Fix bug in lid space compaction where partial updates to attributes were lost when moving a document.

Instead of using the document store directly (when reading the document to move) the document retriever must be used.
The document retriever patches in attribute values and also correctly waits for the thread writing to the document store.

The job moving documents between the "ready" and "not ready" sub databases was already doing this correctly.

13 files changed, 174 insertions, 118 deletions

diff --git a/searchcore/src/tests/proton/documentdb/documentbucketmover/documentbucketmover_test.cpp b/searchcore/src/tests/proton/documentdb/documentbucketmover/documentbucketmover_test.cpp
index af6a9d38385..10b1c829674 100644
--- a/searchcore/src/tests/proton/documentdb/documentbucketmover/documentbucketmover_test.cpp
+++ b/searchcore/src/tests/proton/documentdb/documentbucketmover/documentbucketmover_test.cpp
@@ -191,7 +191,7 @@ MySubDb::MySubDb(const std::shared_ptr<const DocumentTypeRepo> &repo, std::share
       _metaStore(*_metaStoreSP),
       _realRetriever(std::make_shared<MyDocumentRetriever>(repo)),
       _retriever(_realRetriever),
-      _subDb(_metaStoreSP, _retriever, subDbId), _docs(),
+      _subDb("my_sub_db", subDbId, _metaStoreSP, _retriever, IFeedView::SP()), _docs(),
       _bucketDBHandler(*bucketDB)
 {
     _bucketDBHandler.addDocumentMetaStore(_metaStoreSP.get(), 0);
@@ -238,7 +238,11 @@ struct MoveFixture
     void setupForBucket(const BucketId &bucket,
                         uint32_t sourceSubDbId,
                         uint32_t targetSubDbId) {
-        _source._subDb._subDbId = sourceSubDbId;
+        _source._subDb = MaintenanceDocumentSubDB(_source._subDb.name(),
+                                                  sourceSubDbId,
+                                                  _source._subDb.meta_store(),
+                                                  _source._subDb.retriever(),
+                                                  _source._subDb.feed_view());
         _mover.setupForBucket(bucket, &_source._subDb, targetSubDbId, _handler, _bucketDb);
     }
     void moveDocuments(size_t maxDocsToMove) {
diff --git a/searchcore/src/tests/proton/documentdb/lid_space_compaction/lid_space_compaction_test.cpp b/searchcore/src/tests/proton/documentdb/lid_space_compaction/lid_space_compaction_test.cpp
index 82566025a30..5305ff15003 100644
--- a/searchcore/src/tests/proton/documentdb/lid_space_compaction/lid_space_compaction_test.cpp
+++ b/searchcore/src/tests/proton/documentdb/lid_space_compaction/lid_space_compaction_test.cpp
@@ -160,51 +160,59 @@ struct MyFrozenBucketHandler : public IFrozenBucketHandler
     virtual void removeListener(IBucketFreezeListener *) override { }
 };
 
-struct MyFeedView : public test::DummyFeedView
-{
-    MyFeedView(const std::shared_ptr<const DocumentTypeRepo> &repo)
-        : test::DummyFeedView(repo)
+struct MyFeedView : public test::DummyFeedView {
+    MyFeedView(std::shared_ptr<const DocumentTypeRepo> repo)
+        : test::DummyFeedView(std::move(repo))
     {
     }
 };
 
-struct MyDocumentStore : public test::DummyDocumentStore
-{
+struct MyDocumentStore : public test::DummyDocumentStore {
     Document::SP _readDoc;
     mutable uint32_t _readLid;
     MyDocumentStore() : _readDoc(), _readLid(0) {}
-    virtual document::Document::UP
-    read(search::DocumentIdT lid, const document::DocumentTypeRepo &) const override {
+    ~MyDocumentStore();
+    document::Document::UP read(search::DocumentIdT lid, const document::DocumentTypeRepo &) const override {
         _readLid = lid;
         return Document::UP(_readDoc->clone());
     }
 };
 
-struct MySummaryManager : public test::DummySummaryManager
-{
-    MyDocumentStore _store;
-    MySummaryManager() : _store() {}
-    virtual search::IDocumentStore &getBackingStore() override { return _store; }
-};
+MyDocumentStore::~MyDocumentStore() = default;
 
