2pc leaks fds - Mailing list pgsql-hackers

From Andres Freund
Subject 2pc leaks fds
Date
Msg-id 20200406025651.fpzdb5yyb7qyhqko@alap3.anarazel.de
Whole thread Raw
Responses Re: 2pc leaks fds  (Michael Paquier <michael@paquier.xyz>)
List pgsql-hackers
Hi,

Using 2PC with master very quickly leads to:

2020-04-05 19:42:18.368 PDT [2298126][5/2009:0] LOG:  out of file descriptors: Too many open files; release and retry
2020-04-05 19:42:18.368 PDT [2298126][5/2009:0] STATEMENT:  COMMIT PREPARED 'ptx_2';

This started with:

commit 0dc8ead46363fec6f621a12c7e1f889ba73b55a9 (HEAD -> master)
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date:   2019-11-25 15:04:54 -0300

    Refactor WAL file-reading code into WALRead()


I found this while trying to benchmark the effect of my snapshot changes
on 2pc. I just used the attached pgbench file.

andres@awork3:~/build/postgres/dev-assert/vpath$ pgbench -n -s 500 -c 4 -j 4 -T 100000 -P1 -f
~/tmp/pgbench-write-2pc.sql
progress: 1.0 s, 3723.8 tps, lat 1.068 ms stddev 0.305
client 2 script 0 aborted in command 8 query 0: ERROR:  could not seek to end of file "base/14036/16396": Too many open
files
client 1 script 0 aborted in command 8 query 0: ERROR:  could not seek to end of file "base/14036/16396": Too many open
files
client 3 script 0 aborted in command 8 query 0: ERROR:  could not seek to end of file "base/14036/16396": Too many open
files
client 0 script 0 aborted in command 8 query 0: ERROR:  could not seek to end of file "base/14036/16396": Too many open
files
transaction type: /home/andres/tmp/pgbench-write-2pc.sql

I've not yet reviewed the change sufficiently to pinpoint the issue.


It's a bit sad that nobody has hit this in the last few months :(.

Greetings,

Andres Freund

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