Aldor <an(at)mediaroot(dot)de> writes:
> bgwriter_percent = 0
> bgwriter_maxpages = 0
Why did you do that? There's certainly nothing in the docs recommending
disabling the bgwriter.
> The duration of the VACUUM of tbl1 and tbl2 is okay - so how to speed up
> now the VACUUM of tbl3?
You have not showed us anything that would explain any speed differences
between these tables. Maybe there was some difference in the data you
loaded them with?
regards, tom lane