[jira] [Commented] (HBASE-6058) Use ZK 3.4 API 'multi' in bulk assignment

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

    [ https://issues.apache.org/jira/browse/HBASE-6058?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13508963#comment-13508963 ] 

nkeywal commented on HBASE-6058:
--------------------------------

I've tested ZK#multi on assignment in master: no real improvement actually because we’re actually spending our time in the region server. We lower the load on ZK, but it would be visible only on a large cluster. As using multi would require to use ZK 3.4, it’s not compelling enough to do the move.

Note that's because:
- the master part I've changed is doing asynchronous writes, faster than synchronous writes
- ZooKeeper does nothing else. On a large cluster, it would be more interesting.
- there is no real bulk assign in the region server (i.e. a regionserver receives 20 regions simultaneously). So we don't need multi there today.

                
> Use ZK 3.4 API 'multi' in bulk assignment
> -----------------------------------------
>
>                 Key: HBASE-6058
>                 URL: https://issues.apache.org/jira/browse/HBASE-6058
>             Project: HBase
>          Issue Type: Improvement
>          Components: master, Zookeeper
>    Affects Versions: 0.96.0
>            Reporter: nkeywal
>            Assignee: nkeywal
>            Priority: Minor
>
> We use async API today. This is already much much faster than the sync API. Still, it makes sense to use the 'multi' function: this will decrease the network & zookeeper load at startup/rolling restart.
> On a 500 nodes cluster, we see 3 that 3 seconds are spent on updating ZK per bulk assignment. This should cut it in half (+ the benefits on the network/zk load).

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira