Gregory Stark <st...@enterprisedb.com> wrote: > >> I don't think we can perfectly capture the meaning of these GUCs in the > >> name. I think our goal should be to avoid confusion between them. > > I was thinking it would be clearer if the options which control *when* > autovacuum fires off a worker consistently had some action word in them like > "trigger" or "start" or "launch".
I think we need more explanations about those variables, not only "how to work" but also "how to tune" them. I feel they are un-tunable parameters. Our documentation says: | Larger values of these settings | preserve transactional information longer, while smaller values increase | the number of transactions that can elapse before the table must be | vacuumed again. i.e, we are explaining the variables only as "Larger is better", but is it really true? I think we should have answers about the following questions: - What relation are there between autovacuum_freeze_max_age, vacuum_freeze_min_age and vacuum_freeze_table_age? If we increase one of them, should we also increase the others? - Is it ok to increase the variables to maximum values? Are there any trade-off? - Are there some conditions where whole-table-scanning vacuum is more effective than vacuums using visibility map? If so, we should switch to full-scan *automatically*, without relying on user configurations. Regards, --- ITAGAKI Takahiro NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
