Re: obtaining row locking information

> Tatsuo, are you planning to add this to CVS HEAD?

Yes, I would like to add if there's no objection.
--
Tatsuo Ishii
SRA OSS, Inc. Japan

> ---------------------------------------------------------------------------
> 
> Tatsuo Ishii wrote:
> > I have attached pgrowlocks tested under current.
> > --
> > Tatsuo Ishii
> > SRA OSS, Inc. Japan
> > 
> > > Tatsuo, have you developed a new version of this for 8.2?
> > > 
> > > ---------------------------------------------------------------------------
> > > 
> > > Tatsuo Ishii wrote:
> > > > > Tatsuo Ishii <t-ishii@sra.co.jp> writes:
> > > > > > To accomplish this I need to add following function into
> > > > > > storage/ipc/procarray.c. This is similar to BackendPidGetProc() except
> > > > > > that it accepts xid as an argument. Any objection?
> > > > > 
> > > > > >     if (xid == 0)                /* never match dummy PGPROCs */
> > > > > >         return NULL;
> > > > > 
> > > > > I think this test should be against InvalidTransactionId, not "0", and
> > > > > the comment is wrong (you are suppressing matches against idle PGPROCs).
> > > > > 
> > > > > Also note the comment at the top of the function: once you release
> > > > > ProcArrayLock you have no guarantee that the result means anything at
> > > > > all; and unlike ProcSendSignal, you have no reason to think that the
> > > > > target backend can't quit before you get another cycle.  It might be
> > > > > better to return the pid directly rather than assuming it'll still be
> > > > > meaningful to indirect through a returned pointer.
> > > > 
> > > > Agreed.
> > > > 
> > > > > Also, what are you going to do about prepared transactions?  They can
> > > > > hold locks but they don't have PIDs.  On the whole, I'm not sure this
> > > > > is a good idea at all, because of that.
> > > > 
> > > > For prepared transactions, just showing "0" pids are enough, I
> > > > think. Assuming that in practice most transactions are not prepared
> > > > ones, I think the function is not perfect, but is usefull enough for
> > > > most DBAs.
> > > > --
> > > > Tatsuo Ishii
> > > > 
> > > 
> > > -- 
> > >   Bruce Momjian   http://candle.pha.pa.us
> > >   SRA OSS, Inc.   http://www.sraoss.com
> > > 
> > >   + If your life is a hard drive, Christ can be your backup. +
> > > 
> 
> [ Attachment, skipping... ]
> 
> -- 
>   Bruce Momjian   http://candle.pha.pa.us
>   EnterpriseDB    http://www.enterprisedb.com
> 
>   + If your life is a hard drive, Christ can be your backup. +
>