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Re: Copying database files


> Am 13.08.2018 um 12:22 schrieb Ling, Andy:
> >> "The advantage of FLUSH TABLES table_name FOR EXPORT is that the
> table
> >> is read locked until UNLOCK TABLES is executed" is not really true
> >> because that's only valid for the running connection
> >
> > Surely not. If you've locked a table for read only nothing should be able to
> write to it from any connection otherwise what's the point of a multi-
> threaded server? Tests suggest otherwise.
> "Another item to be aware of with this statement is that the read lock
> is released as soon as the session that made the call ends. When the
> pre-freeze-script finishes, the session is closed" - try it out
> and how do you make a script that locks the table and continues without
> closing the session to mysqld?

This is being driven by a Java program. It opens a connection using the mariadb-java-client. That connection isn't released until the end of the copying process when the tables are unlocked and then it only goes back into a pool, so may not be closed at all.


Andy Ling

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