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https://issues.apache.org/jira/browse/HBASE-7847?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13962599#comment-13962599
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Rakesh R commented on HBASE-7847:
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Thanks [~stack] for the reply. Kindly see my thoughts :
bq. we should require a zk 3.4.x for hbase?
Yes
bq. The hang will happen on any zk before 3.4.6? When was multi added? Do you
know?
Multi feature is added by ZOOKEEPER-965 and 3.4.0 onwards. So for multi
support, atleast we need 3.4.x version and we can recommended to set multi if
zk version is 3.4.x or higher version. AFAIK, client would get hang if exec
multi before 3.4.x. Presently this is a limitation in zk older versions.
bq. Is it possible to ask zk what version it is? It was not possible in the
past but may be fixed in 3.4.6? If so, that'd be cool. Then we could ask and
then do multi going forward (Though if I remember, the issue here is that only
one member of the ensemble, the one we are talking too, could report itself
3.4.6 but all others could be at an earlier version).
We have a JIRA ZOOKEEPER-1381 to discuss the feasibility. But like you
mentioned, if the connected server(follower/observer) is of higher version and
the Leader is with lower version, I also feel it may not work out as per the
client's expectations.
Also, I could see there are similar discussion happened earlier in HBASE-6058.
Please follow link : [ZK multi api usage
HBASE|https://issues.apache.org/jira/i#browse/HBASE-6058?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel&issueKey=HBASE-6058&serverRenderedViewIssue=true&focusedCommentId=13398282]
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If you agree with all these, I would be happy to prepare a new patch by fixing
your comments (except the execution of multi irerspective of zk versions)
Thanks,
Rakesh R
> Use zookeeper multi to clear znodes
> -----------------------------------
>
> Key: HBASE-7847
> URL: https://issues.apache.org/jira/browse/HBASE-7847
> Project: HBase
> Issue Type: Sub-task
> Reporter: Ted Yu
> Assignee: Rakesh R
> Attachments: 7847-v1.txt, 7847_v6.patch, 7847_v6.patch,
> HBASE-7847.patch, HBASE-7847.patch, HBASE-7847.patch, HBASE-7847_v4.patch,
> HBASE-7847_v5.patch, HBASE-7847_v6.patch
>
>
> In ZKProcedureUtil, clearChildZNodes() and clearZNodes(String procedureName)
> should utilize zookeeper multi so that they're atomic
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