Trigger efficiency

Hi,

I've the following problem and I don't know how to solve it: There is a
table with about 10-12 fields, a couple of those fields are updated very
often (about 30 times / minute or even more). This is my table (more or
less):

crete table monitor(
time Timestamp,
time2 timestamp,
...
status int,
);

I need to know how many rows are in the table and keep that number to
another table every time that there is an INSERT or DELETE on that
table, so I made a trigger that fires on insert and delete events and
calls a function that makes de update on the new table, that works well.
My problem starts when I have to count the rows depending on the status
field: I added a UPDATE on my trigger and it works! :)...... my trigger:

CREATE TRIGGER tr_barra_aps AFTER INSERT OR DELETE OR UPDATE
ON monitor EXECUTE PROCEDURE f_barra_aps();

But now, this trigger fires too often and there is an extra load on the
system that makes everything run slower. I posted before a question
asking about firing triggers on specific columns...thats not possible. I
don't know how to solve it, perhaps I should do it without
triggers.....any help will be appreciated

thanks!

--
Josep Sanmarti
Analista de Projectes

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