maria-discuss team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxxx>]

Hi, Said!

On Mar 11, Said Ramirez wrote:
> Sergei,
> The longest transaction I currently see is ~ 3.5 hours. Which is a
> long time, and I can look into to that. I haven't seen transactions
> last days yet. Would having a transaction last hours not cause the old
> rows from being purged once those transactions have closed?  If it
> were an old or stale transaction keeping the old row versions from
> being purged, a server restart would fix the issue, no ?

Yes, a long lasting transaction would prevent old row version from being
purged even after those transactions have ended. Because a default
transaction isolation level is consistent read, which means, that if
you've seen some version of a row in a transaction, you should always
continue seeing this exactly version of this row until your transaction
ends. And InnoDB will have to keep this version and it cannot purge it.

Yes, a server restart would fix it.


> We also do see a fair amount of deadlocks. Could a thread that is
> causing the  deadlock cause old row versions from being purged even
> after the this thread is closed?

No.

Regards,
Sergei