBCollection &subDBs,
+                                                   ExecutorThreadingService &writeService,
+                                                   DocumentDBJobTrackers &jobTrackers,
+                                                   matching::SessionManager &sessionManager,
+                                                   const AttributeUsageFilter &writeFilter,
+                                                   const DDBState &state)
+    : _subDBs(subDBs),
+      _writeService(writeService),
+      _jobTrackers(jobTrackers),
+      _sessionManager(sessionManager),
+      _writeFilter(writeFilter),
+      _state(state)
+{
+}
+
+DocumentDBMetricsUpdater::~DocumentDBMetricsUpdater() = default;
+
+namespace {
+
+void
+updateMemoryUsageMetrics(MemoryUsageMetrics &metrics, const MemoryUsage &memoryUsage, MemoryUsage &totalMemoryUsage)
+{
+    metrics.update(memoryUsage);
+    totalMemoryUsage.merge(memoryUsage);
+}
+
+void
+updateIndexMetrics(DocumentDBMetricsCollection &metrics, const search::SearchableStats &stats, MemoryUsage &totalMemoryUsage)
+{
+    DocumentDBTaggedMetrics::IndexMetrics &indexMetrics = metrics.getTaggedMetrics().index;
+    indexMetrics.diskUsage.set(stats.sizeOnDisk());
+    updateMemoryUsageMetrics(indexMetrics.memoryUsage, stats.memoryUsage(), totalMemoryUsage);
+    indexMetrics.docsInMemory.set(stats.docsInMemory());
+
+    LegacyDocumentDBMetrics::IndexMetrics &legacyIndexMetrics = metrics.getLegacyMetrics().index;
+    legacyIndexMetrics.memoryUsage.set(stats.memoryUsage().allocatedBytes());
+    legacyIndexMetrics.docsInMemory.set(stats.docsInMemory());
+    legacyIndexMetrics.diskUsage.set(stats.sizeOnDisk());
+}
+
+struct TempAttributeMetric
+{
+    MemoryUsage memoryUsage;
+    uint64_t    bitVectors;
+
+    TempAttributeMetric()
+        : memoryUsage(),
+          bitVectors(0)
+    {}
+};
+
+struct TempAttributeMetrics
+{
+    typedef std::map<vespalib::string, TempAttributeMetric> AttrMap;
+    TempAttributeMetric total;
+    AttrMap attrs;
+};
+
+bool
+isReadySubDB(const IDocumentSubDB *subDb, const DocumentSubDBCollection &subDbs)
+{
+    return subDb == subDbs.getReadySubDB();
+}
+
+bool
+isNotReadySubDB(const IDocumentSubDB *subDb, const DocumentSubDBCollection &subDbs)
+{
+    return subDb == subDbs.getNotReadySubDB();
+}
+
+void
+fillTempAttributeMetrics(TempAttributeMetrics &metrics, const vespalib::string &attrName,
+                         const MemoryUsage &memoryUsage, uint32_t bitVectors)
+{
+    metrics.total.memoryUsage.merge(memoryUsage);
+    metrics.total.bitVectors += bitVectors;
+    TempAttributeMetric &m = metrics.attrs[attrName];
+    m.memoryUsage.merge(memoryUsage);
+    m.bitVectors += bitVectors;
+}
+
+void
+fillTempAttributeMetrics(TempAttributeMetrics &totalMetrics,
+                         TempAttributeMetrics &readyMetrics,
+                         TempAttributeMetrics &notReadyMetrics,
+                         const DocumentSubDBCollection &subDbs)
+{
+    for (const auto subDb : subDbs) {
+        proton::IAttributeManager::SP attrMgr(subDb->getAttributeManager());
+        if (attrMgr) {
+            TempAttributeMetrics *subMetrics =
+                    (isReadySubDB(subDb, subDbs) ? &readyMetrics :
+                     (isNotReadySubDB(subDb, subDbs) ? &notReadyMetrics : nullptr));
+            std::vector<search::AttributeGuard> list;
+            attrMgr->getAttributeListAll(list);
+            for (const auto &attr : list) {
