[jira] [Commented] (CASSANDRA-12864) "commitlog_sync_batch_window_in_ms" parameter is not working correctly in 2.1, 2.2 and 3.9

["Hiroyuki Yamada (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-12864?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15624234#comment-15624234 ] 

Hiroyuki Yamada commented on CASSANDRA-12864:
---------------------------------------------

OK, thank you for pointing out, Benjamin.
In that case, the documents should be described more correctly.
They say it waits commitlog_sync_batch_window_in_ms .

> To Apache Cassandra Community
http://cassandra.apache.org/doc/latest/configuration/cassandra_config_file.html?highlight=sync#commitlog-sync

> To Datastax
http://docs.datastax.com/en/cassandra/2.1/cassandra/configuration/configCassandra_yaml_r.html#reference_ds_qfg_n1r_1k__commitlog_sync
http://docs.datastax.com/en/cassandra/3.0/cassandra/configuration/configCassandra_yaml.html#configCassandra_yaml__commitlog_sync

Also, if it is the expected behavior, I think it's kind of missing the points of group commit because it can't really control the window size and almost all of the mutations are committed right after they are issued.
So it can't control the balance between latency and throughput.



> "commitlog_sync_batch_window_in_ms" parameter is not working correctly in 2.1, 2.2 and 3.9
> ------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-12864
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-12864
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Hiroyuki Yamada
>
> "commitlog_sync_batch_window_in_ms" doesn't seem to be working at least in the latest versions in 2.1.16, 2.2.8 and 3.9.
> Here is the way to reproduce the bug.
> 1.  set the following parameters in cassandra.yaml
> * commitlog_sync: batch
> * commitlog_sync_batch_window_in_ms: 10000 (10s)
> 2. issue an insert from cqlsh
> 3. it immediately returns instead of waiting for 10 seconds.
> Please refer to the communication in the mailing list.
> http://www.mail-archive.com/user@cassandra.apache.org/msg49642.html



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