Re: Parallel Seq Scan - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: Parallel Seq Scan
Date
Msg-id CAA4eK1LZMJNMkR3gP0g0Mo1K4iGj5z8s-oOb4WT1dd=JgQjNxQ@mail.gmail.com
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In response to Re: Parallel Seq Scan  (Haribabu Kommi <kommi.haribabu@gmail.com>)
Responses Re: Parallel Seq Scan
Re: Parallel Seq Scan
List pgsql-hackers
On Tue, Mar 10, 2015 at 6:50 AM, Haribabu Kommi <kommi.haribabu@gmail.com> wrote:
>
> On Tue, Mar 10, 2015 at 1:38 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
> > Assuming previous patch is in right direction, I have enabled
> > join support for the patch and done some minor cleanup of
> > patch which leads to attached new version.
>
> Is this patch handles the cases where the re-scan starts without
> finishing the earlier scan?
>

Do you mean to say cases like ANTI, SEMI Join (in nodeNestLoop.c)
where we scan the next outer tuple and rescan inner table without
completing the previous scan of inner table?

I have currently modelled it based on existing rescan for seqscan
(ExecReScanSeqScan()) which means it will begin the scan again.
Basically if the workers are already started/initialized by previous
scan, then re-initialize them (refer function ExecReScanFunnel() in
patch).

Can you elaborate more if you think current handling is not sufficient
for any case?

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

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