bug#43850: closed (cuirass: inconsistent SQL queries execution time.)

[GNU bug Tracking System]

Your message dated Thu, 25 Mar 2021 13:46:25 +0100
with message-id <87mtur5rku.fsf@gnu.org>
and subject line Re: bug#43850: cuirass: inconsistent SQL queries execution 
time.
has caused the debbugs.gnu.org bug report #43850,
regarding cuirass: inconsistent SQL queries execution time.
to be marked as done.

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-- 
43850: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=43850
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> --- Begin Message ---
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> Subject: 
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> cuirass: inconsistent SQL queries execution time.
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> Date: 
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> Wed, 07 Oct 2020 18:04:52 +0200
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> User-agent: 
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> Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
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> Hello,
>
> Over the last few weeks I made sure that all Cuirass SQL queries were
> using indexes. As the "Builds" and "Outputs" tables can be really large,
> having queries covered by indexes is imperative for consistent queries
> duration.
>
> However, I observed that some queries have inconsistent duration.
>
> --8<---------------cut here---------------start------------->8---
> 2020-10-07T17:59:09 Database worker unresponsive for 5 seconds 
> (db-get-builds-max).
> 2020-10-07T17:59:13 GET /build/3183151/details
> 2020-10-07T17:59:13 GET /eval/92
> 2020-10-07T17:59:14 builds request took 3.66e-4 seconds
> 2020-10-07T17:59:14 Database worker unresponsive for 5 seconds 
> (db-get-builds-max).
> 2020-10-07T17:59:15 GET /eval/13234
> 2020-10-07T17:59:16 GET /build/3146487/details
> 2020-10-07T17:59:19 Database worker unresponsive for 5 seconds 
> (db-get-builds-max).
> --8<---------------cut here---------------end--------------->8---
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> "db-get-builds-max" query has the following query plan:
>
> --8<---------------cut here---------------start------------->8---
> QUERY PLAN
> |--SEARCH TABLE Builds USING INDEX Builds_stoptime_id (stoptime=?)
> `--SCALAR SUBQUERY 1
>    `--SEARCH TABLE Builds USING INDEX Builds_evaluation_index (evaluation=?)
> --8<---------------cut here---------------end--------------->8---
>
> so it should always reasonably fast. The log seem to indicate that the
> worker running one of those queries is busy for more than 10 seconds
> here. My understanding of SQLite WAL mode is that writers should not
> block readers. So I don't get why this query can be intermittently so
> slow.
>
> Thanks,
>
> Mathieu
> -- 
> https://othacehe.org
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#43850: cuirass: inconsistent SQL queries execution time.
>
>
>
>
> Date: 
>
> Thu, 25 Mar 2021 13:46:25 +0100
>
>
>
>
> User-agent: 
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> Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
>
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>
> Closing as this is not any issue anymore since the switch to PostgreSQL.
>
> Mathieu
>
>
> --- End Message ---