Horton

Re: How much expensive are row level statistics?

Bruce Momjian <pgman@candle.pha.pa.us>

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From: Bruce Momjian <pgman@candle.pha.pa.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Fuhr <mike@fuhr.org>, Merlin Moncure <merlin.moncure@rcsonline.com>, pgsql-performance@postgresql.org, Carlos Benkendorf <carlosbenkendorf@yahoo.com.br>
Date: 2005-12-17T02:44:19Z
Lists: pgsql-hackers, pgsql-performance 
Tom Lane wrote:
> Michael Fuhr <mike@fuhr.org> writes:
> > Further tests show that for this application
> > the killer is stats_command_string, not stats_block_level or
> > stats_row_level.
> 
> I tried it with pgbench -c 10, and got these results:
> 	41% reduction in TPS rate for stats_command_string

Woh, 41%.  That's just off the charts!  What are we doing internally
that would cause that?

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