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.
