Merge pull request #3675 from vespa-engine/balder/summary.numthreads-2-backgroundnumthreads-rebased-1

Balder/summary.numthreads 2 backgroundnumthreads rebased 1

18 files changed, 114 insertions, 84 deletions

diff --git a/config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilder.java b/config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilder.java
index ba89169fc4c..4ea638ca41a 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilder.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilder.java
@@ -74,6 +74,8 @@ public class DomSearchTuningBuilder extends VespaDomBuilder.DomConfigProducerBui
                 handleSummary(parent, e, t.searchNode);
             } else if (equals("initialize", e)) {
                 handleInitialize(e, t.searchNode);
+            } else if (equals("background", e)) {
+                handleBackground(e, t.searchNode);
             }
         }
     }
@@ -251,6 +253,9 @@ public class DomSearchTuningBuilder extends VespaDomBuilder.DomConfigProducerBui
             } else if (equals("minfilesizefactor", e)) {
                 s.logStore.minFileSizeFactor = asDouble(e);
             } else if (equals("numthreads", e)) {
+                parent.deployLogger().log(Level.WARNING,
+                        "Element 'numthreads is deprecated. Use background.threads instead." +
+                                " For now it will take max of the two.");
                 s.logStore.numThreads = asInt(e);
             } else if (equals("chunk", e)) {
                 s.logStore.chunk = new Tuning.SearchNode.Summary.Store.Component(true);
@@ -268,4 +273,13 @@ public class DomSearchTuningBuilder extends VespaDomBuilder.DomConfigProducerBui
         }
     }
 
+    private void handleBackground(Element spec, Tuning.SearchNode sn) {
+        sn.background = new Tuning.SearchNode.Background();
+        for (Element e : XML.getChildren(spec)) {
+            if (equals("threads", e)) {
+                sn.background.threads = asInt(e);
+            }
+        }
+    }
+
 }
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java b/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java
index 5750db08178..6cfd52cc232 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/search/NodeFlavorTuning.java
@@ -27,7 +27,7 @@ public class NodeFlavorTuning implements ProtonConfig.Producer {
         setHwInfo(builder);
         tuneDiskWriteSpeed(builder);
         tuneDocumentStoreMaxFileSize(builder.summary.log);
-        tuneDocumentStoreNumThreads(builder.summary.log);
+        tuneDocumentStoreNumThreads(builder.background);
         tuneFlushStrategyMemoryLimits(builder.flush.memory);
         tuneFlushStrategyTlsSize(builder.flush.memory);
     }
@@ -56,8 +56,8 @@ public class NodeFlavorTuning implements ProtonConfig.Producer {
         builder.maxfilesize(fileSizeBytes);
     }
 
-    private void tuneDocumentStoreNumThreads(ProtonConfig.Summary.Log.Builder builder) {
-        builder.numthreads(max(8, (int)nodeFlavor.getMinCpuCores()/2));
+    private void tuneDocumentStoreNumThreads(ProtonConfig.Background.Builder builder) {
+        builder.threads(max(8, (int)nodeFlavor.getMinCpuCores()/2));
     }
 
     private void tuneFlushStrategyMemoryLimits(ProtonConfig.Flush.Memory.Builder builder) {
diff --git a/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java b/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java
index 17af4030cb6..1e3b1783f9b 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/search/Tuning.java
@@ -334,6 +334,17 @@ public class Tuning extends AbstractConfigProducer implements PartitionsConfig.P
             }
         }
 
+        public static class Background implements ProtonConfig.Producer {
+            public Integer threads = null;
+
+            @Override
+            public void getConfig(ProtonConfig.Builder builder) {
+                if (threads != null) {
+                    builder.background.threads(threads);
+                }
+            }
+        }
+
         public RequestThreads threads = null;
         public FlushStrategy strategy = null;
         public Resizing resizing = null;
@@ -341,6 +352,7 @@ public class Tuning extends AbstractConfigProducer implements PartitionsConfig.P
         public Attribute attribute = null;
         public Summary summary = null;
         public Initialize initialize = null;
+        public Background background = null;
 
