-hackers,
I'm working on a vacuum verbose log analyzer for a few weeks now. My
goal is to allow a more systematic study of this log output to help
improve the vacuum strategy.
To do so, I spent a few hours studying the vacuum code and especially
the way it logs what it's doing.
What surprises me is:
* the inconsistency between the display of the duration for lazy
vacuum and vacuum full (especially the index cleanup included in the
former case and not in the latter)
* the fact that there are quite a lot of work done outside of the
duration calculated and displayed in the log (the
vacuum_heap/repair_frag step for example).
The consequence is that it's really hard to figure out how much time
was elapsed for each table.
Moreover in the case of a vacuum analyze, the analyze operation is not
included at all in the time elapsed and we can't know how long it was
for each table.
I attached an analysis on how it works currently.
I'd like to be able to find in the log the time really elapsed for
each operation.
I'll probably be able to write a patch for this but I'd like to know
if anybody else think it's worth it and if anybody has advice/ideas on
how to do it nicely.
Regards,
--
Guillaume
