Re: Need help understanding pg_locks - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Need help understanding pg_locks
Date
Msg-id 201107111531.p6BFVIi09965@momjian.us
Whole thread Raw
In response to Re: Need help understanding pg_locks  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Need help understanding pg_locks
Re: Need help understanding pg_locks
List pgsql-hackers
Tom Lane wrote:
> Florian Pflug <fgp@phlo.org> writes:
> > On Jul11, 2011, at 17:11 , Tom Lane wrote:
> >> Yeah, I think this patch is going in the wrong direction altogether.
> >> It would be better to modify the description of virtualtransaction
> >> and pid to say that those are the "locking" entity.
> 
> > Hm, we already kinda of say that. Both descriptions include the phrase
> > "... holding or awaiting this lock.". The column "mode" says
> > "... held or desired by this process", which I guess is similar enough
> > to make it clear that these are related.
> 
> > Its the columns which refer to the locked object which simply say 
> > "object", and thus leave it open if that means locked or a locking.
> 
> > Could we split that table in two parts, one for the fields referring
> > to the locked object and one for the locking entity, or does that depart
> > too far from the way we document other system catalogs and views?
> 
> Then you'd have to join them, which would not be an improvement from
> anybody's standpoint.
> 
> Maybe we could just add a paragraph above the "pg_locks Columns" table
> that says explicitly that virtualtransaction and pid describe the entity
> holding or awaiting the lock, and the others describe the object being
> locked?  Any way you slice it, putting this information into the
> per-column table is going to be repetitive.

Frankly, whenever anyone says "object", they might as well call it
"thing".  It seems to be a content-less word.  Maybe just replace the
word "object" with "lock".

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +


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