From: | Adrien Nayrat <adrien(dot)nayrat(at)anayrat(dot)info> |
---|---|
To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
Cc: | PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Explain buffers wrong counter with parallel plans |
Date: | 2018-04-30 14:35:07 |
Message-ID: | 4720544a-9770-952e-c157-2c89845f56f3@anayrat.info |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 04/29/2018 05:10 PM, Amit Kapila wrote:
> Yeah, it would have been convenient, if Gather and Finalize Aggregate
> displays that way as it would have been easier for users to
> understand. However, as of now, the aggregated stats for parallel
> workers and leader are displayed at parallel/partial nodes as is
> displayed in the plan. So according to me, what you are seeing is
> okay, it is only slightly tricky to understand it.
>
[...]
>
>> I played with git bisect and I found this commit :
>>
>> commit 01edb5c7fc3bcf6aea15f2b3be36189b52ad9d1a
>> Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
>> Date: Fri Sep 1 17:38:54 2017 -0400
>>
> I think you were seeing different results before this commit because
> before that we were shutting down workers as soon as parallel workers
> are done and the buffer_usage stats were accumulated and were being
> used for upper nodes. According to me behavior after the commit is
> consistent, for example, I think if you check the case of GatherMerge
> before this commit, you will still get the stats in the way it is
> after commit.
I understand. Maybe, this change should be mentioned in releases notes and/or
documentation?
Thanks,
From | Date | Subject | |
---|---|---|---|
Next Message | Michael Meskes | 2018-04-30 15:23:43 | Re: Intermittent ECPG test failures on Windows buildfarm machines |
Previous Message | Adrien Nayrat | 2018-04-30 14:32:26 | Re: Explain buffers wrong counter with parallel plans |