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https://issues.apache.org/jira/browse/HIVE-26145?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17534522#comment-17534522
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Janos Kovacs commented on HIVE-26145:
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OK, let's wait if there are other inputs.
On the side note: one of my ops mentioned, that configuring zero value for this
and expecting a continuous run is impossible if anyone knows it a little bit,
at least on a level to change the config as both the notification log cleaner
and the txn write notification cleaner run in the same call. That would 1)
hardly run within sub-sec or 2) would kill hive's performance as even with
hive.txn.readonly.enabled turned on, a generic use-case would generate
notifications and there would be continuous lock on backed db (although I have
another ticket to enhance index on these to make sure no table-scan lock these
in the RDBMS). If we add that tools actually depend on notification log's TTL,
it's more uncommon to have the cleaner running that frequently.
> Disable notification cleaner if interval is zero
> ------------------------------------------------
>
> Key: HIVE-26145
> URL: https://issues.apache.org/jira/browse/HIVE-26145
> Project: Hive
> Issue Type: Sub-task
> Components: Metastore
> Reporter: Janos Kovacs
> Assignee: Janos Kovacs
> Priority: Major
> Labels: pull-request-available
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> Many of the housekeeping/background tasks can be turned off in case of having
> multiple instances running parallel.
> Some are controlled via the housekeeping node configuration, others are not
> started if their frequency is set to zero.
> The DB-Notification cleaner unfortunately doesn't have this functionality
> which makes all instances to race for the lock on the backend HMS database.
> Goal is to add change to be able to turn cleaner off in case if there are
> multiple instances running (be able to bound it to the housekeeping
> instance).
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