Rajesh Balamohan created HDDS-2382:
--------------------------------------

             Summary: Consider reducing number of file::exists() calls during 
write operation
                 Key: HDDS-2382
                 URL: https://issues.apache.org/jira/browse/HDDS-2382
             Project: Hadoop Distributed Data Store
          Issue Type: Bug
          Components: Ozone Datanode
            Reporter: Rajesh Balamohan


When writing 100-200 MB files with multiple threads, observed lots of 
{{[file::exists(])}} checks.

For every 16 MB chunk, it ends up checking whether {{chunksLoc}} directory 
exists or not. (ref: 
[https://github.com/apache/hadoop-ozone/blob/master/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/keyvalue/helpers/ChunkUtils.java#L239])

Also, this check ({{ChunkUtils.getChunkFile}}) happens from 2 places.

1.org.apache.hadoop.ozone.container.common.transport.server.ratis.ContainerStateMachine.lambda$handleWriteChunk

2.org.apache.hadoop.ozone.container.common.transport.server.ratis.ContainerStateMachine.lambda$applyTransaction

Note that these are folders and not actual chunk filenames. It would be helpful 
to reduce this check, if we track create/delete of these folders.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org

Reply via email to