Remove search throttled index setting and thread pool

rest-api-spec/build.gradle

@@ -87,4 +87,5 @@ tasks.named("yamlRestCompatTestTransform").configure ({ task ->
   task.skipTest("indices.create/21_synthetic_source_stored/index param - field ordering", "Synthetic source keep arrays now stores leaf arrays natively")
   task.skipTest("indices.create/21_synthetic_source_stored/field param - keep nested array", "Synthetic source keep arrays now stores leaf arrays natively")
   task.skipTest("indices.create/21_synthetic_source_stored/field param - keep root array", "Synthetic source keep arrays now stores leaf arrays natively")
+  task.skipTest("cluster.info/30_info_thread_pool/Cluster HTTP Info", "The search_throttled thread pool has been removed")
 })

rest-api-spec/src/yamlRestTest/resources/rest-api-spec/test/cluster.info/30_info_thread_pool.yml

@@ -95,13 +95,6 @@
   - gte: { thread_pool.search_coordination.largest: 0 }
   - gte: { thread_pool.search_coordination.completed: 0 }
 
-  - gte: { thread_pool.search_throttled.threads: 0 }
-  - gte: { thread_pool.search_throttled.queue: 0 }
-  - gte: { thread_pool.search_throttled.active: 0 }
-  - gte: { thread_pool.search_throttled.rejected: 0 }
-  - gte: { thread_pool.search_throttled.largest: 0 }
-  - gte: { thread_pool.search_throttled.completed: 0 }
-
   - gte: { thread_pool.snapshot.threads: 0 }
   - gte: { thread_pool.snapshot.queue: 0 }
   - gte: { thread_pool.snapshot.active: 0 }

server/src/main/java/org/elasticsearch/action/explain/TransportExplainAction.java

@@ -46,7 +46,6 @@
 
 import java.io.IOException;
 import java.util.Set;
-import java.util.concurrent.Executor;
 import java.util.function.LongSupplier;
 
 /**
@@ -184,12 +183,4 @@ protected ShardIterator shards(ProjectState state, InternalRequest request) {
         return clusterService.operationRouting()
             .getShards(state, request.concreteIndex(), request.request().id(), request.request().routing(), request.request().preference());
     }
-
-    @Override
-    protected Executor getExecutor(ExplainRequest request, ShardId shardId) {
-        IndexService indexService = searchService.getIndicesService().indexServiceSafe(shardId.getIndex());
-        return indexService.getIndexSettings().isSearchThrottled()
-            ? threadPool.executor(ThreadPool.Names.SEARCH_THROTTLED)
-            : super.getExecutor(request, shardId);
-    }
 }

server/src/main/java/org/elasticsearch/action/get/TransportGetAction.java

@@ -171,8 +171,6 @@ protected Executor getExecutor(GetRequest request, ShardId shardId) {
         final ClusterState clusterState = clusterService.state();
         if (projectResolver.getProjectMetadata(clusterState).getIndexSafe(shardId.getIndex()).isSystem()) {
             return threadPool.executor(executorSelector.executorForGet(shardId.getIndexName()));
-        } else if (indicesService.indexServiceSafe(shardId.getIndex()).getIndexSettings().isSearchThrottled()) {
-            return threadPool.executor(ThreadPool.Names.SEARCH_THROTTLED);
         } else {
             return super.getExecutor(request, shardId);
         }

server/src/main/java/org/elasticsearch/action/get/TransportShardMultiGetAction.java

@@ -160,8 +160,6 @@ protected Executor getExecutor(MultiGetShardRequest request, ShardId shardId) {
         final ClusterState clusterState = clusterService.state();
         if (projectResolver.getProjectMetadata(clusterState).index(shardId.getIndex()).isSystem()) {
             return threadPool.executor(executorSelector.executorForGet(shardId.getIndexName()));
-        } else if (indicesService.indexServiceSafe(shardId.getIndex()).getIndexSettings().isSearchThrottled()) {
-            return threadPool.executor(ThreadPool.Names.SEARCH_THROTTLED);
         } else {
             return super.getExecutor(request, shardId);
         }

server/src/main/java/org/elasticsearch/action/termvectors/TransportShardMultiTermsVectorAction.java

