Re: Harry Ambrose 2017-08-25 <CAK4Knu86q98fWNzYntsZk1uGca6F129wLShmrkzyb2EZkSMDWQ@xxxxxxxxxxxxxx> > Hi All, > > Sorry to open this can of worms again. However, we are still struggling > with this issue across quite a large amount of our estate. Hi, we've just seen exactly this error on a customer database running 9.5.3 (postgresql95.x86_64 9.5.3-2PGDG.rhel6). Luckily just one tuple was affected. Symptoms were: # select text from k... where id = 719764749; ERROR: unexpected chunk number 0 (expected 1) for toast value 3347468184 in pg_toast_922511637 The toast table itself was perfectly ok, with a single chunk: # select * from pg_toast.pg_toast_922511637 where chunk_id = 3347468184; chunk_id | 3347468184 chunk_seq | 0 chunk_data | ...valid text string... (with bytea_output = 'escape') Updating or deleting the field/row didn't work: # update k... set text = '...same text as above...' where id = 719764749; ERROR: XX000: tuple concurrently updated ORT: simple_heap_delete, heapam.c:3171 # delete from k... where id = 719764749; ERROR: XX000: tuple concurrently updated ORT: simple_heap_delete, heapam.c:3171 The problem persisted over the last two weeks (eventually noticed by pg_dump starting to fail between August 15th and 18th). The server was started on July 26th. Besides the ERRORing statements above, I didn't actively resolve it, suddenly SELECTing the original row just worked again. According to pg_stat_user_tables, autovacuum didn't hit in. I can't say if there were backends open for two weeks. At the time it resolved itself, the oldest backend was from August 27th. If xmin/xmax/multixact... data from this server is interesting, I can extract it on request. Christoph -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