         @Override
         public void getConfig(ProtonConfig.Builder builder) {
@@ -351,6 +363,7 @@ public class Tuning extends AbstractConfigProducer implements PartitionsConfig.P
             if (attribute != null) attribute.getConfig(builder);
             if (summary != null) summary.getConfig(builder);
             if (initialize != null) initialize.getConfig(builder);
+            if (background != null) background.getConfig(builder);
         }
     }
 
diff --git a/config-model/src/main/resources/schema/content.rnc b/config-model/src/main/resources/schema/content.rnc
index 9031e8128df..e75c15ea524 100644
--- a/config-model/src/main/resources/schema/content.rnc
+++ b/config-model/src/main/resources/schema/content.rnc
@@ -353,6 +353,9 @@ Tuning = element tuning {
       }? &
       element initialize {
          element threads { xsd:nonNegativeInteger }?
+      }? &
+      element background {
+         element threads { xsd:nonNegativeInteger }?
       }?
    }?
 }
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilderTest.java b/config-model/src/test/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilderTest.java
index 613827d2cf1..210334a1f23 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilderTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/builder/xml/dom/DomSearchTuningBuilderTest.java
@@ -233,4 +233,14 @@ public class DomSearchTuningBuilderTest extends DomBuilderTest {
         assertThat(cfg, containsString("initialize.threads 7"));
     }
 
+    @Test
+    public void requireThatWeCanParseBackgroundTag() {
+        Tuning t = createTuning(parseXml("<background>",
+                "<threads>7</threads>",
+                "</background>"));
+        assertEquals(7, t.searchNode.background.threads.intValue());
+        String cfg = getProtonCfg(t);
+        assertThat(cfg, containsString("background.threads 7"));
+    }
+
 }
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java b/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java
index 0e1ad92c70d..75f6abb2542 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/search/NodeFlavorTuningTest.java
@@ -97,7 +97,7 @@ public class NodeFlavorTuningTest {
     }
 
     private static void assertDocumentStoreNumThreads(int numThreads, double numCores) {
-        assertEquals(numThreads, configFromNumCoresSetting(numCores).summary().log().numthreads());
+        assertEquals(numThreads, configFromNumCoresSetting(numCores).background().threads());
     }
 
     private static void assertFlushStrategyTlsSize(long expTlsSizeBytes, int diskGb) {
diff --git a/searchcore/src/vespa/searchcore/config/proton.def b/searchcore/src/vespa/searchcore/config/proton.def
index 594a8717d7f..8c01c45dac8 100644
--- a/searchcore/src/vespa/searchcore/config/proton.def
+++ b/searchcore/src/vespa/searchcore/config/proton.def
@@ -256,6 +256,8 @@ summary.log.maxbucketspread double default=2.5
 summary.log.minfilesizefactor double default=0.2
 
 ## Number of threads used for compressing incomming documents/compacting.
+## Deprecated. Use background.threads instead.
+## TODO Remove
 summary.log.numthreads int default=8 restart
 
 ## Control io options during flush of stored documents.
@@ -376,6 +378,11 @@ visit.ignoremaxbytes bool default=true
 ## When set to 0 (default) we use 1 separate thread per document database.
 initialize.threads int default = 0
 
+## Number of worker threads doing background compaction/compression tasks.
+## They all live i a shared thread pool.
+## When set to 0 (default), it will have enough threads to saturate half of the cores.
+background.threads int default=0
+
 ## Portion of enumstore address space that can be used before put and update
 ## portion of feed is blocked.
 writefilter.attribute.enumstorelimit double default = 0.9
diff --git a/searchcore/src/vespa/searchcore/proton/server/documentdbconfigmanager.cpp b/searchcore/src/vespa/searchcore/proton/server/documentdbconfigmanager.cpp
index f45fc658129..6aea5234fbe 100644
--- a/searchcore/src/vespa/searchcore/proton/server/documentdbconfigmanager.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/documentdbconfigmanager.cpp
@@ -170,9 +170,8 @@ deriveConfig(const ProtonConfig::Summary & summary, const ProtonConfig::Flush::M
     logConfig.setMaxFileSize(log.maxfilesize)
             .setMaxDiskBloatFactor(std::min(flush.diskbloatfactor, flush.each.diskbloatfactor))
             .setMaxBucketSpread(log.maxbucketspread).setMinFileSizeFactor(log.minfilesizefactor)
-            .setNumThreads(log.numthreads).compact2ActiveFile(log.compact2activefile)
-            .compactCompression(deriveCompression(log.compact.compression)).setFileConfig(fileConfig)
-            .disableCrcOnRead(chunk.skipcrconread);
+            .compact2ActiveFile(log.compact2activefile).compactCompression(deriveCompression(log.compact.compression))
+            .setFileConfig(fileConfig).disableCrcOnRead(chunk.skipcrconread);
     return LogDocumentStore::Config(config, logConfig);
 }
 