-struct MySubDb : public test::DummyDocumentSubDb
-{
-    std::shared_ptr<const DocumentTypeRepo> _repo;
-    MySubDb(const std::shared_ptr<const DocumentTypeRepo> &repo, std::shared_ptr<BucketDBOwner> bucketDB);
-    ~MySubDb();
-    virtual IFeedView::SP getFeedView() const override {
-        return IFeedView::SP(new MyFeedView(_repo));
+struct MyDocumentRetriever : public DocumentRetrieverBaseForTest {
+    std::shared_ptr<const DocumentTypeRepo> repo;
+    const MyDocumentStore& store;
+    MyDocumentRetriever(std::shared_ptr<const DocumentTypeRepo> repo_in, const MyDocumentStore& store_in)
+        : repo(repo_in),
+          store(store_in)
+    {
+    }
+    const document::DocumentTypeRepo& getDocumentTypeRepo() const override { return *repo; }
+    void getBucketMetaData(const storage::spi::Bucket&, DocumentMetaData::Vector& ) const override { abort(); }
+    DocumentMetaData getDocumentMetaData(const DocumentId& ) const override { abort(); }
+    Document::UP getDocument(DocumentIdT lid) const override {
+        return store.read(lid, *repo);
     }
+    CachedSelect::SP parseSelect(const vespalib::string &) const override { abort(); }
 };
 
+struct MySubDb {
+    test::DummyDocumentSubDb sub_db;
+    MaintenanceDocumentSubDB maintenance_sub_db;
+    MySubDb(std::shared_ptr<BucketDBOwner> bucket_db, const MyDocumentStore& store, std::shared_ptr<const DocumentTypeRepo> repo);
+    ~MySubDb();
+};
 
-MySubDb::MySubDb(const std::shared_ptr<const DocumentTypeRepo> &repo, std::shared_ptr<BucketDBOwner> bucketDB)
-    : test::DummyDocumentSubDb(bucketDB, SUBDB_ID),
-      _repo(repo)
+MySubDb::MySubDb(std::shared_ptr<BucketDBOwner> bucket_db, const MyDocumentStore& store, std::shared_ptr<const DocumentTypeRepo> repo)
+    : sub_db(std::move(bucket_db), SUBDB_ID),
+      maintenance_sub_db(sub_db.getName(), sub_db.getSubDbId(), sub_db.getDocumentMetaStoreContext().getSP(),
+                         std::make_shared<MyDocumentRetriever>(repo, store),
+                         std::make_shared<MyFeedView>(repo))
 {
-    _summaryManager.reset(new MySummaryManager());
 }
-MySubDb::~MySubDb() {}
+
+MySubDb::~MySubDb() = default;
 
 struct MyDirectJobRunner : public IMaintenanceJobRunner {
     IMaintenanceJob &_job;
@@ -350,17 +358,15 @@ struct HandlerFixture
 {
     DocBuilder _docBuilder;
     std::shared_ptr<BucketDBOwner> _bucketDB;
+    MyDocumentStore _docStore;
     MySubDb _subDb;
-    MySummaryManager &_summaryMgr;
-    MyDocumentStore &_docStore;
     LidSpaceCompactionHandler _handler;
     HandlerFixture()
         : _docBuilder(Schema()),
           _bucketDB(std::make_shared<BucketDBOwner>()),
-          _subDb(_docBuilder.getDocumentTypeRepo(), _bucketDB),
-          _summaryMgr(static_cast<MySummaryManager &>(*_subDb.getSummaryManager())),
-          _docStore(_summaryMgr._store),
-          _handler(_subDb, "test")
+          _docStore(),
+          _subDb(_bucketDB, _docStore, _docBuilder.getDocumentTypeRepo()),
+          _handler(_subDb.maintenance_sub_db, "test")
     {
         _docStore._readDoc = _docBuilder.startDocument(DOC_ID).endDocument();
     }
diff --git a/searchcore/src/tests/proton/documentdb/maintenancecontroller/maintenancecontroller_test.cpp b/searchcore/src/tests/proton/documentdb/maintenancecontroller/maintenancecontroller_test.cpp
index c3974368e54..a4f2aeb767d 100644
--- a/searchcore/src/tests/proton/documentdb/maintenancecontroller/maintenancecontroller_test.cpp
+++ b/searchcore/src/tests/proton/documentdb/maintenancecontroller/maintenancecontroller_test.cpp
@@ -523,9 +523,10 @@ MyDocumentSubDB::getSubDB()
 {
     IDocumentRetriever::SP retriever(new MyDocumentRetriever(*this));
 
