Murthy Nunna <mnunna@xxxxxxxx> writes: > I did pg_dump of a ~20TB database followed by pg_restore. I find simple queries like select count(*) running slow. I did a select count(*) on all tables before pg_dump which took ~4 hours. After pg_restore, same thing took 32 hours. My bet is that that was setting commit hint bits, and hence incurring a lot of writes. If the data is reasonably stable that's a one-time expense. regards, tom lane
