autovacuum locking question
Mike Schanne <[email protected]> Thu, 5 Dec 2019 17:46:19 +0000
| Newsgroups | gmane.comp.db.postgresql.performance |
|---|---|
| Message-ID | <[email protected]> |
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Hi,
I am investigating a performance problem in our application and am seeing s=
omething unexpected in the postgres logs regarding the autovacuum.
2019-12-01 13:05:39.029 UTC,"wb","postgres",6966,"127.0.0.1:53976",5ddbd990=
.1b36,17099,"INSERT waiting",2019-11-25 13:39:28 UTC,12/1884256,12615023,LO=
G,00000,"process 6966 still waiting for RowExclusiveLock on relation 32938 =
of database 32768 after 1000.085 ms","Process holding the lock: 6045. Wait =
queue: 6966.",,,,,"INSERT INTO myschema.mytable (...) VALUES (...) RETURNIN=
G process.mytable.mytable_id",13,,""
2019-12-01 13:05:39.458 UTC,,,6045,,5de3b800.179d,1,,2019-12-01 12:54:24 UT=
C,10/417900,0,ERROR,57014,"canceling autovacuum task",,,,,"automatic vacuum=
of table ""postgres.myschema.mytable""",,,,""
My understanding from reading the documentation was that a vacuum can run c=
oncurrently with table inserts/updates, but from reading the logs it appear=
s they are conflicting over a row lock. This particular table gets very fr=
equent inserts/updates (10-100 inserts / sec) so I am concerned that if the=
autovacuum is constantly canceled, then the table never gets cleaned and i=
ts performance will continue to degrade over time. Is it expected for the =
vacuum to be canceled by an insert in this way?
We are using postgres 9.6.10.
Thanks,
Mike
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<p class=3D"MsoNormal">Hi,<o:p></o:p></p>
<p class=3D"MsoNormal">I am investigating a performance problem in our appl=
ication and am seeing something unexpected in the postgres logs regarding t=
he autovacuum.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">2019-12-01 13:05:39.029 UTC,"wb","pos=
tgres",6966,"127.0.0.1:53976",5ddbd990.1b36,17099,"INSE=
RT waiting",2019-11-25 13:39:28 UTC,12/1884256,12615023,LOG,00000,&quo=
t;process 6966 still waiting for RowExclusiveLock on relation 32938 of data=
base
32768 after 1000.085 ms","Process holding the lock: 6045. Wait q=
ueue: 6966.",,,,,"INSERT INTO myschema.mytable (...) VALUES (...)=
RETURNING process.mytable.mytable_id",13,,""<o:p></o:p></p>
<p class=3D"MsoNormal">2019-12-01 13:05:39.458 UTC,,,6045,,5de3b800.179d,1,=
,2019-12-01 12:54:24 UTC,10/417900,0,ERROR,57014,"canceling autovacuum=
task",,,,,"automatic vacuum of table ""postgres.mysche=
ma.mytable""",,,,""<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">My understanding from reading the documentation was =
that a vacuum can run concurrently with table inserts/updates, but from rea=
ding the logs it appears they are conflicting over a row lock. This p=
articular table gets very frequent inserts/updates
(10-100 inserts / sec) so I am concerned that if the autovacuum is constan=
tly canceled, then the table never gets cleaned and its performance will co=
ntinue to degrade over time. Is it expected for the vacuum to be canc=
eled by an insert in this way?<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">We are using postgres 9.6.10.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p> </o:p></p>
<p class=3D"MsoNormal">Thanks,<o:p></o:p></p>
<p class=3D"MsoNormal">Mike<o:p></o:p></p>
</div>
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Soffa Industries, Inc. nor its subsidiaries (each and collectively “K=
&S”) shall have any obligation to you to consummate the transacti=
ons herein or to enter into any agreement, other
than in accordance with the terms and conditions of a definitive agreement=
if and when negotiated, finalized and executed between the parties. This e=
mail and all its contents are protected by International and United States =
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