@@ -28,8 +28,6 @@
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 
-import java.util.concurrent.Executor;
-
 import static org.elasticsearch.core.Strings.format;
 
 public class TransportShardMultiTermsVectorAction extends TransportSingleShardAction<
@@ -112,12 +110,4 @@ protected MultiTermVectorsShardResponse shardOperation(MultiTermVectorsShardRequ
 
         return response;
     }
-
-    @Override
-    protected Executor getExecutor(MultiTermVectorsShardRequest request, ShardId shardId) {
-        IndexService indexService = indicesService.indexServiceSafe(shardId.getIndex());
-        return indexService.getIndexSettings().isSearchThrottled()
-            ? threadPool.executor(ThreadPool.Names.SEARCH_THROTTLED)
-            : super.getExecutor(request, shardId);
-    }
 }

server/src/main/java/org/elasticsearch/action/termvectors/TransportTermVectorsAction.java

@@ -28,7 +28,6 @@
 import org.elasticsearch.transport.TransportService;
 
 import java.io.IOException;
-import java.util.concurrent.Executor;
 
 /**
  * Performs the get operation.
@@ -127,12 +126,4 @@ protected TermVectorsResponse shardOperation(TermVectorsRequest request, ShardId
     protected Writeable.Reader<TermVectorsResponse> getResponseReader() {
         return TermVectorsResponse::new;
     }
-
-    @Override
-    protected Executor getExecutor(TermVectorsRequest request, ShardId shardId) {
-        IndexService indexService = indicesService.indexServiceSafe(shardId.getIndex());
-        return indexService.getIndexSettings().isSearchThrottled()
-            ? threadPool.executor(ThreadPool.Names.SEARCH_THROTTLED)
-            : super.getExecutor(request, shardId);
-    }
 }

server/src/main/java/org/elasticsearch/common/settings/IndexScopedSettings.java

@@ -157,7 +157,6 @@ public final class IndexScopedSettings extends AbstractScopedSettings {
                 IndexSettings.INDEX_TRANSLOG_RETENTION_AGE_SETTING,
                 IndexSettings.INDEX_TRANSLOG_RETENTION_SIZE_SETTING,
                 IndexSettings.INDEX_SEARCH_IDLE_AFTER,
-                IndexSettings.INDEX_SEARCH_THROTTLED,
                 IndexFieldDataService.INDEX_FIELDDATA_CACHE_KEY,
                 IndexSettings.IGNORE_ABOVE_SETTING,
                 FieldMapper.IGNORE_MALFORMED_SETTING,

server/src/main/java/org/elasticsearch/index/IndexSettings.java

@@ -538,17 +538,6 @@ public Iterator<Setting<?>> settings() {
         Property.ServerlessPublic
     );
 
-    /**
-     * Marks an index to be searched throttled. This means that never more than one shard of such an index will be searched concurrently
-     */
-    public static final Setting<Boolean> INDEX_SEARCH_THROTTLED = Setting.boolSetting(
-        "index.search.throttled",
-        false,
-        Property.IndexScope,
-        Property.PrivateIndex,
-        Property.Dynamic
-    );
-
     /**
      * Determines a balance between file-based and operations-based peer recoveries. The number of operations that will be used in an
      * operations-based peer recovery is limited to this proportion of the total number of documents in the shard (including deleted
@@ -913,7 +902,6 @@ private void setRetentionLeaseMillis(final TimeValue retentionLease) {
     private volatile int maxTermsCount;
     private volatile String defaultPipeline;
     private volatile String requiredPipeline;
-    private volatile boolean searchThrottled;
     private volatile long mappingNestedFieldsLimit;
     private volatile long mappingNestedDocsLimit;
     private volatile long mappingTotalFieldsLimit;
@@ -1042,7 +1030,6 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
                 this.timestampBounds = TimestampBounds.updateEndTime(this.timestampBounds, endTime);
             });
         }
-        this.searchThrottled = INDEX_SEARCH_THROTTLED.get(settings);
         this.queryStringLenient = QUERY_STRING_LENIENT_SETTING.get(settings);
         this.queryStringAnalyzeWildcard = QUERY_STRING_ANALYZE_WILDCARD.get(nodeSettings);
         this.queryStringAllowLeadingWildcard = QUERY_STRING_ALLOW_LEADING_WILDCARD.get(nodeSettings);
@@ -1200,7 +1187,6 @@ public IndexSettings(final IndexMetadata indexMetadata, final Settings nodeSetti
         scopedSettings.addSettingsUpdateConsumer(DEFAULT_PIPELINE, this::setDefaultPipeline);
         scopedSettings.addSettingsUpdateConsumer(FINAL_PIPELINE, this::setRequiredPipeline);
         scopedSettings.addSettingsUpdateConsumer(INDEX_SOFT_DELETES_RETENTION_OPERATIONS_SETTING, this::setSoftDeleteRetentionOperations);
-        scopedSettings.addSettingsUpdateConsumer(INDEX_SEARCH_THROTTLED, this::setSearchThrottled);
         scopedSettings.addSettingsUpdateConsumer(INDEX_SOFT_DELETES_RETENTION_LEASE_PERIOD_SETTING, this::setRetentionLeaseMillis);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING, this::setMappingNestedFieldsLimit);
         scopedSettings.addSettingsUpdateConsumer(INDEX_MAPPING_NESTED_DOCS_LIMIT_SETTING, this::setMappingNestedDocsLimit);
@@ -1725,18 +1711,6 @@ public long getSoftDeleteRetentionOperations() {
         return this.softDeleteRetentionOperations;
     }
 