diff --git a/searchcore/src/vespa/searchcore/proton/server/proton.cpp b/searchcore/src/vespa/searchcore/proton/server/proton.cpp
index 7caed5198bd..5863c03226c 100644
--- a/searchcore/src/vespa/searchcore/proton/server/proton.cpp
+++ b/searchcore/src/vespa/searchcore/proton/server/proton.cpp
@@ -85,12 +85,24 @@ diskMemUsageSamplerConfig(const ProtonConfig &proton, const HwInfo &hwInfo)
             hwInfo);
 }
 
+size_t
+deriveBackgroundThreads(const ProtonConfig & proton) {
+    size_t threads = std::thread::hardware_concurrency();
+    if (proton.background.threads != 0) {
+        threads = proton.background.threads;
+    }
+    threads = std::max(threads, size_t(proton.summary.log.numthreads));
+
+    // We need at least 1 guaranteed free worker in order to ensure progress so #documentsdbs + 1 should suffice,
+    // but we will not be cheap and give #documentsdbs * 2
+    return std::max(threads, proton.documentdb.size() * 2);;
 }
 
-static const vespalib::string CUSTOM_COMPONENT_API_PATH = "/state/v1/custom/component";
+const vespalib::string CUSTOM_COMPONENT_API_PATH = "/state/v1/custom/component";
 
-Proton::ProtonFileHeaderContext::ProtonFileHeaderContext(const Proton &proton_,
-        const vespalib::string &creator)
+}
+
+Proton::ProtonFileHeaderContext::ProtonFileHeaderContext(const Proton &proton_, const vespalib::string &creator)
     : _proton(proton_),
       _hostName(),
       _creator(creator),
@@ -208,7 +220,7 @@ Proton::init()
 {
     assert( ! _initStarted && ! _initComplete );
     _initStarted = true;
-    if (_threadPool.NewThread(&_clock, NULL) == NULL) {
+    if (_threadPool.NewThread(&_clock, nullptr) == nullptr) {
         throw IllegalStateException("Failed starting thread for the cheap clock");
     }
     _protonConfigFetcher.start();
@@ -234,8 +246,7 @@ Proton::init(const BootstrapConfig::SP & configSnapshot)
                                      hwDiskCfg.samplewritesize,
                                      hwDiskCfg.shared,
                                      hwMemoryCfg.size);
-    _hwInfoSampler = std::make_unique<HwInfoSampler>(protonConfig.basedir,
-                                                     samplerCfg);
+    _hwInfoSampler = std::make_unique<HwInfoSampler>(protonConfig.basedir, samplerCfg);
     _hwInfo = _hwInfoSampler->hwInfo();
     setFS4Compression(protonConfig);
     _diskMemUsageSampler = std::make_unique<DiskMemUsageSampler>
@@ -244,8 +255,7 @@ Proton::init(const BootstrapConfig::SP & configSnapshot)
 
     _metricsEngine.reset(new MetricsEngine());
     _metricsEngine->addMetricsHook(_metricsHook);
-    _fileHeaderContext.setClusterName(protonConfig.clustername,
-                                      protonConfig.basedir);
+    _fileHeaderContext.setClusterName(protonConfig.clustername, protonConfig.basedir);
     _tls.reset(new TLS(_configUri.createWithNewId(protonConfig.tlsconfigid), _fileHeaderContext));
     _matchEngine.reset(new MatchEngine(protonConfig.numsearcherthreads,
                                        protonConfig.numthreadspersearch,
@@ -257,7 +267,7 @@ Proton::init(const BootstrapConfig::SP & configSnapshot)
     const ProtonConfig::Flush & flush(protonConfig.flush);
     switch (flush.strategy) {
     case ProtonConfig::Flush::MEMORY: {
-        MemoryFlush::SP memoryFlush = std::make_shared<MemoryFlush>(
+        auto memoryFlush = std::make_shared<MemoryFlush>(
                 MemoryFlushConfigUpdater::convertConfig(flush.memory), fastos::ClockSystem::now());
         _memoryFlushConfigUpdater = std::make_unique<MemoryFlushConfigUpdater>(memoryFlush, flush.memory);
         _diskMemUsageSampler->notifier().addDiskMemUsageListener(_memoryFlushConfigUpdater.get());
@@ -290,14 +300,12 @@ Proton::init(const BootstrapConfig::SP & configSnapshot)
 
