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https://issues.apache.org/jira/browse/HBASE-7325?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13724423#comment-13724423
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Jean-Daniel Cryans commented on HBASE-7325:
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bq. We'd be polling the NN with 1 req/s/RegionServer.
FWIW when normally replicating we poll the NN way more than 1/sec. It'd be nice
if we didn't even have to do it as often. If at least we could finish reading
the current block without having to go back it'd be a huge win.
bq. Are we really concerned about a 10s latency after the cluster was idle for
a long time? There are many other reason why replication can get behind -
further behind than 10s.
I like it since you mitigate how long it can take to replicate an edit. Or for
users who setup replication and then try it out in the shell, hopefully they
wouldn't have to wait 10 seconds (I've seen this twice in the last two weeks).
> Replication reacts slowly on a lightly-loaded cluster
> -----------------------------------------------------
>
> Key: HBASE-7325
> URL: https://issues.apache.org/jira/browse/HBASE-7325
> Project: HBase
> Issue Type: Bug
> Components: Replication
> Reporter: Gabriel Reid
> Priority: Minor
> Attachments: HBASE-7325.patch, HBASE-7325.v2.patch
>
>
> ReplicationSource uses a backing-off algorithm to sleep for an increasing
> duration when an error is encountered in the replication run loop. However,
> this backing-off is also performed when there is nothing found to replicate
> in the HLog.
> Assuming default settings (1 second base retry sleep time, and maximum
> multiplier of 10), this means that replication takes up to 10 seconds to
> occur when there is a break of about 55 seconds without anything being
> written. As there is no error condition, and there is apparently no
> substantial load on the regionserver in this situation, it would probably
> make more sense to not back off in non-error situations.
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