-    return MaintenanceDocumentSubDB(_metaStoreSP,
+    return MaintenanceDocumentSubDB("my_sub_db", _subDBId,
+                                    _metaStoreSP,
                                     retriever,
-                                    _subDBId);
+                                    IFeedView::SP());
 }
 
 
diff --git a/searchcore/src/vespa/searchcore/proton/server/bucketmovejob.cpp b/searchcore/src/vespa/searchcore/proton/server/bucketmovejob.cpp
index cb929e0a6c7..4848c5a5d47 100644
--- a/searchcore/src/vespa/searchcore/proton/server/bucketmovejob.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/bucketmovejob.cpp
@@ -88,9 +88,9 @@ BucketMoveJob::checkBucket(const BucketId &bucket,
     const MaintenanceDocumentSubDB &source(wantReady ? _notReady : _ready);
     const MaintenanceDocumentSubDB &target(wantReady ? _ready : _notReady);
     LOG(debug, "checkBucket(): mover.setupForBucket(%s, source:%u, target:%u)",
-        bucket.toString().c_str(), source._subDbId, target._subDbId);
-    mover.setupForBucket(bucket, &source, target._subDbId,
-                         _moveHandler, _ready._metaStore->getBucketDB());
+        bucket.toString().c_str(), source.sub_db_id(), target.sub_db_id());
+    mover.setupForBucket(bucket, &source, target.sub_db_id(),
+                         _moveHandler, _ready.meta_store()->getBucketDB());
 }
 
 BucketMoveJob::ScanResult
@@ -98,7 +98,7 @@ BucketMoveJob::scanBuckets(size_t maxBucketsToScan, IFrozenBucketHandler::Exclus
 {
     size_t bucketsScanned = 0;
     bool passDone = false;
-    ScanIterator itr(_ready._metaStore->getBucketDB().takeGuard(),
+    ScanIterator itr(_ready.meta_store()->getBucketDB().takeGuard(),
             _scanPass, _scanPos._lastBucket, _endPos._lastBucket);
     BucketId bucket;
     for (; itr.valid() &&
@@ -250,7 +250,7 @@ BucketMoveJob::deactivateBucket(BucketId bucket)
 void
 BucketMoveJob::activateBucket(BucketId bucket)
 {
-    BucketDBOwner::Guard notReadyBdb(_notReady._metaStore->getBucketDB().takeGuard());
+    BucketDBOwner::Guard notReadyBdb(_notReady.meta_store()->getBucketDB().takeGuard());
     if (notReadyBdb->get(bucket).getDocumentCount() == 0) {
         return; // notready bucket already empty. This is the normal case.
     }
@@ -291,7 +291,7 @@ BucketMoveJob::scanAndMove(size_t maxBucketsToScan,
     while (!_delayedBuckets.empty() && _delayedMover.bucketDone()) {
         const BucketId bucket = *_delayedBuckets.begin();
         _delayedBuckets.erase(_delayedBuckets.begin());
-        ScanIterator itr(_ready._metaStore->getBucketDB().takeGuard(), bucket);
+        ScanIterator itr(_ready.meta_store()->getBucketDB().takeGuard(), bucket);
         if (itr.getBucket() == bucket) {
             checkBucket(bucket, itr, _delayedMover, bucketGuard);
         }
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentbucketmover.cpp b/searchcore/src/vespa/searchcore/proton/server/documentbucketmover.cpp
index 3c73532fbba..d6d8ba03a67 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentbucketmover.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/documentbucketmover.cpp
@@ -24,12 +24,12 @@ DocumentBucketMover::moveDocument(DocumentIdT lid,
                                   const document::GlobalId &gid,
                                   Timestamp timestamp)
 {
-    Document::SP doc(_source->_retriever->getDocument(lid).release());
+    Document::SP doc(_source->retriever()->getDocument(lid).release());
     if (!doc || doc->getId().getGlobalId() != gid)
         return; // Failed to retrieve document, removed or changed identity
     // TODO(geirst): what if doc is NULL?
     BucketId bucketId = _bucket.stripUnused();
-    MoveOperation op(bucketId, timestamp, doc, DbDocumentId(_source->_subDbId, lid), _targetSubDbId);
+    MoveOperation op(bucketId, timestamp, doc, DbDocumentId(_source->sub_db_id(), lid), _targetSubDbId);
 