     vespalib::string fileConfigId;
     _warmupExecutor.reset(new vespalib::ThreadStackExecutor(4, 128*1024));
-    // We need at least 1 guaranteed free worker in order to ensure progress so #documentsdbs + 1 should suffice,
-    // but we will not be cheap and give #documentsdbs * 2
-    const size_t summaryThreads = std::max(size_t(protonConfig.summary.log.numthreads), protonConfig.documentdb.size() * 2);
+
+    const size_t summaryThreads = deriveBackgroundThreads(protonConfig);
     _summaryExecutor.reset(new vespalib::BlockingThreadStackExecutor(summaryThreads, 128*1024, summaryThreads*16));
     InitializeThreads initializeThreads;
     if (protonConfig.initialize.threads > 0) {
-        initializeThreads = std::make_shared<vespalib::ThreadStackExecutor>
-                            (protonConfig.initialize.threads, 128 * 1024);
+        initializeThreads = std::make_shared<vespalib::ThreadStackExecutor>(protonConfig.initialize.threads, 128 * 1024);
         _initDocumentDbsInSequence = (protonConfig.initialize.threads == 1);
     }
     _protonConfigurer.applyInitialConfig(initializeThreads);
@@ -563,10 +571,8 @@ Proton::addDocumentDB(const document::DocumentType &docType,
     try {
         ret->start();
     } catch (vespalib::Exception &e) {
-        LOG(warning,
-            "Failed to start database for document type '%s'; %s",
-            docTypeName.toString().c_str(),
-            e.what());
+        LOG(warning, "Failed to start database for document type '%s'; %s",
+            docTypeName.toString().c_str(), e.what());
         return DocumentDB::SP();
     }
     // Wait for replay done on document dbs added due to reconfigs, since engines are already up and running.
@@ -577,14 +583,12 @@ Proton::addDocumentDB(const document::DocumentType &docType,
     _metricsEngine->addDocumentDBMetrics(ret->getMetricsCollection());
     _metricsEngine->addMetricsHook(ret->getMetricsUpdateHook());
     _documentDBMap[docTypeName] = ret;
-    if (_persistenceEngine.get() != NULL) {
+    if (_persistenceEngine) {
         // Not allowed to get to service layer to call pause().
         std::unique_lock<std::shared_timed_mutex> persistenceWGuard(_persistenceEngine->getWLock());
-        PersistenceHandlerProxy::SP
-            persistenceHandler(new PersistenceHandlerProxy(ret));
+        auto persistenceHandler = std::make_shared<PersistenceHandlerProxy>(ret);
         if (!_isInitializing) {
-            _persistenceEngine->
-                propagateSavedClusterState(*persistenceHandler);
+            _persistenceEngine->propagateSavedClusterState(*persistenceHandler);
             _persistenceEngine->populateInitialBucketDB(bucketSpace, *persistenceHandler);
         }
         // TODO: Fix race with new cluster state setting.
@@ -649,10 +653,7 @@ Proton::ping(MonitorRequest::UP request, MonitorClient & client)
     BootstrapConfig::SP configSnapshot = getActiveConfigSnapshot();
     const ProtonConfig &protonConfig = configSnapshot->getProtonConfig();
     ret.partid = protonConfig.partition;
-    if (_matchEngine->isOnline())
-        ret.timestamp = 42; // change to flush caches on tld/qrs
-    else
-        ret.timestamp = 0;
+    ret.timestamp = (_matchEngine->isOnline()) ? 42 : 0;
     ret.activeDocs = getNumActiveDocs();
     ret.activeDocsRequested = request->reportActiveDocs;
     return reply;
@@ -661,7 +662,7 @@ Proton::ping(MonitorRequest::UP request, MonitorClient & client)
 bool
 Proton::triggerFlush()
 {
-    if ((_flushEngine.get() == NULL) || ! _flushEngine->HasThread()) {
+    if (!_flushEngine || ! _flushEngine->HasThread()) {
         return false;
     }
     _flushEngine->triggerFlush();
@@ -682,13 +683,12 @@ createPrepareRestartConfig(const ProtonConfig &protonConfig)
 bool
 Proton::prepareRestart()
 {
-    if ((_flushEngine.get() == NULL) || ! _flushEngine->HasThread()) {
+    if (!_flushEngine || ! _flushEngine->HasThread()) {
         return false;
     }
     BootstrapConfig::SP configSnapshot = getActiveConfigSnapshot();
-    IFlushStrategy::SP strategy =
-            std::make_shared<PrepareRestartFlushStrategy>(
-                    createPrepareRestartConfig(configSnapshot->getProtonConfig()));
+    auto strategy = std::make_shared<PrepareRestartFlushStrategy>(
+            createPrepareRestartConfig(configSnapshot->getProtonConfig()));
     _flushEngine->setStrategy(strategy);
     return true;
 }
@@ -700,7 +700,7 @@ int countOpenFiles()
     static const char * const fd_dir_name = "/proc/self/fd";
     int count = 0;
     DIR *dp = opendir(fd_dir_name);
-    if (dp != NULL) {
+    if (dp != nullptr) {
         struct dirent *ptr;
         while ((ptr = readdir(dp)) != nullptr) {
             if (strcmp(".", ptr->d_name) == 0) continue;
@@ -738,10 +738,6 @@ Proton::updateMetrics(const vespalib::MonitorGuard &)
     }
 }
 