+                const search::attribute::Status &status = attr->getStatus();
+                MemoryUsage memoryUsage(status.getAllocated(), status.getUsed(), status.getDead(), status.getOnHold());
+                uint32_t bitVectors = status.getBitVectors();
+                fillTempAttributeMetrics(totalMetrics, attr->getName(), memoryUsage, bitVectors);
+                if (subMetrics != nullptr) {
+                    fillTempAttributeMetrics(*subMetrics, attr->getName(), memoryUsage, bitVectors);
+                }
+            }
+        }
+    }
+}
+
+void
+updateLegacyAttributeMetrics(LegacyAttributeMetrics &metrics, const TempAttributeMetrics &tmpMetrics)
+{
+    for (const auto &attr : tmpMetrics.attrs) {
+        LegacyAttributeMetrics::List::Entry *entry = metrics.list.get(attr.first);
+        if (entry) {
+            entry->memoryUsage.set(attr.second.memoryUsage.allocatedBytes());
+            entry->bitVectors.set(attr.second.bitVectors);
+        } else {
+            LOG(debug, "Could not update metrics for attribute: '%s'", attr.first.c_str());
+        }
+    }
+    metrics.memoryUsage.set(tmpMetrics.total.memoryUsage.allocatedBytes());
+    metrics.bitVectors.set(tmpMetrics.total.bitVectors);
+}
+
+void
+updateAttributeMetrics(AttributeMetrics &metrics, const TempAttributeMetrics &tmpMetrics)
+{
+    for (const auto &attr : tmpMetrics.attrs) {
+        auto entry = metrics.get(attr.first);
+        if (entry) {
+            entry->memoryUsage.update(attr.second.memoryUsage);
+        }
+    }
+}
+
+void
+updateAttributeMetrics(DocumentDBMetricsCollection &metrics, const DocumentSubDBCollection &subDbs, MemoryUsage &totalMemoryUsage)
+{
+    TempAttributeMetrics totalMetrics;
+    TempAttributeMetrics readyMetrics;
+    TempAttributeMetrics notReadyMetrics;
+    fillTempAttributeMetrics(totalMetrics, readyMetrics, notReadyMetrics, subDbs);
+
+    updateLegacyAttributeMetrics(metrics.getLegacyMetrics().attributes, totalMetrics);
+    updateLegacyAttributeMetrics(metrics.getLegacyMetrics().ready.attributes, readyMetrics);
+    updateLegacyAttributeMetrics(metrics.getLegacyMetrics().notReady.attributes, notReadyMetrics);
+
+    updateAttributeMetrics(metrics.getTaggedMetrics().ready.attributes, readyMetrics);
+    updateAttributeMetrics(metrics.getTaggedMetrics().notReady.attributes, notReadyMetrics);
+    updateMemoryUsageMetrics(metrics.getTaggedMetrics().attribute.totalMemoryUsage, totalMetrics.total.memoryUsage, totalMemoryUsage);
+}
+
+void
+updateLegacyRankProfileMetrics(LegacyDocumentDBMetrics::MatchingMetrics &matchingMetrics,
+                               const vespalib::string &rankProfileName,
+                               const MatchingStats &stats)
+{
+    auto itr = matchingMetrics.rank_profiles.find(rankProfileName);
+    assert(itr != matchingMetrics.rank_profiles.end());
+    itr->second->update(stats);
+}
+
+void
+updateMatchingMetrics(DocumentDBMetricsCollection &metrics, const IDocumentSubDB &ready)
+{
+    MatchingStats totalStats;
+    for (const auto &rankProfile : metrics.getTaggedMetrics().matching.rank_profiles) {
+        MatchingStats matchingStats = ready.getMatcherStats(rankProfile.first);
+        rankProfile.second->update(matchingStats);
+        updateLegacyRankProfileMetrics(metrics.getLegacyMetrics().matching, rankProfile.first, matchingStats);
+
+        totalStats.add(matchingStats);
+    }
+    metrics.getTaggedMetrics().matching.update(totalStats);
