| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Jinho Jung <jinhojun(at)usc(dot)edu> |
| Cc: | Peter Geoghegan <pg(at)bowt(dot)ie>, PostgreSQL mailing lists <pgsql-bugs(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Parallel query execution introduces performance regressions |
| Date: | 2019-04-01 19:13:04 |
| Message-ID: | 20190401191304.x6ieib4bj73hywa6@alap3.anarazel.de |
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| Thread: | |
| Lists: | pgsql-bugs |
Hi,
Please don't top-quote on postgres mailing lists.
On 2019-04-01 15:08:59 -0400, Jinho Jung wrote:
> Sorry for the duplicated thread here and thanks for the reply.
>
> I have another question regarding parallel execution. We noticed that
> PostgreSQL sometimes launches only one worker. Is that also an intended
> behavior?
Note that even a single worker is a form of parallelism - the "main"
backend also participates in query execution. So yes, that can be a
reasonable behaviour. Also, it might be that query was just finished
faster than a worker was able to launch.
- Andres
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