Re: Making jsonb_agg() faster

jian he <jian(dot)universality(at)gmail(dot)com> writes:
> outcontext will always be NULL in 0001.
> that means copyScalarSubstructure is never really called.
> it also means that JsonbInState->MemoryContext was always as NULL in 00001
> maybe we don't need JsonbInState->MemoryContext in 0001
> So 0001 refactoring change would be less invasive.

I think you're missing the point: per the commit message for 0001,

The real reason for doing it is to provide a mechanism whereby
pushJsonbValue() can be told to construct the JsonbValue tree
in a context that is not CurrentMemoryContext. That happens
when a non-null "outcontext" is specified in the JsonbInState.
No callers exercise that option in this patch, but the next
patch in the series will make use of it.

If we didn't add the outcontext option in this step, we'd just
have to do so in the next one.

regards, tom lane