-    /**
-     * Returns true if the this index should be searched throttled ie. using the
-     * {@link org.elasticsearch.threadpool.ThreadPool.Names#SEARCH_THROTTLED} thread-pool
-     */
-    public boolean isSearchThrottled() {
-        return searchThrottled;
-    }
-
-    private void setSearchThrottled(boolean searchThrottled) {
-        this.searchThrottled = searchThrottled;
-    }
-
     public long getMappingNestedFieldsLimit() {
         return mappingNestedFieldsLimit;
     }

server/src/main/java/org/elasticsearch/node/NodeConstruction.java

@@ -570,6 +570,14 @@ private static void addBwcSearchWorkerSettings(List<Setting<?>> additionalSettin
         additionalSettings.add(
             Setting.intSetting("thread_pool.search_worker.size", 0, Setting.Property.NodeScope, Setting.Property.DeprecatedWarning)
         );
+        // Search throttled thread pool has been removed in Elasticsearch 9.0.0. These settings are deprecated and take no effect.
+        // They are here only to enable BwC for deployments that still use them
+        additionalSettings.add(
+            Setting.intSetting("thread_pool.search_throttled.queue_size", 0, Setting.Property.NodeScope, Setting.Property.DeprecatedWarning)
+        );
+        additionalSettings.add(
+            Setting.intSetting("thread_pool.search_throttled.size", 0, Setting.Property.NodeScope, Setting.Property.DeprecatedWarning)
+        );
     }
 
     private SearchModule createSearchModule(Settings settings, ThreadPool threadPool, TelemetryProvider telemetryProvider) {

server/src/main/java/org/elasticsearch/rest/action/cat/RestIndicesAction.java

@@ -30,7 +30,6 @@
 import org.elasticsearch.common.time.DateFormatter;
 import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.core.TimeValue;
-import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.Scope;
@@ -125,7 +124,6 @@ public RestResponse buildResponse(Void ignored) throws Exception {
                     .prepareGetSettings(masterNodeTimeout, indices)
                     .setIndicesOptions(indicesOptions)
                     .setMasterNodeTimeout(masterNodeTimeout)
-                    .setNames(IndexSettings.INDEX_SEARCH_THROTTLED.getKey())
                     .execute(listeners.acquire(indexSettingsRef::set));
 
                 // The other requests just provide additional detail, and wildcards may be resolved differently depending on the type of
@@ -488,8 +486,6 @@ protected Table getTableWithHeader(final RestRequest request) {
         table.addCell("memory.total", "sibling:pri;alias:tm,memoryTotal;default:false;text-align:right;desc:total used memory");
         table.addCell("pri.memory.total", "default:false;text-align:right;desc:total user memory");
 
-        table.addCell("search.throttled", "alias:sth;default:false;desc:indicates if the index is search throttled");
-
         table.addCell(
             "bulk.total_operations",
             "sibling:pri;alias:bto,bulkTotalOperation;default:false;text-align:right;desc:number of bulk shard ops"
@@ -568,7 +564,6 @@ Table buildTable(
 
             final IndexMetadata.State indexState = indexMetadata.getState();
             final IndexStats indexStats = indicesStats.get(indexName);
-            final boolean searchThrottled = IndexSettings.INDEX_SEARCH_THROTTLED.get(settings);
 
             final IndexRoutingTable indexRoutingTable = clusterState.routingTable(project.id()).index(indexName);
             final ClusterHealthStatus indexHealthStatus = indexRoutingTable == null
@@ -803,8 +798,6 @@ Table buildTable(
             table.addCell(totalStats.getTotalMemory());
             table.addCell(primaryStats.getTotalMemory());
 
