Thread

Re: obtaining row locking information

Tatsuo Ishii <t-ishii@sra.co.jp> — 2005-08-12T03:27:25Z

> Hi,
> 
> With a help from Bruce, I wrote a small function which returns row
> locking information(see attached file if you are interested). Here is
> a sample result:
> 
> test=# select * from pgrowlocks('t1');
>  locked_row | lock_type | locker | multi 
> ------------+-----------+--------+-------
>       (0,1) | Shared    |      1 | t
>       (0,3) | Exclusive |    575 | f
> (2 rows)
> 
> I think it will be more usefull if actual xids are shown in the case
> "locker" is a multixid. It seems GetMultiXactIdMembers() does the
> job. Unfortunately that is a static funtcion, however. Is there any
> chance GetMultiXactIdMembers() becomes public funtion?

I enhanced pgrowlocks() to use GetMultiXactIdMembers() so that it
displays each xid belonging to particular multi xid (see attached
source code).

test=# select * from pgrowlocks('t1');
 locked_row | lock_type | locker | multi |   xids    
------------+-----------+--------+-------+-----------
      (0,1) | Shared    |      3 | t     | {646,647}
(1 row)

However even one of transactions, for example 647 commits, still it
shows as if 647 is a member of muitixid 3.

test=# select * from pgrowlocks('t1');
 locked_row | lock_type | locker | multi |   xids    
------------+-----------+--------+-------+-----------
      (0,1) | Shared    |      3 | t     | {646,647}
(1 row)

Am I missing something?
--
Tatsuo Ishii