On Mon, 2024-04-08 at 16:25 +0530, jaya kumar wrote: > I am not clear. I can confirm that. > Could you explain again. If I delete 20 records out of 100. It means Autocacumm should run > but not run automatically. As you provide a solution, the method should be deleted but does not happen. If you delete 20 rows, autovacuum should not run. > Delete record=30 > > autovacuum_vacuum_threshold + autovacuum_vacuum_scale_factor * number of table rows ? > o/p: 20+0.1*100=2010? I don't know what an o/p is, but that calculation is wrong. > DatabaseName=# show autovacuum_vacuum_threshold; > autovacuum_vacuum_threshold > ----------------------------- > 20 > (1 row) > > DatabaseName=# show autovacuum_vacuum_scale_factor; > autovacuum_vacuum_scale_factor > -------------------------------- > 0.1 > (1 row) > > DatabaseName=# select count(*) from emp9; > count > ------- > 100 > (1 row) > > DatabaseName=# delete from emp9 where eno between 1 and 30; Try deleting 31 or 32 rows. Statistics are not necessarily 100% accurate. > On Mon, Apr 8, 2024 at 3:15 PM Laurenz Albe <laurenz.albe@xxxxxxxxxxx> wrote: > > On Mon, 2024-04-08 at 14:57 +0530, jaya kumar wrote: > > > autovacuum_analyze_threshold and autovacuum_vacuum_threshold both parameter > > > values set from 50 to 20. > > > > > > Created one table with 100 records. First, we deleted 21 records. after an > > > autovacuum does not happen automatically. After again I deleted another 20. > > > Out of 100 we delectated 40 records then the autovacuum happened automatically. > > > As per the configuration Autocacuum will automatically delete 21 records > > > in the table but my case does not happen. > > > > > > Can someone check and explain this. > > > > The threshold is > > > > autovacuum_vacuum_threshold + autovacuum_vacuum_scale_factor * number of table rows > > > > So since you have set autovacuum_vacuum_scale_factor to 0.1 and there are 100 rows, > > you need to delete 20 + 100 * 0.1 = 30 rows before autovacuum kicks in. Please bottom-post. Yours, Laurenz Albe
