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help / color / mirror / Atom feedFrom: Adrian Klaver <[email protected]>
To: Colin 't Hart <[email protected]>
Cc: PostgreSQL General <[email protected]>
Subject: Re: pgBadger and postgres_fdw
Date: Wed, 21 Jan 2026 08:59:17 -0800
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAMon-aT92+JQVTD54iwEmPpkFRDHDnhOzZGHMG6GoH_8Qh_EDg@mail.gmail.com>
References: <CAMon-aR8f3zi1Wytg-TCrbLa=sAooi4kTzbjukcvdt8G4mycbw@mail.gmail.com>
<[email protected]>
<CAMon-aT92+JQVTD54iwEmPpkFRDHDnhOzZGHMG6GoH_8Qh_EDg@mail.gmail.com>
On 1/21/26 08:12, Colin 't Hart wrote:
> 6. The 19 slowest queries in a 4 hour period are between 2 and 37
> minutes, with an average of over 10 minutes; they are all `fetch 100
> from c2`.
>
> The slowness itself isn't my question here; it was caused by having too
> few cores in the new environment, while the application was still
> assuming the higher core count and generating too many concurrent processes.
>
> My question is how to identify which connections / queries from
> postgres_fdw are generating the `fetch 100 from c2` queries, which, in
> turn, may quite possibly lead to a feature request for having these
> named uniquely.
My guess not.
See:
https://github.com/postgres/postgres/blob/master/contrib/postgres_fdw/postgres_fdw.c
Starting at line ~5212
fetch_size = 100;
and ending at line ~5234
/* Construct command to fetch rows from remote. */
snprintf(fetch_sql, sizeof(fetch_sql), "FETCH %d FROM c%u",
fetch_size, cursor_number);
So c2 is a cursor number.
>
> Thanks,
>
> Colin
>
--
Adrian Klaver
[email protected]
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