On Wed, 18 Dec 2024 at 22:29, Richard Guo <guofengli...@gmail.com> wrote: > Should we be concerned about passing a NULL TupleTableSlotOps in > nodeRecursiveUnion.c?
I made it pass NULL on purpose because the slot type on the recursive union can be different on the inner and outer sides. Do you see issues with that? > The query below triggers the same assert > failure: the slot is expected to be TTSOpsMinimalTuple, but it is > TTSOpsBufferHeapTuple. > > create table t (a int); > insert into t values (1), (1); > > with recursive cte (a) as (select a from t union select a from cte) > select a from cte; That's a good find. I tested as far back as REL_13_STABLE and it's failing the same Assert there too. Maybe we need to backpatch passing NULL instead of &TTSOpsMinimalTuple to ExecBuildGroupingEqual() in BuildTupleHashTableExt(). Something like the attached patch. As far as I see it, there's no downside to this as ExecComputeSlotInfo() will return true anyway for the EEOP_INNER_FETCHSOME step in ExecBuildGroupingEqual() due to minimal tuples needing deformation anyway. For master, we could just do what Tom proposed above so that any callers that always use virtual slots can benefit from the elimination of the EEOP_INNER_FETCHSOME step. David
fix_incorrect_slot_type.patch
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