Guoqiang Jiang created LUCENE-7919:
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Summary: excessive use of notifyAll
Key: LUCENE-7919
URL: https://issues.apache.org/jira/browse/LUCENE-7919
Project: Lucene - Core
Issue Type: Bug
Components: core/index
Affects Versions: 6.6
Reporter: Guoqiang Jiang
I am using Elasticsearch and have a write heavy scene. When tuning with jstack,
I found a significant proportion of thread stacks similar to the followings:
{code:java}
"elasticsearch[test][bulk][T#23]" #126 daemon prio=5 os_prio=0
tid=0x00007f68f8040000 nid=0x6b1 runnable [0x00007f6918ce9000]
java.lang.Thread.State: RUNNABLE
at java.lang.Object.notifyAll(Native Method)
at
org.apache.lucene.index.DocumentsWriterPerThreadPool.release(DocumentsWriterPerThreadPool.java:213)
- locked <0x00000000ea02b6d0> (a
org.apache.lucene.index.DocumentsWriterPerThreadPool)
at
org.apache.lucene.index.DocumentsWriter.updateDocument(DocumentsWriter.java:496)
at
org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:1571)
at
org.apache.lucene.index.IndexWriter.addDocument(IndexWriter.java:1316)
at
org.elasticsearch.index.engine.InternalEngine.index(InternalEngine.java:663)
at
org.elasticsearch.index.engine.InternalEngine.indexIntoLucene(InternalEngine.java:607)
at
org.elasticsearch.index.engine.InternalEngine.index(InternalEngine.java:505)
at org.elasticsearch.index.shard.IndexShard.index(IndexShard.java:556)
at org.elasticsearch.index.shard.IndexShard.index(IndexShard.java:545)
at
org.elasticsearch.action.bulk.TransportShardBulkAction.executeIndexRequestOnPrimary(TransportShardBulkAction.java:484)
at
org.elasticsearch.action.bulk.TransportShardBulkAction.executeBulkItemRequest(TransportShardBulkAction.java:143)
at
org.elasticsearch.action.bulk.TransportShardBulkAction.shardOperationOnPrimary(TransportShardBulkAction.java:113)
at
org.elasticsearch.action.bulk.TransportShardBulkAction.shardOperationOnPrimary(TransportShardBulkAction.java:69)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$PrimaryShardReference.perform(TransportReplicationAction.java:939)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$PrimaryShardReference.perform(TransportReplicationAction.java:908)
at
org.elasticsearch.action.support.replication.ReplicationOperation.execute(ReplicationOperation.java:113)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$AsyncPrimaryAction.onResponse(TransportReplicationAction.java:322)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$AsyncPrimaryAction.onResponse(TransportReplicationAction.java:264)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$1.onResponse(TransportReplicationAction.java:888)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$1.onResponse(TransportReplicationAction.java:885)
at
org.elasticsearch.index.shard.IndexShardOperationsLock.acquire(IndexShardOperationsLock.java:147)
at
org.elasticsearch.index.shard.IndexShard.acquirePrimaryOperationLock(IndexShard.java:1657)
at
org.elasticsearch.action.support.replication.TransportReplicationAction.acquirePrimaryShardReference(TransportReplicationAction.java:897)
at
org.elasticsearch.action.support.replication.TransportReplicationAction.access$400(TransportReplicationAction.java:93)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$AsyncPrimaryAction.doRun(TransportReplicationAction.java:281)
at
org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$PrimaryOperationTransportHandler.messageReceived(TransportReplicationAction.java:260)
at
org.elasticsearch.action.support.replication.TransportReplicationAction$PrimaryOperationTransportHandler.messageReceived(TransportReplicationAction.java:252)
at
org.elasticsearch.transport.RequestHandlerRegistry.processMessageReceived(RequestHandlerRegistry.java:69)
at
org.elasticsearch.transport.TransportService$7.doRun(TransportService.java:644)
at
org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:638)
at
org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
{code}
After reading the code related with DocumentsWriterPerThreadPool, I think the
notifyAll is useless. This is a relatively expensive operation, and should be
avoided if possible.
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