Re: [HACKERS] More detail on settings for pgavd?

On Thu, 2003-11-20 at 19:40, Matthew T. O'Connor wrote:
> I'm open to discussion on changing the defaults. Perhaps what it would
> be better to use some non-linear (perhaps logorithmic) scaling factor.
> So that you wound up with something roughly like this:
>
> #tuples activity% for vacuum
> 1k 100%
> 10k 70%
> 100k 45%
> 1M 20%
> 10M 10%
> 100M 8%
>

Just thinking out loud here, so disregard if you think its chaff but...
if we had a system table pg_avd_defaults that held what we generally
consider the best default percentages based on reltuples/pages, and
added a column to pg_class (could be some place better but..) which
could hold an overriding percentage, you could then have a column added
to pg_stat_all_tables called vacuum_percentage, which would be a
coalesce of the override percentage or the default percentages based on
rel_tuples (or rel_pages). This would give autovacuum a place to look
for each table as to when it should vacuum, and gives administrators the
option to tweak it on a per table basis if they find they need a
specific table to vacuum at a different rate than the "standard".

Robert Treat
--
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