Re: DETOASTing in custom memory context

tgl wrote:
> strk <strk@keybit.net> writes:
> >> From whitin an aggregate sfunc I did:
> >         oldcontext = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);
> >         geom = (GEOMETRY *)PG_DETOAST_DATUM(datum);
> >         MemoryContextSwitchTo(oldcontext);
> 
> > And later in aggregate's finalfunc:
> >     pfree(geom);
> 
> > Result:
> >     segfault!
> 
> > What's wrong with it ?
> 
> Perhaps you wanted PG_DETOAST_DATUM_COPY().  Or possibly use
> PG_FREE_IF_COPY() rather than an unconditional pfree, though
> that would depend on just what your usage pattern is.

Sure, how did I miss that !
PG_FREE_IF_COPY is unapplicable here since pfree() call is in a
different function that the one DETOASTING it (finalfunc and sfunc
respectively of an aggregate), but PG_DETOAST_DATUM_COPY() did at
least force a copy and thus the context-switch...

thanks,
--strk;