Re: cache reads vs. disk reads

On Jul 1, 2009, at 4:20 AM, Gerd König wrote:
> b) pg_statio_user_tables=>
>
> heap_blks_read is the number of disk blocks read for that table
> (excluding index
> access), does heap_blks_hit mean the number of accesses to the
> cache for that data ?
> ...and is the number of heap_blks_read in heap_blks_hit included,
> or is this
> number the additional accesses, after reading the data from disk to
> buffer ?

Take a look in the manual; there's a pretty clear explanation in there.
--
Decibel!, aka Jim C. Nasby, Database Architect decibel(at)decibel(dot)org
Give your computer some brain candy! www.distributed.net Team #1828