     // We cache the bucket for the document we are going to move to avoid getting
     // inconsistent bucket info (getBucketInfo()) while moving between ready and not-ready
@@ -103,16 +103,16 @@ DocumentBucketMover::moveDocuments(size_t maxDocsToMove)
     if (_bucketDone) {
         return;
     }
-    Iterator itr = (_lastGidValid ? _source->_metaStore->upperBound(_lastGid)
-                    : _source->_metaStore->lowerBound(_bucket));
-    const Iterator end = _source->_metaStore->upperBound(_bucket);
+    Iterator itr = (_lastGidValid ? _source->meta_store()->upperBound(_lastGid)
+                    : _source->meta_store()->lowerBound(_bucket));
+    const Iterator end = _source->meta_store()->upperBound(_bucket);
     size_t docsMoved = 0;
     size_t docsSkipped = 0; // In absence of a proper cost metric
     typedef std::vector<MoveKey> MoveVec;
     MoveVec toMove;
     for (; itr != end && docsMoved < maxDocsToMove; ++itr) {
         DocumentIdT lid = itr.getKey();
-        const RawDocumentMetaData &metaData = _source->_metaStore->getRawMetaData(lid);
+        const RawDocumentMetaData &metaData = _source->meta_store()->getRawMetaData(lid);
         if (metaData.getBucketUsedBits() != _bucket.getUsedBits()) {
             ++docsSkipped;
             if (docsSkipped >= 50) {
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp b/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
index 16e8d7ae90a..2729dbe01a5 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdb.cpp
@@ -1,5 +1,6 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
+#include "bootstrapconfig.h"
 #include "combiningfeedview.h"
 #include "commit_and_wait_document_retriever.h"
 #include "document_meta_store_read_guards.h"
@@ -7,29 +8,29 @@
 #include "documentdb.h"
 #include "documentdbconfigscout.h"
 #include "idocumentdbowner.h"
+#include "idocumentsubdb.h"
 #include "lid_space_compaction_handler.h"
 #include "maintenance_jobs_injector.h"
 #include "reconfig_params.h"
-#include "bootstrapconfig.h"
 #include <vespa/document/repo/documenttyperepo.h>
-#include <vespa/searchcore/proton/metrics/executor_threading_service_stats.h>
+#include <vespa/searchcommon/common/schemaconfigurer.h>
 #include <vespa/searchcore/proton/attribute/attribute_writer.h>
 #include <vespa/searchcore/proton/attribute/imported_attributes_repo.h>
 #include <vespa/searchcore/proton/common/eventlogger.h>
 #include <vespa/searchcore/proton/common/statusreport.h>
+#include <vespa/searchcore/proton/docsummary/isummarymanager.h>
 #include <vespa/searchcore/proton/feedoperation/noopoperation.h>
 #include <vespa/searchcore/proton/index/index_writer.h>
 #include <vespa/searchcore/proton/initializer/task_runner.h>
+#include <vespa/searchcore/proton/metrics/executor_threading_service_stats.h>
 #include <vespa/searchcore/proton/metrics/metricswireservice.h>
-#include <vespa/searchcore/proton/reference/i_document_db_reference_resolver.h>
-#include <vespa/searchcore/proton/reference/i_document_db_reference_registry.h>
 #include <vespa/searchcore/proton/reference/document_db_reference_resolver.h>
-#include <vespa/searchcore/proton/docsummary/isummarymanager.h>
+#include <vespa/searchcore/proton/reference/i_document_db_reference_registry.h>
+#include <vespa/searchcore/proton/reference/i_document_db_reference_resolver.h>
 #include <vespa/searchlib/attribute/attributefactory.h>
 #include <vespa/searchlib/attribute/configconverter.h>
 #include <vespa/searchlib/engine/docsumreply.h>
 #include <vespa/searchlib/engine/searchreply.h>
-#include <vespa/searchcommon/common/schemaconfigurer.h>
 #include <vespa/vespalib/io/fileutil.h>
 #include <vespa/vespalib/util/closuretask.h>
 #include <vespa/vespalib/util/exceptions.h>
@@ -205,9 +206,12 @@ DocumentDB::DocumentDB(const vespalib::string &baseDir,
     _clusterStateHandler.addClusterStateChangedHandler(this);
     // Forward changes of cluster state to bucket handler
     _clusterStateHandler.addClusterStateChangedHandler(&_bucketHandler);
-    for (auto subDb : _subDBs) {
-        _lidSpaceCompactionHandlers.push_back(std::make_unique<LidSpaceCompactionHandler>(*subDb, _docTypeName.getName()));
-    }
+
+    // Lid space compaction handlers are added in the same order as sub dbs are defined in DocumentSubDbCollection.
+    _lidSpaceCompactionHandlers.push_back(std::make_unique<LidSpaceCompactionHandler>(_maintenanceController.getReadySubDB(), _docTypeName.getName()));
+    _lidSpaceCompactionHandlers.push_back(std::make_unique<LidSpaceCompactionHandler>(_maintenanceController.getRemSubDB(), _docTypeName.getName()));
+    _lidSpaceCompactionHandlers.push_back(std::make_unique<LidSpaceCompactionHandler>(_maintenanceController.getNotReadySubDB(), _docTypeName.getName()));
+
     _writeFilter.setConfig(loaded_config->getMaintenanceConfigSP()->getAttributeUsageFilterConfig());
     fastos::TimeStamp visibilityDelay = loaded_config->getMaintenanceConfigSP()->getVisibilityDelay();
     _visibility.setVisibilityDelay(visibilityDelay);
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentsubdbcollection.cpp b/searchcore/src/vespa/searchcore/proton/server/documentsubdbcollection.cpp
index 70e548e8c05..682719436f1 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentsubdbcollection.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/documentsubdbcollection.cpp
@@ -139,18 +139,21 @@ wrapRetriever(const IDocumentRetriever::SP &retriever, ICommitable &commit)
 
