Hi,
I need to speed up the triggers that we are using and I began to make
some tests to compare the "C" and pgSQL trigger performance.
I try to write two identical test triggers (sorry I do not know very
good the pgsql C interface and I got one of examples and werite it) and
attached it on insert of my test table.
After it I try to insert in thi stable ~ 160 K rows and compared the
speeds.
I was supprised that the pgsql trigger take ~8 sec. to insert this rows
and the "C" trigger take ~ 17 sec.
This are my triggers:
CREATE OR REPLACE FUNCTION trig1_t()
RETURNS trigger AS
'
DECLARE
my_rec RECORD;
BEGIN
select into my_rec count(*) from ttest;
RETURN NEW;
END;
'
LANGUAGE 'plpgsql' VOLATILE;
and this writen in "C":
#include "postgres.h"
#include "executor/spi.h" /* this is what you need to work with
SPI */
#include "commands/trigger.h" /* ... and triggers */
extern Datum trigf(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(trigf);
Datum
trigf(PG_FUNCTION_ARGS)
{
TriggerData *trigdata = (TriggerData *) fcinfo->context;
TupleDesc tupdesc;
HeapTuple rettuple;
char *when;
bool checknull = false;
bool isnull;
int ret, i;
/* make sure it's called as a trigger at all */
if (!CALLED_AS_TRIGGER(fcinfo))
elog(ERROR, "trigf: not called by trigger manager");
/* tuple to return to executor */
if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
rettuple = trigdata->tg_newtuple;
else
rettuple = trigdata->tg_trigtuple;
/* check for null values */
if (!TRIGGER_FIRED_BY_DELETE(trigdata->tg_event)
&& TRIGGER_FIRED_BEFORE(trigdata->tg_event))
checknull = true;
if (TRIGGER_FIRED_BEFORE(trigdata->tg_event))
when = "before";
else
when = "after ";
tupdesc = trigdata->tg_relation->rd_att;
/* connect to SPI manager */
if ((ret = SPI_connect()) < 0)
elog(INFO, "trigf (fired %s): SPI_connect returned %d", when,
ret);
/* get number of rows in table */
ret = SPI_exec("SELECT count(*) FROM ttest", 0);
if (ret < 0)
elog(NOTICE, "trigf (fired %s): SPI_exec returned %d", when,
ret);
SPI_finish();
if (checknull)
{
SPI_getbinval(rettuple, tupdesc, 1, &isnull);
if (isnull)
rettuple = NULL;
}
return PointerGetDatum(rettuple);
}
My question:
Can I do the "C" trigger to be faster that the pgSQL?
regards,
ivan.