Re: Parallel execution and prepared statements

From: Tobias Bussmann <t(dot)bussmann(at)gmx(dot)net>
To: "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Cc: Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>
Subject: Re: Parallel execution and prepared statements
Date: 2016-11-15 20:57:09
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As the patch in [1] targeting the execution of the plan in ExecutePlan depending on the destination was declined, I hacked around a bit to find another way to use parallel mode with SQL prepared statements while disabling the parallel execution in case of an non read-only execution. For this I used the already present test for an existing intoClause in ExecuteQuery to set the parallelModeNeeded flag of the prepared statement. This results in a non parallel execution of the parallel plan, as we see with a non-zero fetch count used with the extended query protocol. Despite this patch seem to work in my tests, I'm by no means confident this being a proper way of handling the situation in question.



Attachment Content-Type Size
prepared_stmt_execute_parallel_query.patch application/octet-stream 1.7 KB
unknown_filename text/plain 3 bytes

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