Re: Patch: Show process IDs of processes holding a lock; show relation and tuple infos of a lock to acquire

Hi,

On 22/01/14 12:40, Simon Riggs wrote:
> > 1. I find a issue in following scenario:
> >
> >         session 1 with process id X: BEGIN; LOCK TABLE foo IN SHARE MODE;
> >         session 2 with process id Y: BEGIN; LOCK TABLE foo IN EXCLUSIVE MODE;
> >         session 3 with process id Z: BEGIN; LOCK TABLE foo IN SHARE MODE;
> >
> >         On execution of LOCK in session-3, as part of log it will display as:
> >                 processes owning lock: X, Y
> >         But actually if we see Y has not yet own the lock, it is still waiting with higher priority.
> >         It may mislead user.
> >         May be we should change message to give all meaning i.e. which process is owning lock and
> >         Which process is already in queue.
>
> Perhaps this?
>
> CONTEXT: lock owner XXXX request queue XXX, XXX, XXX, etc

Fixed.

> > 2. Can we give a better name to new variable 'buf1'?

Fixed.

> > 3. Do we need to take performance reading to see if any impact?
>
> Don't think so. Diagnosing problems will help performance, not hinder it

I agree. And this code path will only get executed when log_lock_waits
= on, which seems to be a debugging method to me.

Best regards,

--
 Christian Kruse               http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services