Misc speedups to query execution (#112836)

* use array for compound listeners
* Fix capturing lambda for timestamp update
* misc cleanups

Author: original-brownbear

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

@@ -738,14 +738,15 @@ public SearchExecutionContext newSearchExecutionContext(
             clusterService,
             expressionResolver
         );
+        var mapperService = mapperService();
         return new SearchExecutionContext(
             shardId,
             shardRequestIndex,
             indexSettings,
             indexCache.bitsetFilterCache(),
             this::loadFielddata,
-            mapperService(),
-            mapperService().mappingLookup(),
+            mapperService,
+            mapperService.mappingLookup(),
             similarityService(),
             scriptService,
             parserConfiguration,
@@ -781,7 +782,7 @@ public QueryRewriteContext newQueryRewriteContext(
             expressionResolver
         );
         final MapperService mapperService = mapperService();
-        final MappingLookup mappingLookup = mapperService().mappingLookup();
+        final MappingLookup mappingLookup = mapperService.mappingLookup();
         return new QueryRewriteContext(
             parserConfiguration,
             client,

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -3982,12 +3982,11 @@ && isSearchIdle()
                     engine.maybePruneDeletes(); // try to prune the deletes in the engine if we accumulated some
                     setRefreshPending(engine);
                     l.onResponse(false);
-                    return;
                 } else {
                     logger.trace("scheduledRefresh: refresh with source [schedule]");
                     engine.maybeRefresh("schedule", l.map(Engine.RefreshResult::refreshed));
-                    return;
                 }
+                return;
             }
             logger.trace("scheduledRefresh: no refresh needed");
             engine.maybePruneDeletes(); // try to prune the deletes in the engine if we accumulated some

server/src/main/java/org/elasticsearch/index/shard/SearchOperationListener.java

@@ -107,11 +107,11 @@ default void validateReaderContext(ReaderContext readerContext, TransportRequest
      * A Composite listener that multiplexes calls to each of the listeners methods.
      */
     final class CompositeListener implements SearchOperationListener {
-        private final List<SearchOperationListener> listeners;
+        private final SearchOperationListener[] listeners;
         private final Logger logger;
 
         CompositeListener(List<SearchOperationListener> listeners, Logger logger) {
-            this.listeners = listeners;
+            this.listeners = listeners.toArray(new SearchOperationListener[0]);
             this.logger = logger;
         }
 

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

@@ -462,19 +462,22 @@ public void beforeIndexShardCreated(ShardRouting routing, Settings indexSettings
     }
 
     protected void putReaderContext(ReaderContext context) {
-        final ReaderContext previous = activeReaders.put(context.id().getId(), context);
+        final long id = context.id().getId();
+        final ReaderContext previous = activeReaders.put(id, context);
         assert previous == null;
         // ensure that if we race against afterIndexRemoved, we remove the context from the active list.
         // this is important to ensure store can be cleaned up, in particular if the search is a scroll with a long timeout.
         final Index index = context.indexShard().shardId().getIndex();
         if (indicesService.hasIndex(index) == false) {
-            removeReaderContext(context.id().getId());
+            removeReaderContext(id);
             throw new IndexNotFoundException(index);
         }
     }
 
     protected ReaderContext removeReaderContext(long id) {
-        logger.trace("removing reader context [{}]", id);
+        if (logger.isTraceEnabled()) {
+            logger.trace("removing reader context [{}]", id);
+        }
         return activeReaders.remove(id);
     }
 
