272 posts tagged with "Issues"

KILL failed with ERROR 1095 (HY000): You are not owner of thread 183. An ordinary account can only stop its own connections, so this one needs another account's help, or a privilege that shouldn't go to an application.

A plain SELECT printed ERROR 2013 (HY000): Lost connection to MySQL server during query, then No connection. Trying to reconnect..., and then showed a result as if nothing had happened. Something had happened: the open transaction was gone, and my session was a new one.

A statement that had been waiting ended suddenly with ERROR 1317 (70100): Query execution was interrupted. MySQL didn't give up by itself: another session stopped it with KILL QUERY. The statement had no effect, and the connection is fine.

I ran ROLLBACK, and MySQL answered Query OK, and my UPDATE was still there. A CREATE TABLE in between had quietly committed it. MySQL doesn't warn you, and the ROLLBACK has nothing to report.

An ALTER TABLE on a tiny table was still running minutes later, and the connection's state said Waiting for table metadata lock. The cause was the last thing I'd have looked at: a transaction that ran one SELECT and never ended. This is also what a stuck migration usually looks like.

Another session changed a row and committed, and I could see that it worked. In my transaction, the same SELECT kept returning the old number. Nothing's broken: under MySQL's default isolation level, a transaction keeps reading from the snapshot it took at its first read.

A statement ending in \G works when you type it at the mysql> prompt, and fails with ERROR at line 1: Unknown command '\G'. when it comes from --execute or a script. The command didn't go anywhere. The newer client just turns its own commands off when it isn't interactive.

A SELECT stopped after a second with ERROR 3024 (HY000): Query execution was interrupted, maximum statement execution time exceeded. Nothing crashed: a time limit did its job. The right fix depends on whether the query is too slow, or the limit too strict.

ROLLBACK TO SAVEPOINT failed with ERROR 1305 (42000): SAVEPOINT a does not exist. A savepoint only lasts as long as you let it: releasing it removes it, and so does the end of the transaction.

ERROR 1792 (25006): Cannot execute statement in a READ ONLY transaction means the statement tries to change something that a read-only transaction isn't allowed to touch. The straightforward case is an UPDATE, and the less obvious one is creating a temporary table.