Re: Strange deadlock with object/target of lock : transaction

Laurenz Albe <laurenz.albe@cybertec.at>

From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Achilleas Mantzios <a.mantzios@cloud.gatewaynet.com>, pgsql-general@lists.postgresql.org
Date: 2025-08-26T06:22:42Z
Lists: pgsql-general
On Mon, 2025-08-25 at 15:40 +0100, Achilleas Mantzios wrote:
> > > > > We've been hit by a weird deadlock which it took me some days to isolate and replicate.
> > > > > It does not have to do with order of updates or any explicit TABLE-level locking,
> > > > > the objects/targets of the deadlock in question are transactions. 
> 
> Hi I reproduced without the triggers, I understood the problem, I believe the system's
> behavior is the intended, I am sorry for the false alarm. The thing is that it takes >=3
> transactions to happen . That was the tricky part, up to now in all cases of deadlocks
> we had two transactions involved, this one needed three or more.

Yes, waiting for a transaction means that you are waiting for a row lock.
See https://www.cybertec-postgresql.com/en/row-locks-in-postgresql/

Yours,
Laurenz Albe