-            table.addCell(searchThrottled);
-
             table.addCell(totalStats.getBulk() == null ? null : totalStats.getBulk().getTotalOperations());
             table.addCell(primaryStats.getBulk() == null ? null : primaryStats.getBulk().getTotalOperations());
 

server/src/main/java/org/elasticsearch/search/SearchService.java

@@ -957,8 +957,6 @@ private Executor getExecutor(IndexShard indexShard) {
         final String executorName;
         if (indexShard.isSystem()) {
             executorName = executorSelector.executorForSearch(indexShard.shardId().getIndexName());
-        } else if (indexShard.indexSettings().isSearchThrottled()) {
-            executorName = Names.SEARCH_THROTTLED;
         } else {
             executorName = Names.SEARCH;
         }

server/src/main/java/org/elasticsearch/threadpool/DefaultBuiltInExecutorBuilders.java

@@ -92,10 +92,6 @@ public Map<String, ExecutorBuilder> getBuilders(Settings settings, int allocated
                 EsExecutors.TaskTrackingConfig.DEFAULT
             )
         );
-        result.put(
-            ThreadPool.Names.SEARCH_THROTTLED,
-            new FixedExecutorBuilder(settings, ThreadPool.Names.SEARCH_THROTTLED, 1, 100, EsExecutors.TaskTrackingConfig.DEFAULT)
-        );
         result.put(
             ThreadPool.Names.MANAGEMENT,
             new ScalingExecutorBuilder(

server/src/main/java/org/elasticsearch/threadpool/ThreadPool.java

@@ -115,8 +115,6 @@ public static class Names {
         public static final String SEARCH = "search";
         public static final String SEARCH_COORDINATION = "search_coordination";
         public static final String AUTO_COMPLETE = "auto_complete";
-        public static final String SEARCH_THROTTLED = "search_throttled";
-
         /**
          * A thread pool for running tasks related to cluster management, including collecting and exposing stats in APIs and certain other
          * internal tasks.
@@ -197,7 +195,6 @@ public static ThreadPoolType fromType(String type) {
         entry(Names.FORCE_MERGE, ThreadPoolType.FIXED),
         entry(Names.FETCH_SHARD_STARTED, ThreadPoolType.SCALING),
         entry(Names.FETCH_SHARD_STORE, ThreadPoolType.SCALING),
-        entry(Names.SEARCH_THROTTLED, ThreadPoolType.FIXED),
         entry(Names.SYSTEM_READ, ThreadPoolType.FIXED),
         entry(Names.SYSTEM_WRITE, ThreadPoolType.FIXED),
         entry(Names.SYSTEM_CRITICAL_READ, ThreadPoolType.FIXED),

server/src/test/java/org/elasticsearch/cluster/metadata/IndexNameExpressionResolverTests.java

@@ -30,7 +30,6 @@
 import org.elasticsearch.core.Tuple;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexNotFoundException;
-import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersion;
 import org.elasticsearch.indices.IndexClosedException;
 import org.elasticsearch.indices.InvalidIndexNameException;
@@ -2279,7 +2278,7 @@ public void testIgnoreThrottled() {
                     .putAlias(AliasMetadata.builder("test-alias"))
             )
             .put(
-                indexBuilder("index", Settings.builder().put(IndexSettings.INDEX_SEARCH_THROTTLED.getKey(), true).build()).state(State.OPEN)
+                indexBuilder("index", Settings.builder().put("index.search.throttled", true).build()).state(State.OPEN)
                     .putAlias(AliasMetadata.builder("test-alias2"))
             )
             .put(

server/src/test/java/org/elasticsearch/rest/action/cat/RestIndicesActionTests.java

