Hi, > On 10 Dec 2025, at 00:08, Andres Freund <[email protected]> wrote: > I don't really see this being viable without first tackling two nontrivial > projects: > > 2) Perform ScanKey evaluation in slot form, to be able to cache the deforming > and to make deforming of multiple columns sufficiently efficient.
Am I right in understanding that you think that the repeated calls to heap_getattr in HeapKeyTest is not ideal if we have NULL or varlena columns? I have written a small patch (see attached) that stores the heap tuple in a TupleTableSlot first and then calls slot_getattr instead, which should benefit from caching. Is that the type of solution you were thinking of? It is definitely not a complete patch (needs comments and a description), and it is not merged into the patch set of Julien yet, but I just wanted to check that this was what you were proposing and that I was not misunderstanding something. > 1) Make slot deforming for expressions & projections selective, i.e. don't > deform all the leading columns, but only ones that will eventually be > needed Concerning 1), I’m also not certain I understand why this is a prerequisite for the pushdown work. It could certainly be beneficial, but it seems to be complementary. In any case, I’d be interested to look at your POC patch on the subject, Amit. Best, Maxime Schoemans
Perform-ScanKey-evaluation-in-slot-form.patch
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