-namespace {
-const std::string config_id_tag = "CONFIG ID";
-}  // namespace
-
 void
 Proton::waitForInitDone()
 {
diff --git a/searchlib/src/apps/docstore/benchmarkdatastore.cpp b/searchlib/src/apps/docstore/benchmarkdatastore.cpp
index 3dcfbbb31cc..620a139d451 100644
--- a/searchlib/src/apps/docstore/benchmarkdatastore.cpp
+++ b/searchlib/src/apps/docstore/benchmarkdatastore.cpp
@@ -99,7 +99,7 @@ BenchmarkDataStoreApp::benchmark(const vespalib::string & dir, size_t numReads,
         tuning._randRead.setWantMemoryMap();
     }
     search::index::DummyFileHeaderContext fileHeaderContext;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     transactionlog::NoSyncProxy noTlSyncer;
     LogDataStore store(executor, dir, config, growStrategy, tuning,
                        fileHeaderContext,
diff --git a/searchlib/src/apps/docstore/documentstoreinspect.cpp b/searchlib/src/apps/docstore/documentstoreinspect.cpp
index b7f202f1209..40f603c3da1 100644
--- a/searchlib/src/apps/docstore/documentstoreinspect.cpp
+++ b/searchlib/src/apps/docstore/documentstoreinspect.cpp
@@ -105,7 +105,7 @@ DocumentStoreInspectApp::verify(const vespalib::string & dir)
     GrowStrategy growStrategy;
     TuneFileSummary tuning;
     search::index::DummyFileHeaderContext fileHeaderContext;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     transactionlog::NoSyncProxy noTlSyncer;
 
     LogDataStore store(executor, dir, config, growStrategy, tuning,
diff --git a/searchlib/src/apps/docstore/verifylogdatastore.cpp b/searchlib/src/apps/docstore/verifylogdatastore.cpp
index 1fb83248b5b..498516882c1 100644
--- a/searchlib/src/apps/docstore/verifylogdatastore.cpp
+++ b/searchlib/src/apps/docstore/verifylogdatastore.cpp
@@ -49,7 +49,7 @@ VerifyLogDataStoreApp::verify(const vespalib::string & dir)
     GrowStrategy growStrategy;
     TuneFileSummary tuning;
     search::index::DummyFileHeaderContext fileHeaderContext;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     transactionlog::NoSyncProxy noTlSyncer;
 
     try {
diff --git a/searchlib/src/apps/tests/biglogtest.cpp b/searchlib/src/apps/tests/biglogtest.cpp
index b5eb76d40a7..788fb855c7f 100644
--- a/searchlib/src/apps/tests/biglogtest.cpp
+++ b/searchlib/src/apps/tests/biglogtest.cpp
@@ -134,7 +134,7 @@ factory<LogDataStore>::factory(std::string dir)
     : DioTune(),
       _fileHeaderContext(),
       _config(),
-      _executor(_config.getNumThreads(), 128*1024),
+      _executor(1, 128*1024),
       _noTlSyncer(),
       _datastore(_executor, dir, _config, GrowStrategy(), tuning, _fileHeaderContext, _noTlSyncer, NULL)
 {}
diff --git a/searchlib/src/tests/docstore/document_store/document_store_test.cpp b/searchlib/src/tests/docstore/document_store/document_store_test.cpp
index b48d754bfb5..2ab24a00557 100644
--- a/searchlib/src/tests/docstore/document_store/document_store_test.cpp
+++ b/searchlib/src/tests/docstore/document_store/document_store_test.cpp
@@ -77,7 +77,7 @@ TEST("require that LogDocumentStore::Config equality operator detects inequality
     EXPECT_TRUE(C() == C());
     EXPECT_FALSE(C() != C());
     EXPECT_FALSE(C(DC(CompressionConfig::NONE, 100000, 100), LC()) == C());
-    EXPECT_FALSE(C(DC(), LC().setNumThreads(7)) == C());
+    EXPECT_FALSE(C(DC(), LC().setMaxBucketSpread(7)) == C());
 }
 
