From: Tom Lane <tgl@sss.pgh.pa.us>
To: Rick Otten <rottenwindfish@gmail.com>
Cc: pgsql-performance@lists.postgresql.org, Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>
Subject: Re: dsa_allocate() faliure
Date: Mon, 29 Jan 2018 11:37:09 -0500
Message-ID: <4763.1517243829@sss.pgh.pa.us> (raw)
In-Reply-To: <CAMAYy4+w3NTBM5JLWFi8twhWK4=k_5L4nV5+bYDSPu8r4b97Zg@mail.gmail.com>
References: <CAMAYy4+w3NTBM5JLWFi8twhWK4=k_5L4nV5+bYDSPu8r4b97Zg@mail.gmail.com>
Rick Otten <rottenwindfish@gmail.com> writes:
> I'm wondering if there is anything I can tune in my PG 10.1 database to
> avoid these errors:
> $ psql -f failing_query.sql
> psql:failing_query.sql:46: ERROR: dsa_allocate could not find 7 free pages
> CONTEXT: parallel worker
Hmm. There's only one place in the source code that emits that message
text:
/*
* Ask the free page manager for a run of pages. This should always
* succeed, since both get_best_segment and make_new_segment should
* only return a non-NULL pointer if it actually contains enough
* contiguous freespace. If it does fail, something in our backend
* private state is out of whack, so use FATAL to kill the process.
*/
if (!FreePageManagerGet(segment_map->fpm, npages, &first_page))
elog(FATAL,
"dsa_allocate could not find %zu free pages", npages);
Now maybe that comment is being unreasonably optimistic, but it sure
appears that this is supposed to be a can't-happen case, in which case
you've found a bug.
cc'ing the DSA authors for comment.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, rottenwindfish@gmail.com, robertmhaas@gmail.com, thomas.munro@enterprisedb.com
Subject: Re: dsa_allocate() faliure
In-Reply-To: <4763.1517243829@sss.pgh.pa.us>
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