 void DocumentSubDBCollection::maintenanceSync(MaintenanceController &mc, ICommitable &commit) {
     RetrieversSP retrievers = getRetrievers();
-    MaintenanceDocumentSubDB readySubDB(
-            getReadySubDB()->getDocumentMetaStoreContext().getSP(),
-            wrapRetriever((*retrievers)[_readySubDbId], commit),
-            _readySubDbId);
-    MaintenanceDocumentSubDB remSubDB(
-            getRemSubDB()->getDocumentMetaStoreContext().getSP(),
-            (*retrievers)[_remSubDbId],
-            _remSubDbId);
-    MaintenanceDocumentSubDB notReadySubDB(
-            getNotReadySubDB()->getDocumentMetaStoreContext().getSP(),
-            wrapRetriever((*retrievers)[_notReadySubDbId], commit),
-            _notReadySubDbId);
+    MaintenanceDocumentSubDB readySubDB(getReadySubDB()->getName(),
+                                        _readySubDbId,
+                                        getReadySubDB()->getDocumentMetaStoreContext().getSP(),
+                                        wrapRetriever((*retrievers)[_readySubDbId], commit),
+                                        getReadySubDB()->getFeedView());
+    MaintenanceDocumentSubDB remSubDB(getRemSubDB()->getName(),
+                                      _remSubDbId,
+                                      getRemSubDB()->getDocumentMetaStoreContext().getSP(),
+                                      (*retrievers)[_remSubDbId],
+                                      getRemSubDB()->getFeedView());
+    MaintenanceDocumentSubDB notReadySubDB(getNotReadySubDB()->getName(),
+                                           _notReadySubDbId,
+                                           getNotReadySubDB()->getDocumentMetaStoreContext().getSP(),
+                                           wrapRetriever((*retrievers)[_notReadySubDbId], commit),
+                                           getNotReadySubDB()->getFeedView());
     mc.syncSubDBs(readySubDB, remSubDB, notReadySubDB);
 }
 
