Re: Need help understanding pg_locks

Bruce Momjian <bruce@momjian.us> wrote:
> 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".
> vaguely represented the locked object.
I think more accurately:
Information about the lock requester:
virtualtransaction, pid
Information about what is being locked:
database, relation, page, tuple, virtualxid, transactionid, classid,
objid, objsubid (where NULL means "not applicable to this lock)
Information about the lock itself:
locktype, mode, granted
-Kevin