Re: minimal update - Mailing list pgsql-hackers

Right. In fact, I already had that part in fact - see 
http://people.planetpostgresql.org/andrew/index.php?/archives/22-Minimal-Update-Trigger.html

What I was waiting for was the part where it gets put in the catalog, 
documented, etc.

cheers

andrew

Bruce Momjian wrote:
> 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
>>>>     
>>>>         
>>>   
>>>       
>
>