| 类型: | integer |
| 默认: | 50000000 |
| 最低限度: | 0 |
| 最大: | 1000000000 |
| 上下文: | user |
| 重新开始: | false |
指定VACUUM在扫描表时用来决定是否冻结行版本的切断年龄（以事务计）。默认值是 5 千万个事务。尽管用户可以将这个值设置为从 0 到 10 亿，VACUUM会悄悄地将有效值设置为autovacuum_freeze_max_age值的一半，这样在强制执行的自动清理之间不会有过短的时间间隔。更多信息请见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.