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https://issues.apache.org/jira/browse/HBASE-22289?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16823507#comment-16823507
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Sergey Shelukhin commented on HBASE-22289:
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Actually nm, ZK error was a red herring (although it could still happen if
other ZK update fails; in this case it was actually a take-ownership that
failed, and it succeeded on retry).
I see that RS logged handler.WALSplitterHandler: task execution preempted for
this task.
That led me to this helpful TODO:
{noformat}
// TODO have to correctly figure out when log splitting has been
// interrupted or has encountered a transient error and when it has
// encountered a bad non-retry-able persistent error.
if (!WALSplitter.splitLogFile(walDir, fs.getFileStatus(new Path(walDir,
name)), fs, conf, p,
sequenceIdChecker, splitLogWorkerCoordination, factory)) {
return Status.PREEMPTED;
}
{noformat}
When task is preempted RS in fact never updates task for the master. I'm not
sure what the logic is behind that, what is master supposed to gain from not
having the updated information.
> WAL-based log splitting resubmit threshold results in a task being stuck
> forever
> --------------------------------------------------------------------------------
>
> Key: HBASE-22289
> URL: https://issues.apache.org/jira/browse/HBASE-22289
> Project: HBase
> Issue Type: Bug
> Reporter: Sergey Shelukhin
> Priority: Major
>
> Not sure if this is handled better in procedure based WAL splitting; in any
> case it affects versions before that.
> The problem is not in ZK as such but in internal state tracking in master, it
> seems.
> Master:
> {noformat}
> 2019-04-21 01:49:49,584 INFO
> [master/<master>:17000.splitLogManager..Chore.1]
> coordination.SplitLogManagerCoordination: Resubmitting task
> <path>.1555831286638
> {noformat}
> worker-rs, split fails
> {noformat}
> ....
> 2019-04-21 02:05:31,774 INFO
> [RS_LOG_REPLAY_OPS-regionserver/<worker-rs>:17020-1] wal.WALSplitter:
> Processed 24 edits across 2 regions; edits skipped=457; log
> file=<path>.1555831286638, length=2156363702, corrupted=false, progress
> failed=true
> {noformat}
> Master (not sure about the delay of the acquired-message; at any rate it
> seems to detect the failure fine from this server)
> {noformat}
> 2019-04-21 02:11:14,928 INFO [main-EventThread]
> coordination.SplitLogManagerCoordination: Task <path>.1555831286638 acquired
> by <worker-rs>,17020,1555539815097
> 2019-04-21 02:19:41,264 INFO
> [master/<master>:17000.splitLogManager..Chore.1]
> coordination.SplitLogManagerCoordination: Skipping resubmissions of task
> <path>.1555831286638 because threshold 3 reached
> {noformat}
> After that this task is stuck in the limbo forever with the old worker, and
> never resubmitted.
> RS never logs anything else for this task.
> Killing the RS on the worker unblocked the task and some other server did the
> split very quickly, so seems like master doesn't clear the worker name in its
> internal state when hitting the threshold... master never restarted so
> restarting the master might have also cleared it.
> This is extracted from splitlogmanager log messages, note the times.
> {noformat}
> 2019-04-21 02:2 1555831286638=last_update = 1555837874928 last_version = 11
> cur_worker_name = <worker-rs>,17020,1555539815097 status = in_progress
> incarnation = 3 resubmits = 3 batch = installed = 24 done = 3 error = 20,
> ....
> 2019-04-22 11:1 1555831286638=last_update = 1555837874928 last_version = 11
> cur_worker_name = <worker-rs>,17020,1555539815097 status = in_progress
> incarnation = 3 resubmits = 3 batch = installed = 24 done = 3 error = 20}
> {noformat}
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