On Sun, 2009-08-16 at 02:02 +0300, Peter Eisentraut wrote: > For min, the action happens at or above the min values. For max, the > action happens at or below the max value.
>From the docs, 23.1.4: "autovacuum is invoked on any table that might contain XIDs older than the age specified by the configuration parameter autovacuum_freeze_max_age" I interpret that to mean that the forced autovacuum run happens above the value. You could reasonably call it the "minimum age of relfrozenxid that will cause autovacuum to forcibly run a vacuum". Similarly, you could call vacuum_freeze_min_age "the maximum age a tuple can be before a vacuum will freeze it". I'm not trying to be argumentative, I'm just trying to show that it can be confusing if you interpret it the wrong way. The first time I saw those configuration names, I was confused, and ever since, I have to think about it: "is that variable called min or max?". My general feeling is that both of these are thresholds. The only real maximum happens near wraparound. > With those two particular parameters, the freezing happens exactly > between the min and the max value. Thanks, that's a helpful way to remember it. It may be a little obsolete because now the freezing will normally happen between vacuum_freeze_min_age and vacuum_freeze_table_age; but at least I should be able to remember which of the other parameters is "min" and which one is "max". Regards, Jeff Davis -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers