Re: INSERT waiting under heavy load - Mailing list pgsql-sql

From Tom Lane
Subject Re: INSERT waiting under heavy load
Date
Msg-id 23072.1136584149@sss.pgh.pa.us
Whole thread Raw
In response to Re: INSERT waiting under heavy load  (alex-lists-pgsql@yuriev.com)
Responses Re: INSERT waiting under heavy load  (Andrew Sullivan <ajs@crankycanuck.ca>)
List pgsql-sql
alex-lists-pgsql@yuriev.com writes:
> if the problem is caused by the the acquire lock->modify column->release
> lock on the table 1, then why does it increase significantly increase as the
> number of entries in the table 3 grows? The simulation maintains pretty much
> constant rate of new requests coming to table 3.

Are you vacuuming table 1 on a regular basis while you do this?
Accumulation of dead tuple versions in table 1 is a pretty severe
performance risk in the sort of scenario you are describing.
(I'm not sure why it would manifest as transactions showing "INSERT
waiting" state though.)
        regards, tom lane


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