+    metrics.getLegacyMetrics().matching.update(totalStats);
+}
+
+void
+updateSessionCacheMetrics(DocumentDBMetricsCollection &metrics, proton::matching::SessionManager &sessionManager)
+{
+    auto searchStats = sessionManager.getSearchStats();
+    metrics.getTaggedMetrics().sessionCache.search.update(searchStats);
+
+    auto groupingStats = sessionManager.getGroupingStats();
+    metrics.getTaggedMetrics().sessionCache.grouping.update(groupingStats);
+    metrics.getLegacyMetrics().sessionManager.update(groupingStats);
+}
+
+void
+updateDocumentsMetrics(DocumentDBMetricsCollection &metrics, const DocumentSubDBCollection &subDbs)
+{
+    DocumentMetaStoreReadGuards dms(subDbs);
+    uint32_t active = dms.numActiveDocs();
+    uint32_t ready = dms.numReadyDocs();
+    uint32_t total = dms.numTotalDocs();
+    uint32_t removed = dms.numRemovedDocs();
+
+    auto &docsMetrics = metrics.getTaggedMetrics().documents;
+    docsMetrics.active.set(active);
+    docsMetrics.ready.set(ready);
+    docsMetrics.total.set(total);
+    docsMetrics.removed.set(removed);
+
+    auto &legacyMetrics = metrics.getLegacyMetrics();
+    legacyMetrics.numDocs.set(ready);
+    legacyMetrics.numActiveDocs.set(active);
+    legacyMetrics.numIndexedDocs.set(ready);
+    legacyMetrics.numStoredDocs.set(total);
+    legacyMetrics.numRemovedDocs.set(removed);
+}
+
+void
+updateDocumentStoreCacheHitRate(const CacheStats &current, const CacheStats &last,
+                                metrics::LongAverageMetric &cacheHitRate)
+{
+    if (current.lookups() < last.lookups() || current.hits < last.hits) {
+        LOG(warning, "Not adding document store cache hit rate metrics as values calculated "
+                     "are corrupt. current.lookups=%" PRIu64 ", last.lookups=%" PRIu64 ", current.hits=%" PRIu64 ", last.hits=%" PRIu64 ".",
+            current.lookups(), last.lookups(), current.hits, last.hits);
+    } else {
+        if ((current.lookups() - last.lookups()) > 0xffffffffull
+            || (current.hits - last.hits) > 0xffffffffull)
+        {
+            LOG(warning, "Document store cache hit rate metrics to add are suspiciously high."
+                         " lookups diff=%" PRIu64 ", hits diff=%" PRIu64 ".",
+                current.lookups() - last.lookups(), current.hits - last.hits);
+        }
+        cacheHitRate.addTotalValueWithCount(current.hits - last.hits, current.lookups() - last.lookups());
+    }
+}
+
+void
+updateCountMetric(uint64_t currVal, uint64_t lastVal, metrics::LongCountMetric &metric)
+{
+    uint64_t delta = (currVal >= lastVal) ? (currVal - lastVal) : 0;
+    metric.inc(delta);
+}
+
+void
+updateDocstoreMetrics(LegacyDocumentDBMetrics::DocstoreMetrics &metrics,
+                      const DocumentSubDBCollection &sub_dbs,
+                      CacheStats &lastCacheStats)
+{
+    size_t memoryUsage = 0;
+    CacheStats cache_stats;
+    for (const auto subDb : sub_dbs) {
+        const ISummaryManager::SP &summaryMgr = subDb->getSummaryManager();
+        if (summaryMgr) {
+            cache_stats += summaryMgr->getBackingStore().getCacheStats();
+            memoryUsage += summaryMgr->getBackingStore().memoryUsed();
+        }
+    }
+    metrics.memoryUsage.set(memoryUsage);
+    updateCountMetric(cache_stats.lookups(), lastCacheStats.lookups(), metrics.cacheLookups);
+    updateDocumentStoreCacheHitRate(cache_stats, lastCacheStats, metrics.cacheHitRate);
