On Fri, Aug 9, 2024 at 1:02 AM David Rowley <dgrowleyml@xxxxxxxxx> wrote:
On Fri, 9 Aug 2024 at 02:12, Christophe Pettus <xof@xxxxxxxxxxxx> wrote:
> VACUUM FULL takes an exclusive lock on the table that it is operating on. It's possible that a connection becomes blocked on that exclusive lock waiting for the VACUUM FULL to finish, the application sees the connection stopped and fires up another one (this is common in container-based applications), that one blocks... until all of the connections are full of queries waiting on that VACUUM FULL.
I also imagine this is the cause. One way to test would be to do:
BEGIN; LOCK TABLE <name of table>; and see if the connections pile up
in a similar way to when the VACUUM FULL command is used.
David
Thanks folks. David really straight-forward way to test. I validated this, when I lock the two tables involved in the benchmark the connections are constantly growing until they reach the `max_connections`