 TEST_MAIN() { TEST_RUN_ALL(); }
diff --git a/searchlib/src/tests/docstore/document_store_visitor/document_store_visitor_test.cpp b/searchlib/src/tests/docstore/document_store_visitor/document_store_visitor_test.cpp
index 7e4b4fa4363..247ee134854 100644
--- a/searchlib/src/tests/docstore/document_store_visitor/document_store_visitor_test.cpp
+++ b/searchlib/src/tests/docstore/document_store_visitor/document_store_visitor_test.cpp
@@ -234,9 +234,9 @@ Fixture::Fixture()
     : _baseDir("visitor"),
       _repo(makeDocTypeRepoConfig()),
       _storeConfig(DocumentStore::Config(CompressionConfig::NONE, 0, 0),
-                   LogDataStore::Config().setMaxFileSize(50000).setMaxBucketSpread(3.0).setNumThreads(1)
+                   LogDataStore::Config().setMaxFileSize(50000).setMaxBucketSpread(3.0)
                            .setFileConfig(WriteableFileChunk::Config(CompressionConfig(), 16384))),
-      _executor(_storeConfig.getLogConfig().getNumThreads(), 128 * 1024),
+      _executor(1, 128 * 1024),
       _fileHeaderContext(),
       _tlSyncer(),
       _store(),
diff --git a/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp b/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp
index c7da0c17c80..ed99003c2f7 100644
--- a/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp
+++ b/searchlib/src/tests/docstore/logdatastore/logdatastore_test.cpp
@@ -205,9 +205,9 @@ TEST("testGrowing") {
     LogDataStore::Config config; //(100000, 0.1, 3.0, 0.2, 8, true, CompressionConfig::LZ4,
                                 // WriteableFileChunk::Config(CompressionConfig(CompressionConfig::LZ4, 9, 60), 1000));
     config.setMaxFileSize(100000).setMaxDiskBloatFactor(0.1).setMaxBucketSpread(3.0).setMinFileSizeFactor(0.2)
-            .setNumThreads(8).compact2ActiveFile(true).compactCompression({CompressionConfig::LZ4})
+            .compact2ActiveFile(true).compactCompression({CompressionConfig::LZ4})
             .setFileConfig({{CompressionConfig::LZ4, 9, 60}, 1000});
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(8, 128*1024);
     DummyFileHeaderContext fileHeaderContext;
     MyTlSyncer tlSyncer;
     {
@@ -276,30 +276,26 @@ void fetchAndTest(IDataStore & datastore, uint32_t lid, const void *a, size_t sz
 TEST("testTruncatedIdxFile"){
     LogDataStore::Config config;
     DummyFileHeaderContext fileHeaderContext;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     MyTlSyncer tlSyncer;
     {
         // Files comes from the 'growing test'.
-        LogDataStore datastore(executor,
-                               TEST_PATH("bug-7257706"), config,
-                               GrowStrategy(), TuneFileSummary(),
-                               fileHeaderContext, tlSyncer, NULL);
+        LogDataStore datastore(executor, TEST_PATH("bug-7257706"), config, GrowStrategy(),
+                               TuneFileSummary(), fileHeaderContext, tlSyncer, NULL);
         EXPECT_EQUAL(354ul, datastore.lastSyncToken());
     }
     const char * magic = "mumbo jumbo";
     {
-        LogDataStore datastore(executor, "bug-7257706-truncated", config,
-                               GrowStrategy(), TuneFileSummary(),
-                               fileHeaderContext, tlSyncer, NULL);
+        LogDataStore datastore(executor, "bug-7257706-truncated", config, GrowStrategy(),
+                               TuneFileSummary(), fileHeaderContext, tlSyncer, NULL);
         EXPECT_EQUAL(331ul, datastore.lastSyncToken());
         datastore.write(332, 7, magic, strlen(magic));
         datastore.write(333, 8, magic, strlen(magic));
         datastore.flush(datastore.initFlush(334));
     }
     {
-        LogDataStore datastore(executor, "bug-7257706-truncated", config,