+    metrics.cacheElements.set(cache_stats.elements);
+    metrics.cacheMemoryUsed.set(cache_stats.memory_used);
+    lastCacheStats = cache_stats;
+}
+
+void
+updateDocumentStoreMetrics(DocumentDBTaggedMetrics::SubDBMetrics::DocumentStoreMetrics &metrics,
+                           const IDocumentSubDB *subDb,
+                           CacheStats &lastCacheStats,
+                           MemoryUsage &totalMemoryUsage)
+{
+    const ISummaryManager::SP &summaryMgr = subDb->getSummaryManager();
+    search::IDocumentStore &backingStore = summaryMgr->getBackingStore();
+    search::DataStoreStorageStats storageStats(backingStore.getStorageStats());
+    metrics.diskUsage.set(storageStats.diskUsage());
+    metrics.diskBloat.set(storageStats.diskBloat());
+    metrics.maxBucketSpread.set(storageStats.maxBucketSpread());
+    updateMemoryUsageMetrics(metrics.memoryUsage, backingStore.getMemoryUsage(), totalMemoryUsage);
+
+    search::CacheStats cacheStats = backingStore.getCacheStats();
+    totalMemoryUsage.incAllocatedBytes(cacheStats.memory_used);
+    metrics.cache.memoryUsage.set(cacheStats.memory_used);
+    metrics.cache.elements.set(cacheStats.elements);
+    updateDocumentStoreCacheHitRate(cacheStats, lastCacheStats, metrics.cache.hitRate);
+    updateCountMetric(cacheStats.lookups(), lastCacheStats.lookups(), metrics.cache.lookups);
+    updateCountMetric(cacheStats.invalidations, lastCacheStats.invalidations, metrics.cache.invalidations);
+    lastCacheStats = cacheStats;
+}
+
+template <typename MetricSetType>
+void
+updateLidSpaceMetrics(MetricSetType &metrics, const search::IDocumentMetaStore &metaStore)
+{
+    LidUsageStats stats = metaStore.getLidUsageStats();
+    metrics.lidLimit.set(stats.getLidLimit());
+    metrics.usedLids.set(stats.getUsedLids());
+    metrics.lowestFreeLid.set(stats.getLowestFreeLid());
+    metrics.highestUsedLid.set(stats.getHighestUsedLid());
+    metrics.lidBloatFactor.set(stats.getLidBloatFactor());
+    metrics.lidFragmentationFactor.set(stats.getLidFragmentationFactor());
+}
+
+}
+
+void
+DocumentDBMetricsUpdater::updateMetrics(DocumentDBMetricsCollection &metrics)
+{
+    MemoryUsage totalMemoryUsage;
+    ExecutorThreadingServiceStats threadingServiceStats = _writeService.getStats();
+    updateLegacyMetrics(metrics.getLegacyMetrics(), threadingServiceStats);
+    updateIndexMetrics(metrics, _subDBs.getReadySubDB()->getSearchableStats(), totalMemoryUsage);
+    updateAttributeMetrics(metrics, _subDBs, totalMemoryUsage);
+    updateMatchingMetrics(metrics, *_subDBs.getReadySubDB());
+    updateSessionCacheMetrics(metrics, _sessionManager);
+    updateDocumentsMetrics(metrics, _subDBs);
+    updateMiscMetrics(metrics.getTaggedMetrics(), threadingServiceStats, totalMemoryUsage);
+    metrics.getTaggedMetrics().totalMemoryUsage.update(totalMemoryUsage);
+}
+
+void
+DocumentDBMetricsUpdater::updateLegacyMetrics(LegacyDocumentDBMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats)
+{
+    metrics.executor.update(threadingServiceStats.getMasterExecutorStats());
+    metrics.summaryExecutor.update(threadingServiceStats.getSummaryExecutorStats());
+    metrics.indexExecutor.update(threadingServiceStats.getIndexExecutorStats());
+    updateDocstoreMetrics(metrics.docstore, _subDBs, _lastDocStoreCacheStats.total);
+
+    DocumentMetaStoreReadGuards dmss(_subDBs);
+    updateLidSpaceMetrics(metrics.ready.docMetaStore, dmss.readydms->get());
+    updateLidSpaceMetrics(metrics.notReady.docMetaStore, dmss.notreadydms->get());