@@ -28,7 +28,6 @@
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.Index;
-import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersion;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.test.ESTestCase;
@@ -62,7 +61,6 @@ public void testBuildTable() {
             Settings indexSettings = Settings.builder()
                 .put(IndexMetadata.SETTING_VERSION_CREATED, IndexVersion.current())
                 .put(IndexMetadata.SETTING_INDEX_UUID, UUIDs.randomBase64UUID())
-                .put(IndexSettings.INDEX_SEARCH_THROTTLED.getKey(), randomBoolean())
                 .build();
             indicesSettings.put(indexName, indexSettings);
 

server/src/test/java/org/elasticsearch/search/SearchServiceSingleNodeTests.java

@@ -58,7 +58,6 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.core.AbstractRefCounted;
 import org.elasticsearch.core.TimeValue;
-import org.elasticsearch.index.Index;
 import org.elasticsearch.index.IndexModule;
 import org.elasticsearch.index.IndexNotFoundException;
 import org.elasticsearch.index.IndexService;
@@ -167,7 +166,6 @@
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertHitCount;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertResponse;
-import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSearchHits;
 import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -1846,46 +1844,6 @@ public void testCanRewriteToMatchNone() {
         );
     }
 
-    public void testSetSearchThrottled() throws IOException {
-        createIndex("throttled_threadpool_index");
-        client().execute(
-            InternalOrPrivateSettingsPlugin.UpdateInternalOrPrivateAction.INSTANCE,
-            new InternalOrPrivateSettingsPlugin.UpdateInternalOrPrivateAction.Request(
-                "throttled_threadpool_index",
-                IndexSettings.INDEX_SEARCH_THROTTLED.getKey(),
-                "true"
-            )
-        ).actionGet();
-        final SearchService service = getInstanceFromNode(SearchService.class);
-        Index index = resolveIndex("throttled_threadpool_index");
-        assertTrue(service.getIndicesService().indexServiceSafe(index).getIndexSettings().isSearchThrottled());
-        prepareIndex("throttled_threadpool_index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
-        assertSearchHits(
-            client().prepareSearch("throttled_threadpool_index")
-                .setIndicesOptions(IndicesOptions.STRICT_EXPAND_OPEN_FORBID_CLOSED)
-                .setSize(1),
-            "1"
-        );
-        // we add a search action listener in a plugin above to assert that this is actually used
-        client().execute(
-            InternalOrPrivateSettingsPlugin.UpdateInternalOrPrivateAction.INSTANCE,
-            new InternalOrPrivateSettingsPlugin.UpdateInternalOrPrivateAction.Request(
-                "throttled_threadpool_index",
-                IndexSettings.INDEX_SEARCH_THROTTLED.getKey(),
-                "false"
-            )
-        ).actionGet();
-
-        IllegalArgumentException iae = expectThrows(
-            IllegalArgumentException.class,
-            () -> indicesAdmin().prepareUpdateSettings("throttled_threadpool_index")
-                .setSettings(Settings.builder().put(IndexSettings.INDEX_SEARCH_THROTTLED.getKey(), false))
-                .get()
-        );
-        assertEquals("can not update private setting [index.search.throttled]; this setting is managed by Elasticsearch", iae.getMessage());
-        assertFalse(service.getIndicesService().indexServiceSafe(index).getIndexSettings().isSearchThrottled());
-    }
-
     public void testAggContextGetsMatchAll() throws IOException {
         createIndex("test");
         withAggregationContext("test", context -> assertThat(context.query(), equalTo(new MatchAllDocsQuery())));
@@ -1937,22 +1895,6 @@ private void withAggregationContext(String index, Consumer<AggregationContext> c
         }
     }
 
-    public void testExpandSearchThrottled() {
-        createIndex("throttled_threadpool_index");
-        client().execute(
-            InternalOrPrivateSettingsPlugin.UpdateInternalOrPrivateAction.INSTANCE,
-            new InternalOrPrivateSettingsPlugin.UpdateInternalOrPrivateAction.Request(
-                "throttled_threadpool_index",
-                IndexSettings.INDEX_SEARCH_THROTTLED.getKey(),
-                "true"
-            )
-        ).actionGet();
-
-        prepareIndex("throttled_threadpool_index").setId("1").setSource("field", "value").setRefreshPolicy(IMMEDIATE).get();
-        assertHitCount(client().prepareSearch(), 1L);
-        assertHitCount(client().prepareSearch().setIndicesOptions(IndicesOptions.STRICT_EXPAND_OPEN_FORBID_CLOSED), 1L);
-    }
-
     public void testExpandSearchFrozen() {
         String indexName = "frozen_index";
         createIndex(indexName);