-                               GrowStrategy(), TuneFileSummary(),
-                               fileHeaderContext, tlSyncer, NULL);
+        LogDataStore datastore(executor, "bug-7257706-truncated", config, GrowStrategy(),
+                               TuneFileSummary(), fileHeaderContext, tlSyncer, NULL);
         EXPECT_EQUAL(334ul, datastore.lastSyncToken());
     }
 }
@@ -307,7 +303,7 @@ TEST("testTruncatedIdxFile"){
 TEST("testThatEmptyIdxFilesAndDanglingDatFilesAreRemoved") {
     LogDataStore::Config config;
     DummyFileHeaderContext fileHeaderContext;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     MyTlSyncer tlSyncer;
     LogDataStore datastore(executor, "dangling-test", config,
                            GrowStrategy(), TuneFileSummary(),
@@ -320,7 +316,7 @@ TEST("testThatEmptyIdxFilesAndDanglingDatFilesAreRemoved") {
 TEST("testThatIncompleteCompactedFilesAreRemoved") {
     LogDataStore::Config config;
     DummyFileHeaderContext fileHeaderContext;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     MyTlSyncer tlSyncer;
     LogDataStore datastore(executor, "incompletecompact-test", config,
                            GrowStrategy(), TuneFileSummary(),
@@ -340,11 +336,10 @@ public:
         _myDir("visitcache"),
         _config(),
         _fileHeaderContext(),
-        _executor(_config.getNumThreads(), 128*1024),
+        _executor(1, 128*1024),
         _tlSyncer(),
-        _datastore(_executor, _myDir.getDir(), _config,
-                           GrowStrategy(), TuneFileSummary(),
-                           _fileHeaderContext, _tlSyncer, NULL)
+        _datastore(_executor, _myDir.getDir(), _config, GrowStrategy(),
+                   TuneFileSummary(), _fileHeaderContext, _tlSyncer, NULL)
     { }
     ~VisitStore();
     IDataStore & getStore() { return _datastore; }
@@ -518,10 +513,10 @@ VisitCacheStore::VisitCacheStore() :
     _myDir("visitcache"),
     _repo(makeDocTypeRepoConfig()),
     _config(DocumentStore::Config(CompressionConfig::LZ4, 1000000, 0).allowVisitCaching(true),
-            LogDataStore::Config().setMaxFileSize(50000).setMaxBucketSpread(3.0).setNumThreads(1)
+            LogDataStore::Config().setMaxFileSize(50000).setMaxBucketSpread(3.0)
                     .setFileConfig(WriteableFileChunk::Config(CompressionConfig(), 16384))),
     _fileHeaderContext(),
-    _executor(_config.getLogConfig().getNumThreads(), 128*1024),
+    _executor(1, 128*1024),
     _tlSyncer(),
     _datastore(_executor, _myDir.getDir(), _config, GrowStrategy(),
                TuneFileSummary(), _fileHeaderContext, _tlSyncer, nullptr),
@@ -596,11 +591,10 @@ TEST("testWriteRead") {
     {
         EXPECT_TRUE(FastOS_File::MakeDirectory("empty"));
         DummyFileHeaderContext fileHeaderContext;
-        vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+        vespalib::ThreadStackExecutor executor(1, 128*1024);
         MyTlSyncer tlSyncer;
-        LogDataStore datastore(executor, "empty", config,
-                               GrowStrategy(), TuneFileSummary(),
-                               fileHeaderContext, tlSyncer, NULL);
+        LogDataStore datastore(executor, "empty", config, GrowStrategy(),
+                               TuneFileSummary(), fileHeaderContext, tlSyncer, NULL);
         ASSERT_TRUE(datastore.lastSyncToken() == 0);
         size_t headerFootprint = datastore.getDiskHeaderFootprint();
         EXPECT_LESS(0u, headerFootprint);
@@ -633,7 +627,7 @@ TEST("testWriteRead") {
     }
     {
         DummyFileHeaderContext fileHeaderContext;
-        vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+        vespalib::ThreadStackExecutor executor(1, 128*1024);
         MyTlSyncer tlSyncer;
         LogDataStore datastore(executor, "empty", config,
