On Mon, Sep 25, 2017 at 9:13 AM, Denisa Cirstescu < denisa.cirste...@tangoe.com> wrote:
> > Can someone please explain to me why this worked? > > What happened behind the scenes? > > I suspect that when you catch exceptions inside of a LOOP and the code > ends up generating an exception, Postgres can’t use cached plans to > optimize that code so it ends up planning the code at each iteration and > this causes performance issues. > > Is my assumption correct? > > > Not sure how much detail you are looking for but the docs say this: "Tip: A block containing an EXCEPTION clause is significantly more expensive to enter and exit than a block without one. Therefore, don't use EXCEPTION without need." https://www.postgresql.org/docs/current/static/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING I'm somewhat doubting "plan caching" has anything to do with this; I suspect its basically that there is high memory and runtime overhead to deal with the possibilities of needing to convert a exception into a branch instead of allowing it to be fatal. David J.
