From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [COMMITTERS] pgsql: Simplify plpgsql's check for simple expressions. |
Date: | 2017-08-16 16:49:32 |
Message-ID: | 28589.1502902172@sss.pgh.pa.us |
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Lists: | pgsql-committers pgsql-hackers |
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Wed, Aug 16, 2017 at 11:56 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> I can get on board with that statement. Can you draft a better wording?
> Here is an attempt. Feel free to edit.
I think s/plan/query/ in the last bit would be better. Perhaps
+ * However, if force_parallel_mode = on or force_parallel_mode = regress,
+ * then we impose parallel mode whenever it's safe to do so, even if the
+ * final plan doesn't use parallelism. It's not safe to do so if the query
+ * contains anything parallel-unsafe; parallelModeOK will be false in that
+ * case. Otherwise, everything in the query is either parallel-safe or
+ * parallel-restricted, and in either case it should be OK to impose
+ * parallel-mode restrictions. If that ends up breaking something, then
+ * either some function the user included in the query is incorrectly
+ * labelled as parallel-safe or parallel-restricted when in reality it's
+ * parallel-unsafe, or else the query planner itself has a bug.
*/
regards, tom lane
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