Re: minimal update - Mailing list pgsql-hackers

Andrew Dunstan wrote:
> 
> Not that I know of.  I never saw Gurjeet's completed code.

This is Gurjeet's code, but it is not complete.
http://archives.postgresql.org/pgsql-hackers/2008-03/msg00668.php

---------------------------------------------------------------------------

> 
> cheers
> 
> andrew
> 
> Bruce Momjian wrote:
> > Is there a version of this patch ready for application?
> >
> > ---------------------------------------------------------------------------
> >
> > Gurjeet Singh wrote:
> >   
> >> On Tue, Mar 18, 2008 at 7:46 PM, Andrew Dunstan <andrew@dunslane.net> wrote:
> >>
> >>     
> >>>
> >>>
> >>>
> >>> Gurjeet Singh wrote:
> >>>       
> >>>> On Fri, Mar 7, 2008 at 9:40 PM, Bruce Momjian <bruce@momjian.us
> >>>> <mailto:bruce@momjian.us>> wrote:
> >>>>
> >>>>
> >>>>     I assume don't want a TODO for this?  (Suppress UPDATE no changed
> >>>>     columns)
> >>>>
> >>>>
> >>>> I am starting to implement this. Do we want to have this trigger
> >>>> function in the server, or in an external module?
> >>>>
> >>>>
> >>>>         
> >>> I have the trigger part of this done, in fact. What remains to be done
> >>> is to add it to the catalog and document it. The intention is to make it
> >>> a builtin as it will be generally useful. If you want to work on the
> >>> remaining parts then I will happily ship you the C code for the trigger.
> >>>
> >>>
> >>>       
> >> In fact, I just finished writing the C code and including it in the catalog
> >> (Just tested that it's visible in the catalog). I will test it to see if it
> >> does actually do what we want it to.
> >>
> >> I have incorporated all the suggestions above. Would love to see your code
> >> in the meantime.
> >>
> >> Here's the C code:
> >>
> >> Datum
> >> trig_ignore_duplicate_updates( PG_FUNCTION_ARGS )
> >> {
> >>     TriggerData *trigData;
> >>     HeapTuple oldTuple;
> >>     HeapTuple newTuple;
> >>
> >>     if (!CALLED_AS_TRIGGER(fcinfo))
> >>         elog(ERROR, "trig_ignore_duplicate_updates: not called by trigger
> >> manager.");
> >>
> >>     if( !TRIGGER_FIRED_BY_UPDATE(trigData->tg_event)
> >>         && !TRIGGER_FIRED_BEFORE(trigData->tg_event)
> >>         && !TRIGGER_FIRED_FOR_ROW(trigData->tg_event) )
> >>     {
> >>         elog(ERROR, "trig_ignore_duplicate_updates: Can only be executed for
> >> UPDATE, BEFORE and FOR EACH ROW.");
> >>     }
> >>
> >>     trigData =  (TriggerData *) fcinfo->context;
> >>     oldTuple = trigData->tg_trigtuple;
> >>     newTuple = trigData->tg_newtuple;
> >>
> >>     if (newTuple->t_len == oldTuple->t_len
> >>         && newTuple->t_data->t_hoff == oldTuple->t_data->t_hoff
> >>         && HeapTupleHeaderGetNatts(newTuple->t_data) ==
> >> HeapTupleHeaderGetNatts(oldTuple->t_data)
> >>         && (newTuple->t_data->t_infomask & ~HEAP_XACT_MASK)
> >>             == (oldTuple->t_data->t_infomask & ~HEAP_XACT_MASK)
> >>         && memcmp( (char*)(newTuple->t_data) + offsetof(HeapTupleHeaderData,
> >> t_bits),
> >>                 (char*)(oldTuple->t_data) + offsetof(HeapTupleHeaderData,
> >> t_bits),
> >>                     newTuple->t_len - offsetof(HeapTupleHeaderData, t_bits)
> >> ) == 0 )
> >>     {
> >>         /* return without crating a new tuple */
> >>         return PointerGetDatum( NULL );
> >>     }
> >>
> >>     return PointerGetDatum( trigData->tg_newtuple );
> >> }
> >>
> >>
> >>
> >> -- 
> >> gurjeet[.singh]@EnterpriseDB.com
> >> singh.gurjeet@{ gmail | hotmail | indiatimes | yahoo }.com
> >>
> >> EnterpriseDB http://www.enterprisedb.com
> >>
> >> 17? 29' 34.37"N, 78? 30' 59.76"E - Hyderabad *
> >> 18? 32' 57.25"N, 73? 56' 25.42"E - Pune
> >> 37? 47' 19.72"N, 122? 24' 1.69" W - San Francisco
> >>
> >> http://gurjeet.frihost.net
> >>
> >> Mail sent from my BlackLaptop device
> >>     
> >
> >   

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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