diff --git a/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.cpp b/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.cpp
index a77aa302fea..c4dc26a0875 100644
--- a/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.cpp
@@ -16,8 +16,8 @@ using storage::spi::Timestamp;
 
 namespace proton {
 
-LidSpaceCompactionHandler::LidSpaceCompactionHandler(IDocumentSubDB &subDb,
-                                                     const vespalib::string &docTypeName)
+LidSpaceCompactionHandler::LidSpaceCompactionHandler(const MaintenanceDocumentSubDB& subDb,
+                                                     const vespalib::string& docTypeName)
     : _subDb(subDb),
       _docTypeName(docTypeName)
 {
@@ -26,27 +26,24 @@ LidSpaceCompactionHandler::LidSpaceCompactionHandler(IDocumentSubDB &subDb,
 LidUsageStats
 LidSpaceCompactionHandler::getLidStatus() const
 {
-    return _subDb.getDocumentMetaStoreContext().get().getLidUsageStats();
+    return _subDb.meta_store()->getLidUsageStats();
 }
 
 IDocumentScanIterator::UP
 LidSpaceCompactionHandler::getIterator() const
 {
-    return IDocumentScanIterator::UP(new DocumentScanIterator(
-            _subDb.getDocumentMetaStoreContext().get()));
+    return std::make_unique<DocumentScanIterator>(*_subDb.meta_store());
 }
 
 MoveOperation::UP
 LidSpaceCompactionHandler::createMoveOperation(const search::DocumentMetaData &document, uint32_t moveToLid) const
 {
-    IFeedView::SP feedView = _subDb.getFeedView();
-    const ISummaryManager::SP &summaryMan = _subDb.getSummaryManager();
     const uint32_t moveFromLid = document.lid;
-    Document::UP doc = summaryMan->getBackingStore().read(moveFromLid, *feedView->getDocumentTypeRepo());
-    MoveOperation::UP op(new MoveOperation(document.bucketId, document.timestamp,
-                                           Document::SP(doc.release()),
-                                           DbDocumentId(_subDb.getSubDbId(), moveFromLid),
-                                           _subDb.getSubDbId()));
+    auto doc = _subDb.retriever()->getDocument(moveFromLid);
+    auto op = std::make_unique<MoveOperation>(document.bucketId, document.timestamp,
+                                              Document::SP(doc.release()),
+                                              DbDocumentId(_subDb.sub_db_id(), moveFromLid),
+                                              _subDb.sub_db_id());
     op->setTargetLid(moveToLid);
     return op;
 }
@@ -54,14 +51,14 @@ LidSpaceCompactionHandler::createMoveOperation(const search::DocumentMetaData &d
 void
 LidSpaceCompactionHandler::handleMove(const MoveOperation& op, IDestructorCallback::SP doneCtx)
 {
-    _subDb.getFeedView()->handleMove(op, std::move(doneCtx));
+    _subDb.feed_view()->handleMove(op, std::move(doneCtx));
 }
 
 void
 LidSpaceCompactionHandler::handleCompactLidSpace(const CompactLidSpaceOperation &op)
 {
-    assert(_subDb.getSubDbId() == op.getSubDbId());
-    _subDb.getFeedView()->handleCompactLidSpace(op);
+    assert(_subDb.sub_db_id() == op.getSubDbId());
+    _subDb.feed_view()->handleCompactLidSpace(op);
 }
 
 } // namespace proton
diff --git a/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.h b/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.h
index 0861513a909..21d20001923 100644
--- a/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.h
+++ b/searchcore/src/vespa/searchcore/proton/server/lid_space_compaction_handler.h
@@ -2,7 +2,7 @@
 #pragma once
 
 #include "i_lid_space_compaction_handler.h"
-#include "idocumentsubdb.h"
+#include "maintenancedocumentsubdb.h"
 
 namespace proton {
 
@@ -12,18 +12,18 @@ namespace proton {
 class LidSpaceCompactionHandler : public ILidSpaceCompactionHandler
 {
 private:
-    IDocumentSubDB  &_subDb;
+    const MaintenanceDocumentSubDB& _subDb;
     vespalib::string _docTypeName;
 
 public:
-    LidSpaceCompactionHandler(IDocumentSubDB &subDb,
-                              const vespalib::string &docTypeName);
+    LidSpaceCompactionHandler(const MaintenanceDocumentSubDB& subDb,
+                              const vespalib::string& docTypeName);
 
