Greg Stark <st...@mit.edu> writes: > On Wed, Apr 4, 2012 at 9:34 PM, Simon Riggs <si...@2ndquadrant.com> wrote: >> Why is this pgbench run accessing so much unhinted data that is > 1 >> million transactions old? Do you believe those numbers? Looks weird.
> I think this is in the nature of the workload pgbench does. Because > the updates are uniformly distributed, not concentrated 90% in 10% of > the buffers like most real-world systems, (and I believe pgbench only > does index lookups) the second time a tuple is looked at is going to > average N/2 transactions later where N is the number of tuples. That's a good point, and it makes me wonder whether pgbench is the right test case to be micro-optimizing around. It would be a good idea to at least compare the numbers for something with more locality of reference. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers