Fix bogus calls in remove_self_join_rel() remove_self_join_rel() called adjust_relid_set() on all_result_relids and leaf_result_relids but threw away the return value. Since adjust_relid_set() returns a freshly-built Relids and does not modify the input in place, the calls did nothing. This has been the case since the SJE feature went in (commit fc069a3a6).
There has been no observable misbehavior, because the relid being passed is guaranteed not to be a member of either set. At the point remove_self_join_rel() runs, those sets contain only resultRelation; inheritance children have not been added yet, as that happens later in query_planner(), in expand_single_inheritance_child() called from add_other_rels_to_query(). And remove_self_joins_recurse() rejects parse->resultRelation as an SJE candidate to preserve the EvalPlanQual mechanism. Even with the result assigned, the calls would be no-ops in practice. Rather than make the calls do the cleanup they pretend to do, replace them with assertions of the invariant. Any future loosening of the SJE candidate filter -- for instance to allow eliminating a result relation under provable conditions -- will trip the assertion and force whoever does it to revisit this code. Additionally, decorate adjust_relid_set() with pg_nodiscard so that any future accidental discard of its return value is caught at compile time. Author: Richard Guo <[email protected]> Reviewed-by: David Rowley <[email protected]> Discussion: https://postgr.es/m/CAMbWs49fYQcqJfJ_Gtn8r1GFNoYtb1=2auab4ieuqy4zid9...@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/c66d6d19eb1a7bde17acaab421158be9cc94add8 Modified Files -------------- src/backend/optimizer/plan/analyzejoins.c | 12 ++++++++++-- src/include/rewrite/rewriteManip.h | 2 +- 2 files changed, 11 insertions(+), 3 deletions(-)