     // Implements ILidSpaceCompactionHandler
     virtual vespalib::string getName() const override {
-        return _docTypeName + "." + _subDb.getName();
+        return _docTypeName + "." + _subDb.name();
     }
-    virtual uint32_t getSubDbId() const override { return _subDb.getSubDbId(); }
+    virtual uint32_t getSubDbId() const override { return _subDb.sub_db_id(); }
     virtual search::LidUsageStats getLidStatus() const override;
     virtual IDocumentScanIterator::UP getIterator() const override;
     virtual MoveOperation::UP createMoveOperation(const search::DocumentMetaData &document, uint32_t moveToLid) const override;
diff --git a/searchcore/src/vespa/searchcore/proton/server/maintenance_jobs_injector.cpp b/searchcore/src/vespa/searchcore/proton/server/maintenance_jobs_injector.cpp
index 744ce2aa7f4..6b130dfa144 100644
--- a/searchcore/src/vespa/searchcore/proton/server/maintenance_jobs_injector.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/maintenance_jobs_injector.cpp
@@ -111,8 +111,8 @@ MaintenanceJobsInjector::injectJobs(MaintenanceController &controller,
         controller.registerJobInMasterThread(MUP(new DocumentDBCommitJob(commit, config.getVisibilityDelay())));
     }
     const MaintenanceDocumentSubDB &mRemSubDB(controller.getRemSubDB());
-    MUP pruneRDjob(new PruneRemovedDocumentsJob(config.getPruneRemovedDocumentsConfig(), *mRemSubDB._metaStore,
-                                                mRemSubDB._subDbId, docTypeName, prdHandler, fbHandler));
+    MUP pruneRDjob(new PruneRemovedDocumentsJob(config.getPruneRemovedDocumentsConfig(), *mRemSubDB.meta_store(),
+                                                mRemSubDB.sub_db_id(), docTypeName, prdHandler, fbHandler));
     controller.registerJobInMasterThread(
             trackJob(jobTrackers.getRemovedDocumentsPrune(), std::move(pruneRDjob)));
     if (!config.getLidSpaceCompactionConfig().isDisabled()) {
diff --git a/searchcore/src/vespa/searchcore/proton/server/maintenancecontroller.cpp b/searchcore/src/vespa/searchcore/proton/server/maintenancecontroller.cpp
index 79135d27e5c..e6afb8a19b2 100644
--- a/searchcore/src/vespa/searchcore/proton/server/maintenancecontroller.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/maintenancecontroller.cpp
@@ -197,6 +197,19 @@ MaintenanceController::newConfig(const DocumentDBMaintenanceConfig::SP &config)
     restart();
 }
 
+namespace {
+
+void
+assert_equal_meta_store_instances(const MaintenanceDocumentSubDB& old_db,
+                                  const MaintenanceDocumentSubDB& new_db)
+{
+    if (old_db.valid() && new_db.valid()) {
+        assert(old_db.meta_store().get() == new_db.meta_store().get());
+    }
+}
+
+}
+
 void
 MaintenanceController::syncSubDBs(const MaintenanceDocumentSubDB &readySubDB,
                                   const MaintenanceDocumentSubDB &remSubDB,
@@ -206,11 +219,16 @@ MaintenanceController::syncSubDBs(const MaintenanceDocumentSubDB &readySubDB,
     bool oldValid = _readySubDB.valid();
     assert(readySubDB.valid());
     assert(remSubDB.valid());
+    // Document meta store instances should not change. Maintenance jobs depend on this fact.
+    assert_equal_meta_store_instances(_readySubDB, readySubDB);
+    assert_equal_meta_store_instances(_remSubDB, remSubDB);
+    assert_equal_meta_store_instances(_notReadySubDB, notReadySubDB);
     _readySubDB = readySubDB;
     _remSubDB = remSubDB;
     _notReadySubDB = notReadySubDB;
-    if (!oldValid && _started)
+    if (!oldValid && _started) {
         restart();
+    }
 }
 
 
diff --git a/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.cpp b/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.cpp
index ffaea1ff576..6b781eb8e0f 100644
--- a/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.cpp
@@ -5,26 +5,37 @@
 namespace proton {
 