+    updateLidSpaceMetrics(metrics.removed.docMetaStore, dmss.remdms->get());
+
+    metrics.numBadConfigs.set(_state.getDelayedConfig() ? 1u : 0u);
+}
+
+void
+DocumentDBMetricsUpdater::updateAttributeResourceUsageMetrics(DocumentDBTaggedMetrics::AttributeMetrics &metrics)
+{
+    AttributeUsageStats attributeUsageStats = _writeFilter.getAttributeUsageStats();
+    bool feedBlocked = !_writeFilter.acceptWriteOperation();
+    double enumStoreUsed = attributeUsageStats.enumStoreUsage().getUsage().usage();
+    double multiValueUsed = attributeUsageStats.multiValueUsage().getUsage().usage();
+    metrics.resourceUsage.enumStore.set(enumStoreUsed);
+    metrics.resourceUsage.multiValue.set(multiValueUsed);
+    metrics.resourceUsage.feedingBlocked.set(feedBlocked ? 1 : 0);
+}
+
+void
+DocumentDBMetricsUpdater::updateMiscMetrics(DocumentDBTaggedMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats, MemoryUsage &totalMemoryUsage)
+{
+    metrics.threadingService.update(threadingServiceStats);
+    _jobTrackers.updateMetrics(metrics.job);
+
+    updateAttributeResourceUsageMetrics(metrics.attribute);
+    updateDocumentStoreMetrics(metrics.ready.documentStore, _subDBs.getReadySubDB(), _lastDocStoreCacheStats.readySubDb, totalMemoryUsage);
+    updateDocumentStoreMetrics(metrics.removed.documentStore, _subDBs.getRemSubDB(), _lastDocStoreCacheStats.removedSubDb, totalMemoryUsage);
+    updateDocumentStoreMetrics(metrics.notReady.documentStore, _subDBs.getNotReadySubDB(), _lastDocStoreCacheStats.notReadySubDb, totalMemoryUsage);
+
+    DocumentMetaStoreReadGuards dmss(_subDBs);
+    updateLidSpaceMetrics(metrics.ready.lidSpace, dmss.readydms->get());
+    updateLidSpaceMetrics(metrics.notReady.lidSpace, dmss.notreadydms->get());
+    updateLidSpaceMetrics(metrics.removed.lidSpace, dmss.remdms->get());
+}
+
+}
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb_metrics_updater.h b/searchcore/src/vespa/searchcore/proton/server/documentdb_metrics_updater.h
new file mode 100644
index 00000000000..755d429d553
--- /dev/null
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb_metrics_updater.h
@@ -0,0 +1,59 @@
+// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#pragma once
+
+#include <vespa/searchcore/proton/metrics/documentdb_tagged_metrics.h>
+#include <vespa/searchlib/docstore/cachestats.h>
+
+namespace proton {
+
+namespace matching { class SessionManager; }
+
+class AttributeUsageFilter;
+class DDBState;
+class DocumentDBJobTrackers;
+class DocumentDBMetricsCollection;
+class DocumentSubDBCollection;
+class ExecutorThreadingService;
+class ExecutorThreadingServiceStats;
+class LegacyDocumentDBMetrics;
+
+/**
+ * Class used to update metrics for a document db.
+ */
+class DocumentDBMetricsUpdater {
+private:
+    struct DocumentStoreCacheStats {
+        search::CacheStats total;
+        search::CacheStats readySubDb;
+        search::CacheStats notReadySubDb;
+        search::CacheStats removedSubDb;
+        DocumentStoreCacheStats() : total(), readySubDb(), notReadySubDb(), removedSubDb() {}
+    };
+
+    const DocumentSubDBCollection &_subDBs;
+    ExecutorThreadingService &_writeService;
+    DocumentDBJobTrackers &_jobTrackers;
+    matching::SessionManager &_sessionManager;
+    const AttributeUsageFilter &_writeFilter;
+    const DDBState &_state;
+    // Last updated document store cache statistics. Necessary due to metrics implementation is upside down.
