Re: How much do the hint bits help?
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Merlin Moncure <mmoncure@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-12-22T00:45:17Z
Lists: pgsql-hackers
Merlin Moncure <mmoncure@gmail.com> writes: > Attached is an incomplete patch disabling hint bits based on compile > switch. ... > So far, at least doing pgbench runs and another test designed to > exercise clog lookups, the performance loss of always doing full > lookup hasn't materialized. The standard pgbench test would be just about 100% useless for stressing this, because its net database activity is only about one row touched/updated per query. You need a test case that hits lots of rows per query, else you're just measuring parse+plan+network overhead. regards, tom lane