Re: Change in CTE treatment in query plans?

Hi Tom -

Thanks so much for getting back to me.

I didn't realise that the costs of init/sub plans would be spread across
the call sites - I had (stupidly) assumed that each call site would
include the full cost.

Having taken a couple of days to go back over the problems I was seeing,
you were absolutely right - it was all to do with multiple call sites -
the postgres version was just a red herring.

Thanks for your help & all the best,

Dave

On 17/10/2019 10:04, Tom Lane wrote:
> David Conlin <dc345(at)cantab(dot)net> writes:
>> Does anyone know if there's been a change in the way values for CTEs are
>> displayed in query plans?
> Offhand I don't recall any such changes, nor does a cursory look
> through explain.c find anything promising.
>
> If you're concerned with a multiply-referenced CTE, one possibility
> for funny results is that the blame for its execution cost could be
> spread across the multiple call sites. The same can happen with
> initplans/subplans. But I'm just guessing; you didn't show any
> concrete examples so it's hard to be definite.
>
> regards, tom lane