>
>
> On Tue, May 25, 2010 at 1:48 PM, Balkrishna Sharma <
b_ki@hotmail.com> wrote:
>>
>> Hi,
>> I am increasing the shared_buffer size in postgresql.conf and want to
>> measure its effect on READ. In essence I want to know if the SELECT queries
>> I am firing repeatedly is reading from the buffer or going directly to the
>> disk.
>> I am expecting the first SELECT to go to disk and the subsequent call of
>> the same SELECT to read from buffer .
>> Right now I am just looking at execution time of the SELECTs and trying to
>> conclude. But there should be a direct way to see where the SELECT reads
>> from.
>
> You can also use pg_stat_database view. you can compute cache reads
> percentage of the total number of reads (cache and physical) between the two
> snapshots using pg_stat_database.blks_hit and pg_stat_database.blks_read.
