![]() The suggestions in the other answers so far won't help at least.ĭisclaimer: I don't have innotop installed and I didn't bother. Adding another covering index (state, ownerid, weight) index for linkclick saved about 80 on the UPDATE JOIN select. You can use INFORMATION_SCHEMA.INNODB_TRX, performance_schema.events_statements_history and performance_schema.threads to extract the queries that any active transactions have executed in the past as outlined in my other answer, but I haven't come across any way to see that someTable is locked in the above scenario. TY TY Adding the the covering index for linkweight saved about 50 of the time on the INSERT SELECT select. SHOW FULL PROCESSLIST is empty, because the culprit is not actually running a query right now. SHOW ENGINE INNODB STATUS is useless: someTable is not mentioned at all INFORMATION_SCHEMA.INNODB_LOCKS is empty, which makes sense given the documentation, because there is only one transaction and currently nobody waiting for any locks. Its used in the same place as NOWAIT and, like NOWAIT, affects. The reason is if I have a row, I would do an update operation rather than insert. PostgreSQL 9.5 introduces a new SKIP LOCKED option to SELECT. But no query is going on right now and nobody is waiting for a lock anywhere (yet at least). Now what I want is to prevent the deadlock by making the select from alert a where a.serverid 'x' and a.alertid 1 for update block any operations that involve that select statement. but no rollback or commit - just let it sit thereĬlearly the transaction above holds a lock, because the transaction is still active. FOR SHARE), try using a lower isolation level such as READ COMMITTED. ![]() Update someTable set name="foobar" where ID=1234 Previous Deadlock Detection Home MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0 Up Deadlocks in InnoDB Next Transaction Scheduling. Is that correct This depends on the concurrency control your database system is using. None of the answers can show all the locks that are currently held.ĭo this e.g. To solve this problem, Thread 1 should SELECT id FROM rooms FOR UPDATE, thereby preventing Thread 2 from deleting from rooms until Thread 1 is done. A deadlock can occur when transactions lock rows in multiple tables (through statements such as UPDATE or SELECT.
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