On Fri, Jan 11, 2013 at 9:02 AM, Heikki Linnakangas <hlinnakan...@vmware.com > wrote:
> On 11.01.2013 12:36, Matheus de Oliveira wrote: > >> On Fri, Jan 11, 2013 at 8:19 AM, Heikki Linnakangas<hlinnakangas@** >> vmware.com <hlinnakan...@vmware.com> >> >>> wrote: >>> >> >> One thing that caught my eye: >>> >>> CREATE OR REPLACE FUNCTION partition_insert_trigger_spi() >>> >>>> RETURNS trigger >>>> LANGUAGE C >>>> VOLATILE STRICT >>>> AS 'partition_insert_trigger_spi'****,'partition_insert_trigger_*** >>>> *spi' >>>> SET DateStyle TO 'ISO'; >>>> >>> >>> Calling a function with SET options has a fair amount of overhead, to >>> set/restore the GUC on every invocation. That should be avoided in a >>> performance critical function like this. >>> >> >> I (stupidly) used SPI_getvalue [1] and expected it to always return as >> YYYY-MM-DD, but them I remembered it would do that only with >> DateStyle=ISO. >> >> But the truth is that I couldn't see any overhead, because the function >> was >> without that on my first tests, and after that I saw no difference on the >> tests. >> > > Oh, ok then. I would've expected it to make a measurable difference. > > > I think I should use SPI_getbinvalue instead, but I don't know how >> to parse the result to get year and month, any help on that? >> > > The fastest way is probably to use j2date like date_out does: > > DateADT date = DatumGetDateADT(x) > int year, month, mday; > > if (DATE_NOT_FINITE(date)) > elog(ERROR, "date must be finite"); > j2date(date + POSTGRES_EPOCH_JDATE, &year, &month, &mday); > > - Heikki > Nice. With the modifications you suggested I did saw a good improvement on the function using SPI (and a little one with heap_insert). So I was wrong to think that change the GUC would not make to much difference, the SPI code now runs almost as fast as the heap_insert: heap_insert: 31896.098 ms SPI: 36558.564 Of course I still could make some improvements on it, like using a LRU to keep the plans, or something like that. The new code is at github. Regards, -- Matheus de Oliveira Analista de Banco de Dados Dextra Sistemas - MPS.Br nível F! www.dextra.com.br/postgres
