PostgreSQL版:

vacuum_freeze_min_age

指定VACUUM在扫描一个表时用于判断是否用冻结行版本(在同一个事务中)。 缺省值为50百万。虽然用户可以指定一个 0-1000000000之间的值, 但是VACUUM将会悄无声息的将有效值限制在autovacuum_freeze_max_age的一半之内。 更多信息参见vacuum-for-wraparound

建议 [EN]

Most users will want to decrease this so that rows which have been cold for a long time get frozen earlier, and avoid an autovacuum_freeze. The suggestion of 500000 is for a moderately busy database; do not set to less than a few hours worth of XIDs. Maximum setting is 1/2 of autovaccuum_max_freeze_age.

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