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When pull_up_sublinks() converts a sublink to an antijoin, it builds a JoinExpr with no RTE, on the grounds that nothing above the join can reference its RHS. That overlooks PlaceHolderVars. A PHV with no Vars of its own is evaluated at its phrels, and for the outputs of a pulled-up subquery phrels is all the relids in the subquery's jointree, including the RHS of such a join. A qual using the PHV thus appears to reference the RHS rels, and can be pushed down into the RHS as a parameterized join clause. There it has the opposite of the intended effect: outer rows that fail the qual find no match and are emitted, giving wrong results. For an outer join, including an antijoin made by reducing a left join, this cannot happen because the join's relid is among the qual's relids. Before v16, the qual's nullable_relids prevented it. To fix, make a join RTE for an antijoin built from a sublink, so that it has a relid like any other outer join. Semijoins are left as they are: a qual evaluated within a semijoin's RHS does not change the result. Back-patch to v16. Before that, the qual's nullable_relids included the antijoin's RHS, which kept the qual from being moved there; that protection went away when nullable_relids was replaced by outer-join relids. Author: Richard Guo <guofenglinux@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Reviewed-by: wenhui qiu <qiuwenhuifx@gmail.com> Discussion: https://postgr.es/m/CAMbWs4_rEdcG89BgC-AO7b+Bf2z8w3976+4zP==Urt=CXB1hsg@mail.gmail.com Backpatch-through: 16
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/18/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/18/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/.