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https://issues.apache.org/jira/browse/PHOENIX-3326?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15520365#comment-15520365
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Samarth Jain commented on PHOENIX-3326:
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That should work, [~jamestaylor]. I am not too sure though if it really matters
whether name space mapping is enabled in this case. Also, is there an easy way
of marking certain words as reserved in the grammar. I essentially want to
block users from creating phoenix tables named SYSTEM.MUTEX. I can always add a
check in MetadataClient.createTable but was hoping there is probably a grammar
level check for the same.
> Restoring SYSTEM.CATALOG from snapshot causes clients to run into
> UpgradeInProgressException
> --------------------------------------------------------------------------------------------
>
> Key: PHOENIX-3326
> URL: https://issues.apache.org/jira/browse/PHOENIX-3326
> Project: Phoenix
> Issue Type: Bug
> Reporter: Samarth Jain
> Assignee: Samarth Jain
> Attachments: PHOENIX-3326_4.8-HBase-0.98.patch,
> PHOENIX-3326_4.8-HBase-0.98_v2.patch, PHOENIX-3326_wip.patch
>
>
> We create a snapshot of the SYSTEM.CATALOG table only after the client is
> able to successfully acquire a distributed mutex of sorts. This means the
> snapshot also ends up containing the row that serves as the mutex. Now when
> restoring the table from snapshot, this rows is still present which causes
> clients to throw UpgradeInProgress exception.
> I can think of a couple of ways to fix this:
> 1) Do the checkAndPut for the UPGRADE_MUTEX after creating the snapshot. I am
> not too sure though how about HBase handles concurrent snapshot requests. Do
> clients get an exception? Also we potentially could end up creating more
> snapshots than we really need to.
> 2) Do the checkAndPut for the UPGRADE_MUTEX in a different table (possibly
> SYSTEM.SEQUENCE). This way the restored snapshot won't have the row. We would
> need to delete the row from SYSTEM.SEQUENCE after the upgrade is done
> (successfully or unsuccessfully).
> [~jamestaylor] - WDYT?
> FYI, [~lhofhansl] - this is probably a blocker for 4.8.1
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