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Commitf836b688fensured that at most one clone of a join clause is chosen for a parameterized path, so long as the clone variants are parse-tree distinct. Two ways remained to end up enforcing the same condition more than once, which wastes execution effort and applies the clause's selectivity multiple times, underestimating the row count. If a commuting outer join nulls no Var referenced by a particular qual, the clone variants of that qual are parse-tree identical, and the incompatible_relids test cannot tell them apart. To fix, enforce just the first surviving variant, identified by rinfo_serial. The other case is in get_joinrel_parampathinfo, where the clause-recovery pass for dropped EquivalenceClasses queries the EC machinery with a context that overlaps the preceding loop's, so the derived-clause cache can hand back a clause that that loop already accepted. To fix, skip any clause that is already present in the collected list. Also add assertions verifying that the clauses to be enforced at a join or within a parameterized path contain no duplicate rinfo_serial, to catch any remaining or future violations. These assertions are added in master only, since hard prevention of duplicate clauses is a new goal and other unfixed cases may remain. Back-patch to v19, as with commitf836b688f. Author: Richard Guo <guofenglinux@gmail.com> Author: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/CAMbWs4_Ezb1Lnj7BqcTQSysC6B5UFZxfhib8xr6rqpu5uqr8dA@mail.gmail.com Backpatch-through: 19
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/19/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/19/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.