Thanks Peter > From: Peter Geoghegan <pg@xxxxxxx> > Sent: July 8, 2019 1:39 PM > Subject: Re: REINDEX : new parameter to preserve current average leaf density as new implicit FILLFACTOR > > Perhaps you didn't take deleted_pages into account -- there must be > free space that is reusable by the index that has yet to be reused. > It would probably make sense to subtract that across the board. > Correct, I did not, but will do so for the next runs. > > I don't think that a test case that runs VACUUM when there are only > 4300 deletions and 4300 insertions is particularly realistic, in > general. You might see a larger difference if there was more churn > between each VACUUM run. > Actually the test workload does not run any explicit VACUUM command, it relies on autovacuum with these settings (same settings for 9.4 and 12beta2) autovacuum | on | autovacuum_analyze_scale_factor | 0.4 | autovacuum_analyze_threshold | 50000 | autovacuum_max_workers | 6 | autovacuum_naptime | 20 | s autovacuum_vacuum_cost_delay | 0 | ms autovacuum_vacuum_cost_limit | 9999 | autovacuum_vacuum_scale_factor | 0 | autovacuum_vacuum_threshold | 2000 | autovacuum_work_mem | 1048576 | kB To correspond to your " more churn between each VACUUM" Would you then suggest increasing autovacuum_vacuum_cost_delay and/or autovacuum_vacuum_scale_factor? Cheers, John Lumby
