On Mon, 4 Mar 2019 at 04:42, Tom Lane <t...@sss.pgh.pa.us> wrote: > > David Rowley <david.row...@2ndquadrant.com> writes: > > On Sun, 3 Mar 2019 at 17:11, Tom Lane <t...@sss.pgh.pa.us> wrote: > >> (At the code level, this is implicit in the fact that the comparison > >> function will be called via FunctionCall2Coll or a sibling, and those > >> all throw an error if the called function returns NULL.) > > > Ah okay. I can get it to misbehave by setting fcinfo->isnull = true in > > the debugger from int4eq(). I see the NULL result there is not > > verified as that's just translated into "false" by ExecInterpExpr()'s > > EEOP_QUAL case. If you're saying something doing that is > > fundamentally broken, then I guess we're okay. > > No, what I'm thinking of is this bit in _bt_compare: > > result = DatumGetInt32(FunctionCall2Coll(&scankey->sk_func, > scankey->sk_collation, > datum, > scankey->sk_argument)); > > You absolutely will get errors during btree insertions and searches > if a datatype's btree comparison functions ever return NULL (for > non-NULL inputs).
I understand this is the case if an index happens to be used, but there's no guarantee that's going to be the case. I was looking at the case where an index was not used. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
