Gokulakannan Somasundaram wrote:
> I was going to say that I'm really only interested in physical I/O. Logical
>> I/O which is satisfied by the kernel cache is only marginally interesting
>> and
>> buffer fetches from Postgres's shared buffer is entirely uninteresting
>> from
>> the point of view of trying to figure out what is slowing down a query.
>
> Ok the Physical I/Os are already visible, if you enable log_statement_stats.
I think you missed the point. What log_statement_stats shows are not
physical I/Os, they're read() system calls. Unfortunately there's no
direct way to tell if a read() is satisfied from OS cache or not. Greg's
suggestion was about how to do that.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com
