Title: RE: [PERFORM] pg_reset_stats + cache I/O %

Thanks Tom, sorry I neglected to copy the list on my previous email.....

Does this query make sense and is it valid for an accurate cache % hit ratio for the entire DB?  I would assume I could use the same logic with other views such as pg_stat_user_tables to get a per table ratio?

SELECT 100 - round((blks_hit::numeric / (blks_hit::numeric + blks_read::numeric)) * 100,2)
AS "Cache % Hit"
FROM pg_stat_database
WHERE datname = 'Fix1';

<RETURNS>

Cache % Hit
--------------------
       98.06
(1 row)

Thank you,
Tim

 -----Original Message-----
From:   Tom Lane [mailto:[EMAIL PROTECTED]]
Sent:   Tuesday, March 07, 2006 2:37 PM
To:     mcelroy, tim
Cc:     'pgsql-performance@postgresql.org'
Subject:        Re: [PERFORM] pg_reset_stats + cache I/O %

"mcelroy, tim" <[EMAIL PROTECTED]> writes:
> ERROR:  function round(double precision, integer) does not exist

Try coercing to numeric instead of float.  Also, it'd be a good idea to
put that coercion outside the sum()'s instead of inside --- summing
bigints is probably noticeably faster than summing numerics.

                        regards, tom lane

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