@@ -651,12 +654,10 @@ private void searchReady() {
 
     private IndexShard getShard(ShardSearchRequest request) {
         final ShardSearchContextId contextId = request.readerId();
-        if (contextId != null) {
-            if (sessionId.equals(contextId.getSessionId())) {
-                final ReaderContext readerContext = activeReaders.get(contextId.getId());
-                if (readerContext != null) {
-                    return readerContext.indexShard();
-                }
+        if (contextId != null && sessionId.equals(contextId.getSessionId())) {
+            final ReaderContext readerContext = activeReaders.get(contextId.getId());
+            if (readerContext != null) {
+                return readerContext.indexShard();
             }
         }
         return indicesService.indexServiceSafe(request.shardId().getIndex()).getShard(request.shardId().id());
@@ -970,13 +971,11 @@ final ReaderContext createOrGetReaderContext(ShardSearchRequest request) {
                 }
                 return createAndPutReaderContext(request, indexService, shard, searcherSupplier, defaultKeepAlive);
             }
-        } else {
-            final long keepAliveInMillis = getKeepAlive(request);
-            final IndexService indexService = indicesService.indexServiceSafe(request.shardId().getIndex());
-            final IndexShard shard = indexService.getShard(request.shardId().id());
-            final Engine.SearcherSupplier searcherSupplier = shard.acquireSearcherSupplier();
-            return createAndPutReaderContext(request, indexService, shard, searcherSupplier, keepAliveInMillis);
         }
+        final long keepAliveInMillis = getKeepAlive(request);
+        final IndexService indexService = indicesService.indexServiceSafe(request.shardId().getIndex());
+        final IndexShard shard = indexService.getShard(request.shardId().id());
+        return createAndPutReaderContext(request, indexService, shard, shard.acquireSearcherSupplier(), keepAliveInMillis);
     }
 
     final ReaderContext createAndPutReaderContext(
@@ -989,19 +988,15 @@ final ReaderContext createAndPutReaderContext(
         ReaderContext readerContext = null;
         Releasable decreaseScrollContexts = null;
         try {
+            final ShardSearchContextId id = new ShardSearchContextId(sessionId, idGenerator.incrementAndGet());
             if (request.scroll() != null) {
                 decreaseScrollContexts = openScrollContexts::decrementAndGet;
                 if (openScrollContexts.incrementAndGet() > maxOpenScrollContext) {
                     throw new TooManyScrollContextsException(maxOpenScrollContext, MAX_OPEN_SCROLL_CONTEXT.getKey());
                 }
-            }
-            final ShardSearchContextId id = new ShardSearchContextId(sessionId, idGenerator.incrementAndGet());
-            if (request.scroll() != null) {
                 readerContext = new LegacyReaderContext(id, indexService, shard, reader, request, keepAliveInMillis);
-                if (request.scroll() != null) {
-                    readerContext.addOnClose(decreaseScrollContexts);
-                    decreaseScrollContexts = null;
-                }
+                readerContext.addOnClose(decreaseScrollContexts);
+                decreaseScrollContexts = null;
             } else {
                 readerContext = new ReaderContext(id, indexService, shard, reader, keepAliveInMillis, true);
             }
@@ -1011,16 +1006,9 @@ final ReaderContext createAndPutReaderContext(
             searchOperationListener.onNewReaderContext(finalReaderContext);
             if (finalReaderContext.scrollContext() != null) {
                 searchOperationListener.onNewScrollContext(finalReaderContext);
+                readerContext.addOnClose(() -> searchOperationListener.onFreeScrollContext(finalReaderContext));
             }
-            readerContext.addOnClose(() -> {
-                try {
-                    if (finalReaderContext.scrollContext() != null) {
-                        searchOperationListener.onFreeScrollContext(finalReaderContext);
-                    }
-                } finally {
-                    searchOperationListener.onFreeReaderContext(finalReaderContext);
-                }
-            });
+            readerContext.addOnClose(() -> searchOperationListener.onFreeReaderContext(finalReaderContext));
             putReaderContext(finalReaderContext);
             readerContext = null;
             return finalReaderContext;

server/src/main/java/org/elasticsearch/search/internal/ReaderContext.java

@@ -124,7 +124,7 @@ public Releasable markAsUsed(long keepAliveInMillis) {
         refCounted.incRef();
         tryUpdateKeepAlive(keepAliveInMillis);
         return Releasables.releaseOnce(() -> {
-            this.lastAccessTime.updateAndGet(curr -> Math.max(curr, nowInMillis()));
+            this.lastAccessTime.accumulateAndGet(nowInMillis(), Math::max);
             refCounted.decRef();
         });
     }