Re: Timing out A Blocker Based on Time or Count of Waiters

On 3/22/24 09:25, Fred Habash wrote:
> Facing an issue where sometimes humans login to a database and run DDL
> statements causing a long locking tree of over 1000 waiters. As a

The above needs more explanation:

1) Define locking tree.

2) Define waiters.

3) Provide examples of the DDL.

> workaround, we asked developers to always start their DDL sessions
> with 'SET lock_timeout = 'Xs'.
>
> I reviewed the native lock timeout parameter in Postgres and found 7.
> None seem to be related to blocker timeouts directly.
>
> idle_in_transaction_session_timeout
> idle_session_timeout
> lock_timeout: How long a session waits for a lock
> statement_timeout
> authentication_timeout
> deadlock_timeout
> log_lock_waits
>
> Instead, I put together a quick procedure that counts waiter sessions
> for a given blocker and terminates it if waiter count exceeds a threshold.
>
> Is there not a native way to ...
> 1. Automatically time out a blocker
> 2. A metric that shows how many waiters for a blocker?
>
> Thanks
> --
>
> ----------------------------------------
> Thank you
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com