On 10-09-24 03:06 PM, Bob Lunney wrote:
The pertinent difference between pg_stat_user_indexes and pg_statio_user_indexes is the latter shows the number of blocks read from disk or found in the cache.
I have a minor, but very important correction involving this point. The pg_statio tables show you what blocks are found in the Postgres buffer cache, and what ones are not.
For the ones that are not, those blocks may come from the OS filesystem cache, a battery backed cache, or on the actual disk. There is a big difference in performance based on where you are actually getting those blocks from (and you can't this info from Postgres).
-- Brad Nicholson 416-673-4106 Database Administrator, Afilias Canada Corp. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
