Re: Want function to be called only once in query

On Thu, Sep 16, 2021 at 4:51 AM Steve Pritchard <steve.pritchard@bto.org> wrote:
>
> I have a PL/pgSQL function that I want to call within a query, but the function is fairly expensive to execute so I only want it executed once within the query. However the planner seems to reorganize my query so that it calls the function for every row.
>
> We were previously on Pg 9.6 and this wasn't a problem then. But now that we have upgraded to Pg 13, the behaviour has changed.
>

The behavior for planning a CTE changed in PG12.

> There must be a "proper" way to get the planner to call a function only once.
>
Add the MATERIALIZED keyword to the WITH statement