Steve Clark <steve.clark@xxxxxxxxxxxxx> writes: > No. But I examined the pg_log/log_file and saw an error indicating it was autovacuum: > 2016-10-27 09:47:02 EDT:srm2api:12968:LOG: sending cancel to blocking autovacuum PID 12874 > 2016-10-27 09:47:02 EDT:srm2api:12968:DETAIL: Process 12968 waits for ExclusiveLock on relation 955454549 of database 955447411. > 2016-10-27 09:47:02 EDT:srm2api:12968:STATEMENT: lock table t_unit_status_log in exclusive mode > 2016-10-27 09:47:02 EDT::12874:ERROR: canceling autovacuum task > 2016-10-27 09:47:02 EDT::12874:CONTEXT: automatic vacuum of table "srm2.public.t_unit_status_log" That kicked the autovacuum off the table, but it didn't help because you still had a deadlock condition afterwards: > 2016-10-27 09:47:02 EDT:srm2api:9189:ERROR: deadlock detected at character 8 > 2016-10-27 09:47:02 EDT:srm2api:9189:DETAIL: Process 9189 waits for RowExclusiveLock on relation 955454549 of database 955447411; blocked by process 12968. > Process 12968 waits for ExclusiveLock on relation 955454518 of database 955447411; blocked by process 9189. > Process 9189: update t_unit_status_log set status_date = now ( ) , unit_active = 'y' , last_updated_date = now ( ) , last_updated_by = current_user , devices_down = $1 where unit_serial_no = $2 > Process 12968: lock table t_unit in exclusive mode > So I feel pretty confident this is the issue. I guess I should retry the update in my application. Retrying might be a usable band-aid, but really this is an application logic error. The code that is trying to do "lock table t_unit in exclusive mode" must already hold some lower-level lock on t_unit, which is blocking whatever the "update t_unit_status_log" command wants to do with t_unit. Looks like a classic lock-strength-upgrade mistake to me. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