+    DocumentStoreCacheStats _lastDocStoreCacheStats;
+
+    void updateLegacyMetrics(LegacyDocumentDBMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats);
+    void updateMiscMetrics(DocumentDBTaggedMetrics &metrics, const ExecutorThreadingServiceStats &threadingServiceStats, search::MemoryUsage &totalMemoryUsage);
+    void updateAttributeResourceUsageMetrics(DocumentDBTaggedMetrics::AttributeMetrics &metrics);
+
+public:
+    DocumentDBMetricsUpdater(const DocumentSubDBCollection &subDBs,
+                             ExecutorThreadingService &writeService,
+                             DocumentDBJobTrackers &jobTrackers,
+                             matching::SessionManager &sessionManager,
+                             const AttributeUsageFilter &writeFilter,
+                             const DDBState &state);
+    ~DocumentDBMetricsUpdater();
+
+    void updateMetrics(DocumentDBMetricsCollection &metrics);
+
+};
+
+}
diff --git a/searchcore/src/vespa/searchcore/proton/server/idocumentsubdb.h b/searchcore/src/vespa/searchcore/proton/server/idocumentsubdb.h
index d41c2088518..736edcf3c5e 100644
--- a/searchcore/src/vespa/searchcore/proton/server/idocumentsubdb.h
+++ b/searchcore/src/vespa/searchcore/proton/server/idocumentsubdb.h
@@ -84,6 +84,7 @@ public:
     virtual const std::shared_ptr<ISummaryAdapter> &getSummaryAdapter() const = 0;
     virtual const std::shared_ptr<IIndexWriter> &getIndexWriter() const = 0;
     virtual IDocumentMetaStoreContext &getDocumentMetaStoreContext() = 0;
+    virtual const IDocumentMetaStoreContext &getDocumentMetaStoreContext() const = 0;
     virtual IFlushTargetList getFlushTargets() = 0;
     virtual size_t getNumDocs() const = 0;
     virtual size_t getNumActiveDocs() const = 0;
diff --git a/searchcore/src/vespa/searchcore/proton/server/storeonlydocsubdb.h b/searchcore/src/vespa/searchcore/proton/server/storeonlydocsubdb.h
index 4a21537f134..a54525377a9 100644
--- a/searchcore/src/vespa/searchcore/proton/server/storeonlydocsubdb.h
+++ b/searchcore/src/vespa/searchcore/proton/server/storeonlydocsubdb.h
@@ -228,6 +228,7 @@ public:
     const ISummaryAdapter::SP & getSummaryAdapter() const override { return _summaryAdapter; }
     const std::shared_ptr<IIndexWriter> & getIndexWriter() const override;
     IDocumentMetaStoreContext & getDocumentMetaStoreContext() override { return *_metaStoreCtx; }
+    const IDocumentMetaStoreContext &getDocumentMetaStoreContext() const override { return *_metaStoreCtx; }
     size_t getNumDocs() const override;
     size_t getNumActiveDocs() const override;
     bool hasDocument(const document::DocumentId &id) override;
diff --git a/searchcore/src/vespa/searchcore/proton/test/dummy_document_sub_db.h b/searchcore/src/vespa/searchcore/proton/test/dummy_document_sub_db.h
index 66ae296566f..c2595a85fb7 100644
--- a/searchcore/src/vespa/searchcore/proton/test/dummy_document_sub_db.h
+++ b/searchcore/src/vespa/searchcore/proton/test/dummy_document_sub_db.h
@@ -67,6 +67,7 @@ struct DummyDocumentSubDb : public IDocumentSubDB
     const ISummaryAdapter::SP &getSummaryAdapter() const override { return _summaryAdapter; }
     const IIndexWriter::SP &getIndexWriter() const override { return _indexWriter; }
     IDocumentMetaStoreContext &getDocumentMetaStoreContext() override { return _metaStoreCtx; }
+    const IDocumentMetaStoreContext &getDocumentMetaStoreContext() const override { return _metaStoreCtx; }
     IFlushTargetList getFlushTargets() override { return IFlushTargetList(); }
     size_t getNumDocs() const override { return 0; }
     size_t getNumActiveDocs() const override { return 0; }