Em 08-06-2011 20:35, Robert Haas escreveu:
Is the hint correct? I mean, what if there were 100 small tables that
needed vacuuming all at the same time. We'd hit this limit no matter
how high you set autovacuum_max_workers, but it wouldn't be right to
set it to 101 just because every once in a blue moon you might trip
over the limit.
I think so. You are picturing a scene with only one message. It is the same
case of the too-frequent-checkpoint messages; i.e., you should look if those
messages have some periodicity.
I think it'd be really useful to expose some more data in this area
though. One random idea is - remember the time at which a table was
first observed to need vacuuming. Clear the timestamp when it gets
vacuumed. Then you can do:
Hmmm. But this fine grained information alone doesn't help tuning the number
of autovacuum workers. I consider counters easier to implement and simpler to
analyze. But the timestamp idea has its merit because we already have a
similar statistic (last timestamp table was vacuumed or analyzed).
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Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/
PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento
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