On 26.9.2012 18:29, Tom Lane wrote:
> What seems to me like it could help more is fixing things so that the
> autovac launcher needn't even launch a child process for databases that
> haven't had any updates lately. I'm not sure how to do that, but it
> probably involves getting the stats collector to produce some kind of
> summary file.
Couldn't we use the PgStat_StatDBEntry for this? By splitting the
pgstat.stat file into multiple pieces (see my other post in this thread)
there's a file with StatDBEntry items only, so maybe it could be used as
the summary file ...
I've been thinking about this:
(a) add "needs_autovacuuming" flag to PgStat_(TableEntry|StatDBEntry)
(b) when table stats are updated, run quick check to decide whether the table needs to be processed by autovacuum
(vacuumedor analyzed), and if yes then set needs_autovacuuming=true and both for table and database
The worker may read the DB entries from the file and act only on those
that need to be processed (those with needs_autovacuuming=true).
Maybe the DB-level field might be a counter of tables that need to be
processed, and the autovacuum daemon might act on those first? Although
the simpler the better I guess.
Or did you mean something else?
regards
Tomas
