On 2018-05-15 11:06:38 +0200, Maxim Boguk wrote: > 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. Yea, too late. > 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. Could you use pageinspect to get the infomasks for the affected tuples? Greetings, Andres Freund