 MaintenanceDocumentSubDB::MaintenanceDocumentSubDB()
-    : _metaStore(),
-      _retriever(),
-      _subDbId(0u)
-{ }
+    : _name(""),
+      _sub_db_id(0),
+      _meta_store(nullptr),
+      _retriever(nullptr),
+      _feed_view(nullptr)
+{
+}
 
-MaintenanceDocumentSubDB::~MaintenanceDocumentSubDB() { }
+MaintenanceDocumentSubDB::~MaintenanceDocumentSubDB() = default;
 
-MaintenanceDocumentSubDB::MaintenanceDocumentSubDB(const IDocumentMetaStore::SP & metaStore,
-                                                   const IDocumentRetriever::SP & retriever,
-                                                   uint32_t subDbId)
-    : _metaStore(metaStore),
-      _retriever(retriever),
-      _subDbId(subDbId)
-{ }
+MaintenanceDocumentSubDB::MaintenanceDocumentSubDB(const vespalib::string& name,
+                                                   uint32_t sub_db_id,
+                                                   IDocumentMetaStore::SP meta_store,
+                                                   IDocumentRetriever::SP retriever,
+                                                   IFeedView::SP feed_view)
+    : _name(name),
+      _sub_db_id(sub_db_id),
+      _meta_store(std::move(meta_store)),
+      _retriever(std::move(retriever)),
+      _feed_view(std::move(feed_view))
+{
+}
 
 void
-MaintenanceDocumentSubDB::clear() {
-    _metaStore.reset();
+MaintenanceDocumentSubDB::clear()
+{
+    _name = "";
+    _sub_db_id = 0;
+    _meta_store.reset();
     _retriever.reset();
-    _subDbId = 0u;
-} 
+    _feed_view.reset();
+}
 
-} // namespace proton
+}
diff --git a/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.h b/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.h
index 41c43d910d7..bfe73f361b6 100644
--- a/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.h
+++ b/searchcore/src/vespa/searchcore/proton/server/maintenancedocumentsubdb.h
@@ -2,6 +2,7 @@
 
 #pragma once
 
+#include "ifeedview.h"
 #include <vespa/searchcore/proton/documentmetastore/i_document_meta_store.h>
 #include <vespa/searchcore/proton/persistenceengine/i_document_retriever.h>
 
@@ -13,19 +14,30 @@ namespace proton {
  */
 class MaintenanceDocumentSubDB
 {
-public:
-    IDocumentMetaStore::SP   _metaStore;
-    IDocumentRetriever::SP   _retriever;
-    uint32_t                 _subDbId;
+private:
+    vespalib::string       _name;
+    uint32_t               _sub_db_id;
+    IDocumentMetaStore::SP _meta_store;
+    IDocumentRetriever::SP _retriever;
+    IFeedView::SP          _feed_view;
 
+public:
     MaintenanceDocumentSubDB();
     ~MaintenanceDocumentSubDB();
 
-    MaintenanceDocumentSubDB(const IDocumentMetaStore::SP & metaStore,
-                             const IDocumentRetriever::SP & retriever,
-                             uint32_t subDbId);
+    MaintenanceDocumentSubDB(const vespalib::string& name,
+                             uint32_t sub_db_id,
+                             IDocumentMetaStore::SP meta_store,
+                             IDocumentRetriever::SP retriever,
+                             IFeedView::SP feed_view);
+
+    const vespalib::string& name() const { return _name; }
+    uint32_t sub_db_id() const { return _sub_db_id; }
+    const IDocumentMetaStore::SP& meta_store() const { return _meta_store; }
+    const IDocumentRetriever::SP& retriever() const { return _retriever; }
+    const IFeedView::SP& feed_view() const { return _feed_view; }
 
-    bool valid() const { return bool(_metaStore); }
+    bool valid() const { return _meta_store.get() != nullptr; }
 
     void clear();
 };