Matt Magoffin <postgresql(dot)org(at)msqr(dot)us> writes:
> I’m essentially doing a datumCopy() on every non-null input value.
If you're doing that in the aggContext, you definitely need to free
the prior one(s).
> I was wondering if there is a way to free the previously copied datum, since I don’t really need it anymore? Something like
> if (state->last != NULL) {
> pfree(state->last);
> }
Not quite like that. Look into nodeAgg.c, which solves a similar problem
for the transvalues themselves with code like
/* forget the old value, if any */
if (!oldIsNull && !pertrans->inputtypeByVal)
pfree(DatumGetPointer(oldVal));
regards, tom lane