The Postgres version is 9.3.9. The actual output of the lock query is (I added *locktype* and *mode* columns from the *pg_locks* table)
*blocked_pid*: 7574 *blocked_statement*: UPDATE "TRANSLATION" SET fk_assignment_queue_item = 1009184 WHERE id IN (47049861) *blocked_locktype*: transactionid *blocked_mode*: ShareLock *blocked_duration*: 00:35:01.81106 *blocking_pid*: 7569 *blocking_statement*: select tmtranslat0_.id as id164_0_, tmtranslat1_.id as id101_1_, tmlanguage2_.id as id73_2_, tmtranslat0_.status as status164_0_, ... *blocking_locktype*: transactionid *blocking_mode*: ExclusiveLock *blocking_duration*: 00:35:03.017109 User names are irelevant, so I omitted that. Also the *blocking_statement* is actually cut off even before the FROM clause, but there is only one SELECT query issued at that moment which matches the start: select from "TRANSLATION" tmtranslat0_left outer join "TRANSLATION_UNIT" tmtranslat1_ on tmtranslat0_.fk_id_translation_unit = tmtranslat1_.idleft outer join "LANGUAGE" tmlanguage2_ on tmtranslat0_.fk_id_language = tmlanguage2_.idwhere tmtranslat0_.id in (47049860, 47049861, 47049862)order by tmtranslat0_.id asc I also suspected a SELECT FOR UPDATE query, but it's not the case. Also, I don't use these at all in the application. Tom Lane-2 wrote > So either the SELECT is a SELECT FOR UPDATE, or it's part of a transaction > that's done datachanges in the past. If these are the only two explanations, it must be the latter then. What I still don't understand - these two statements are part of the same transaction (because the lock query joins on the lock's transaction id), so it looks like a transaction blocking itself. As I think about it now, it does not even make sense to me /why/ the lock query joins on the lock.transactionid - I would expect two locks will mostly conflict with each other when they are executed within /different/ transactions. As for other context, I fail to see how this situation is special or different from any other...Is there any pattern I should be looking for? -- View this message in context: http://postgresql.nabble.com/SELECT-blocks-UPDATE-tp5862040p5862091.html Sent from the PostgreSQL - general mailing list archive at Nabble.com.