                                GrowStrategy(), TuneFileSummary(),
@@ -684,7 +678,7 @@ TEST("requireThatFlushTimeIsAvailableAfterFlush") {
     fastos::TimeStamp before(fastos::ClockSystem::now());
     DummyFileHeaderContext fileHeaderContext;
     LogDataStore::Config config;
-    vespalib::ThreadStackExecutor executor(config.getNumThreads(), 128*1024);
+    vespalib::ThreadStackExecutor executor(1, 128*1024);
     MyTlSyncer tlSyncer;
     LogDataStore store(executor, testDir.getDir(), config, GrowStrategy(),
                        TuneFileSummary(), fileHeaderContext, tlSyncer, nullptr);
@@ -980,7 +974,6 @@ TEST("require that config equality operator detects inequality") {
     EXPECT_FALSE(C() == C().setMaxDiskBloatFactor(0.3));
     EXPECT_FALSE(C() == C().setMaxBucketSpread(0.3));
     EXPECT_FALSE(C() == C().setMinFileSizeFactor(0.3));
-    EXPECT_FALSE(C() == C().setNumThreads(3));
     EXPECT_FALSE(C() == C().setFileConfig(WriteableFileChunk::Config({}, 70)));
     EXPECT_FALSE(C() == C().disableCrcOnRead(true));
     EXPECT_FALSE(C() == C().compact2ActiveFile(false));
diff --git a/searchlib/src/vespa/searchlib/docstore/logdatastore.cpp b/searchlib/src/vespa/searchlib/docstore/logdatastore.cpp
index 6c2509c53c5..4e3178fcdb1 100644
--- a/searchlib/src/vespa/searchlib/docstore/logdatastore.cpp
+++ b/searchlib/src/vespa/searchlib/docstore/logdatastore.cpp
@@ -34,7 +34,6 @@ LogDataStore::Config::Config()
       _maxDiskBloatFactor(0.2),
       _maxBucketSpread(2.5),
       _minFileSizeFactor(0.2),
-      _numThreads(8),
       _skipCrcOnRead(false),
       _compact2ActiveFile(true),
       _compactCompression(CompressionConfig::LZ4),
@@ -49,7 +48,6 @@ LogDataStore::Config::operator == (const Config & rhs) const {
             (_minFileSizeFactor == rhs._minFileSizeFactor) &&
             (_compact2ActiveFile == rhs._compact2ActiveFile) &&
             (_skipCrcOnRead == rhs._skipCrcOnRead) &&
-            (_numThreads == rhs._numThreads) &&
             (_compactCompression == rhs._compactCompression) &&
             (_fileConfig == rhs._fileConfig);
 }
diff --git a/searchlib/src/vespa/searchlib/docstore/logdatastore.h b/searchlib/src/vespa/searchlib/docstore/logdatastore.h
index 5928602e196..52d78cac2bd 100644
--- a/searchlib/src/vespa/searchlib/docstore/logdatastore.h
+++ b/searchlib/src/vespa/searchlib/docstore/logdatastore.h
@@ -43,7 +43,6 @@ public:
         Config & setMaxBucketSpread(double v) { _maxBucketSpread = v; return *this; }
         Config & setMinFileSizeFactor(double v) { _minFileSizeFactor = v; return *this; }
 
-        Config & setNumThreads(size_t v) { _numThreads = v; return *this; }
         Config & compactCompression(CompressionConfig v) { _compactCompression = v; return *this; }
         Config & setFileConfig(WriteableFileChunk::Config v) { _fileConfig = v; return *this; }
 
@@ -52,7 +51,6 @@ public:
         double getMaxBucketSpread() const { return _maxBucketSpread; }
         double getMinFileSizeFactor() const { return _minFileSizeFactor; }
 
-        size_t getNumThreads() const { return _numThreads; }
         bool crcOnReadDisabled() const { return _skipCrcOnRead; }
         bool compact2ActiveFile() const { return _compact2ActiveFile; }
         const CompressionConfig & compactCompression() const { return _compactCompression; }
@@ -67,7 +65,6 @@ public:
         double                      _maxDiskBloatFactor;
         double                      _maxBucketSpread;
         double                      _minFileSizeFactor;
-        size_t                      _numThreads;
         bool                        _skipCrcOnRead;
         bool                        _compact2ActiveFile;
         CompressionConfig           _compactCompression;