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https://issues.apache.org/jira/browse/HBASE-8310?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13663645#comment-13663645
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Matteo Bertozzi commented on HBASE-8310:
----------------------------------------
-1 on the patch
{quote}We are more relying on the table lock at the moment to prevent
concurrent snapshot of the same table.{quote}
No. The table lock is not involved with the "Reject snapshot" exception.
The synchronized block cover the fact that a single snapshot at the time can be
enqueued, and the snapshotHandler is checked before performing a
snapshotTable() operation. isSnapshotInProgress() or isRestoreInProgress() are
the ones that throws the "rejecting snapshot exception" not the table lock.
Take a look a SnapshotManager.prepareToTakeSnapshot() to see where the
exception is thrown.
> HBase snapshot timeout default values and TableLockManger timeout
> -----------------------------------------------------------------
>
> Key: HBASE-8310
> URL: https://issues.apache.org/jira/browse/HBASE-8310
> Project: HBase
> Issue Type: Bug
> Components: snapshots
> Affects Versions: 0.95.0
> Reporter: Jerry He
> Assignee: Jerry He
> Priority: Minor
> Fix For: 0.98.0, 0.95.2, 0.94.9
>
> Attachments: trunk.patch
>
>
> There are a few timeout values and defaults being used by HBase snapshot.
> DEFAULT_MAX_WAIT_TIME (60000 milli sec, 1 min) for client response
> TIMEOUT_MILLIS_DEFAULT (60000 milli sec, 1 min) for Procedure timeout
> SNAPSHOT_TIMEOUT_MILLIS_DEFAULT (60000 milli sec, 1 min) for region server
> subprocedure
> There is also other timeout involved, for example,
> DEFAULT_TABLE_WRITE_LOCK_TIMEOUT_MS (10 mins) for
> TakeSnapshotHandler#prepare()
> We could have this case:
> The user issues a sync snapshot request, waits for 1 min, and gets an
> exception.
> In the meantime the snapshot handler is blocked on the table lock, and the
> snapshot may continue to finish after 10 mins.
> But the user will probably re-issue the snapshot request during the 10 mins.
> This is a little confusing and messy when this happens.
> To be more reasonable, we should either increase the DEFAULT_MAX_WAIT_TIME or
> decrease the table lock waiting time.
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