Hi everyone, I just got the same issue on 9.6.8:
2018-05-15 11:52:01 MSK 33558 @ from [vxid:317/92895305 txid:0] [] ERROR: found xmin 2808837517 from before relfrozenxid 248712603 2018-05-15 11:52:01 MSK 33558 @ from [vxid:317/92895305 txid:0] [] CONTEXT: automatic vacuum of table "template0.pg_catalog.pg_authid" Additional details: 1) bt_index_check - no errors on both indexes. 2) SELECT pg_truncate_visibility_map('pg_authid'::regclass); + vacuum freeze - doesn't help. 3)Total 6 rows affected: template1=# select oid, ctid, xmin, xmax, cmin, cmax from pg_authid where xmin::text::bigint > (select relfrozenxid::text::bigint from pg_class where relname='pg_authid'); oid | ctid | xmin | xmax | cmin | cmax -----------+--------+------------+------+------+------ 183671986 | (0,90) | 3039161773 | 0 | 0 | 0 183106699 | (1,48) | 2576823237 | 0 | 0 | 0 183921770 | (1,50) | 3265971811 | 0 | 0 | 0 183921914 | (1,52) | 3266122344 | 0 | 0 | 0 187988173 | (1,58) | 4258893789 | 0 | 0 | 0 182424977 | (1,62) | 2808837517 | 0 | 0 | 0 on total two pages. 4) template1=# select relfrozenxid from pg_catalog.pg_class where relname = 'pg_authid'; relfrozenxid -------------- 2548304492 5)Rows itself looks pretty valid and correspond to the actual database users. 7)No database/server crash happened last few years, no disk errors/problems. I feel it could be related with vacuum skip locked pages patch + freeze + shared catalog combination, but cannot prove it yet. Looking for possible course of action. Probably simplest fix - drop and recreate these 6 affected users, but so far I willing spent some time research into this issue. -- Maxim Boguk Senior Postgresql DBA http://dataegret.com/ <http://www.postgresql-consulting.com/> Phone RU: +7 985 433 0000 Phone UA: +380 99 143 0000 Phone AU: +61 45 218 5678 LinkedIn: http://www.linkedin.com/pub/maksym-boguk/80/b99/b1b Skype: maxim.boguk "Доктор, вы мне советовали так не делать, но почему мне по-прежнему больно когда я так делаю ещё раз?"