po 5. 8. 2019 v 10:10 odesÃlatel Thomas Kellerer <spam_ea...@gmx.net> napsal:
> Pavel Stehule schrieb am 05.08.2019 um 08:19: > >>> I have seen some hacks suggesting TRY/CATCH or converting to a JSON > >>> and checking if the field exists, but I would think that there's a > >>> better way to check if the field is in the NEW record, no? > > > >> I assume using to_jsonb(new) and then check for the key in the json > value > >> will be faster than checking e.g. information_schema.column > >> or pg_catalog.pg_attribute > > > > Alternative solution can be using other language than PLpgSQL - > > PLPythonu or PLPerl (there it is simple task). This language is not > > designed for too dynamic code. PLpgSQL triggers are designed for > > stable schema - you should to know if table has email column or not. > > > > Catching errors in PLpgSQL is relative expensive solution due related > > savepoint overhead in background. > Yes, exception handling (or a catalog lookup) is expensive. > That's why I suggested that using to_jsonb() has the least overhead. > > The check is then as simple as: > > if (to_jsonb(new) ? 'email') then > ... do something > end if; > casting from record to jsonb is not gratis too :). But surely, it is cheaper than savepoints. Pavel > Thomas > > >
