Re: Why would writes to pgsql_tmp bottleneck at 1mb/s? - Mailing list pgsql-performance

From Aaron Birkland
Subject Re: Why would writes to pgsql_tmp bottleneck at 1mb/s?
Date
Msg-id 19ab0ccd05030817132e702cd4@mail.gmail.com
Whole thread Raw
In response to Re: Why would writes to pgsql_tmp bottleneck at 1mb/s?  (Josh Berkus <josh@agliodbs.com>)
List pgsql-performance
> Maybe I'm not an idiot (really!)  even with almost 2GB of maintenance_mem, PG
> still writes to pgsql_tmp no faster than 2MB/s.    I think there may be an
> artificial bottleneck there.  Question is, PostgreSQL, OS or hardware?

I'm curious: what is your cpu usage while this is happening?  I've
noticed similar slow index creation behaviour, but I did not make any
connection to pgsql_temp (because it was not on a separate partition).
 I was indexing an oid field of a 700GB table and it took about four
days on a 1.2GHz UltraSparcIII (solaris 9, 8GB core).  I noticed that
the one CPU that was  pegged at near 100%, leading me to believe it
was CPU bound.  Odd thing is that the same operation on a 2GHz Pentium
IV box (Linux) on the same data took about a day.    Truss showed that
a great majority of that time was in userland.

    -Aaron

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