Optimize ROW(...) IS [NOT] NULL using non-nullable fields We break ROW(...) IS [NOT] NULL into separate tests on its component fields. During this breakdown, we can improve efficiency by utilizing expr_is_nonnullable() to detect fields that are provably non-nullable.
If a component field is proven non-nullable, it affects the outcome based on the test type. For an IS NULL test, a single non-nullable field refutes the whole NullTest, reducing it to constant FALSE. For an IS NOT NULL test, the check for that specific field is guaranteed to succeed, so we can discard it from the list of component tests. This extends the existing optimization logic, which previously only handled Const fields, to support any expression that can be proven non-nullable. In passing, update the existing constant folding of NullTests to use expr_is_nonnullable() instead of var_is_nonnullable(), enabling it to benefit from future improvements to that function. Author: Richard Guo <[email protected]> Reviewed-by: Tender Wang <[email protected]> Reviewed-by: Dagfinn Ilmari Mannsåker <[email protected]> Reviewed-by: David Rowley <[email protected]> Reviewed-by: Matheus Alcantara <[email protected]> Discussion: https://postgr.es/m/cambws49uhpbjm+nrpxerjaeufkyuzj_ajm3nbcsyk2jgz6v...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/cb7b7ec7a1c6d8933b7e731be2dd101080822cf8 Modified Files -------------- src/backend/optimizer/util/clauses.c | 49 ++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 19 deletions(-)
