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https://issues.apache.org/jira/browse/HBASE-10001?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13827933#comment-13827933
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Nicolas Liochon edited comment on HBASE-10001 at 11/20/13 6:25 PM:
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There is a bug linked to this:
in HRegion#doMiniBatchMutation:
we start with:
{code}boolean walSyncSuccessful = false;{code}
if the preBatch hook call byPass, we then return immediately, because of this:
{code}if (coprocessorHost.preBatchMutate(miniBatchOp)) return 0L;{code}
then the finally clause is executed with walSyncSuccessful set to false, and
then we try to rollback the memstore.
{code}
if (!walSyncSuccessful) {
rollbackMemstore(batchOp, familyMaps, firstIndex, lastIndexExclusive);
}
{code}
In my load test, we're spending 15% of our time in the rollback.
I can fix this in the coprocessor (by not setting bypass), but I think we
should set the value of walSyncSuccessful later, just before we try to write
something in the memstore:
Any opinion? I can do the fix in HRegion#doMiniBatchMutation or in the
coprocessor.
was (Author: nkeywal):
There is a bug linked to this:
in HRegion#doMiniBatchMutation:
we start with:
??boolean walSyncSuccessful = false;??
if the preBatch hook call byPass, we then return immediately, because of this:
?? if (coprocessorHost.preBatchMutate(miniBatchOp)) return 0L;??
then the finally clause is executed with ??walSyncSuccessful?? set to false,
and then we try to rollback the memstore.
In my load test, we're spending 15% of our time in the rollback.
I can fix this in the coprocessor (by not setting bypass), but I think we
should set the value of walSyncSuccessful later, just before we try to write
something in the memstore.
Any opinion? I can do the fix in HRegion#doMiniBatchMutation or in the
coprocessor.
> Add a coprocessor to help testing the performances without taking into
> account the i/o
> --------------------------------------------------------------------------------------
>
> Key: HBASE-10001
> URL: https://issues.apache.org/jira/browse/HBASE-10001
> Project: HBase
> Issue Type: Improvement
> Components: test
> Affects Versions: 0.98.0, 0.96.0, 0.94.13
> Reporter: Nicolas Liochon
> Assignee: Nicolas Liochon
> Priority: Minor
> Fix For: 0.98.0, 0.96.1, 0.94.15
>
> Attachments: 10001.v1.patch, 10001.v2.patch
>
>
> We have a mockup to test only the client. If we want to include the network,
> without beeing limited by the i/o, we don't have much tools.
> This coprocessor helps to test this.
> I put it in the main code as to make it usable without adding a jar...
> I don't think it's possible avoid the WAL writes in the coprocessors. It
> would be great to have it to simplify the test with any kind of client (i.e.
> w/o changing the durability).
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