Suppose I have a table tbl with columns (a, b, c, counter). And I have 5 ON UPDATE triggers assigned to this table. They process (a, b, c) columns, but never depend on counter.
I need to update counter field, but I know that it is totally independent, so - for performance reason I want to temporarily disable all triggers during the tbl.counter updation. How could I do it?
(Please do not offer ALTER TABLE tbl DISABLE TRIGGER ALL. It is NOT a production case: ALTER TABLE locks all the table during, so it cannot be used in heavy-loaded systems.) (Please do not also offer top move the counter to another table, because it is used in complex indices, e.g. INDEX ON (counter, a, c) to speedup fetching.)
Possible solution: add an additional column named "disable_trg" BOOLEAN: (a, b, c, disable_trg). Then, I use the following UPDATE:
UPDATE tbl SET counter = counter + 1, disable_trg = true WHERE a = 10;
In each trigger I firstly run an instruction:
IF NEW.disable_trg THEN RETURN NEW; END IF;
And the latest trigger resets disable_trg field to NULL, so it is not written to the table. So, in some queries I may explicitly specify do I need to disable triggers or not.
But this solution (the only possible?) looks like a brute-force method. Possibly Postgrs has another one, better?