Tom Lane wrote:
> Florian Pflug <fgp@phlo.org> writes:
> > On Jul11, 2011, at 05:47 , Bruce Momjian wrote:
> >> Thank you. I think my confusion is that virtualtransaction is the lock
> >> holder/waiter, and the other two are actual locks. The attached doc
> >> patch clarifies that. I had actually realized this a few weeks ago and
> >> forgot, meaning this is pretty confusing.
>
> > For consistency, I guess it should say "lock object" instead of simply
> > "object" the description of all the columns up to (and including)
> > "objsubid", not only those of "virtualxid" and "transactionid".
>
> 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.
OK, so as I understand it, in pg_locks:
Column | Type | Modifiers--------------------+----------+----------- locktype | text |
database | oid | relation | oid | page | integer | tuple |
smallint| virtualxid | text | transactionid | xid | classid | oid | objid
| oid | objsubid | smallint |
virtualtransaction | text | pid | integer | mode | text | granted |
boolean |
It is the last four that are related to the "locking entity". I don't
see a way of improving the description of the last four columns:
http://developer.postgresql.org/pgdocs/postgres/view-pg-locks.html
What was unclear to me was that the earlier columns (illogically)
vaguely represented the locked object.
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ It's impossible for everything to be true. +
