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https://issues.apache.org/jira/browse/PHOENIX-1751?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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James Taylor updated PHOENIX-1751:
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Attachment: PHOENIX-1751_v4.patch
Basically a version of [~lhofhansl]'s rebased patch, but with a simple test
that simulates the preScannerNext taking longer than the RPC timeout. The test
passes, but if I put the delay in the preScannerOpen or postScannerOpen, it
fails.
Please review [~samarthjain]. This essentially works around the issue with the
ClientScanner being locked out from renewing the lease when the initial next()
takes a long time.
Let us know if you have any input too, [~lhofhansl].
> Perform aggregations, sorting, etc, in the preScannerNext instead of
> postScannerOpen
> ------------------------------------------------------------------------------------
>
> Key: PHOENIX-1751
> URL: https://issues.apache.org/jira/browse/PHOENIX-1751
> Project: Phoenix
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Attachments: 1751-WIP-v2.txt, 1751-WIP-v2b.patch, 1751-WIP.txt,
> PHOENIX-1751-v2c.patch, PHOENIX-1751.patch, PHOENIX-1751_v3.patch,
> PHOENIX-1751_v4.patch
>
>
> HBase retains a lease for every scanner. Then lease expires the scan will no
> longer (be allowed to) work. The leases guard against the client going away,
> and allow cleaning up resources if that happens.
> At various points HBase "suspends" the lease while the region server are
> working on behalf of this scanner, so that the lease won't expire even though
> the server is working on it.
> HBase does that during the scanning process. Crucially it suspends the leaser
> after the scanner is opened, before next() is issued on it.
> The outcome of all this is that Phoenix executes aggregates, sorts, etc, with
> the lease in place, and hence if these take a bit the lease can expire even
> though the server was working on it.
> Phoenix should do this work in preScannerNext, being careful that the
> precalculation is only performed once.
> I'll attach a sample patch soon.
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