f5050f795a
When generating window_pathkeys, distinct_pathkeys, or sort_pathkeys, we failed to realize that the grouping/ordering expressions might be nullable by grouping sets. As a result, we may incorrectly deem that the PathKeys are redundant by EquivalenceClass processing and thus remove them from the pathkeys list. That would lead to wrong results in some cases. To fix this issue, we mark the grouping expressions nullable by grouping sets if that is the case. If the grouping expression is a Var or PlaceHolderVar or constructed from those, we can just add the RT index of the RTE_GROUP RTE to the existing nullingrels field(s); otherwise we have to add a PlaceHolderVar to carry on the nullingrel bit. However, we have to manually remove this nullingrel bit from expressions in various cases where these expressions are logically below the grouping step, such as when we generate groupClause pathkeys for grouping sets, or when we generate PathTarget for initial input to grouping nodes. Furthermore, in set_upper_references, the targetlist and quals of an Agg node should have nullingrels that include the effects of the grouping step, ie they will have nullingrels equal to the input Vars/PHVs' nullingrels plus the nullingrel bit that references the grouping RTE. In order to perform exact nullingrels matches, we also need to manually remove this nullingrel bit. Bump catversion because this changes the querytree produced by the parser. Thanks to Tom Lane for the idea to invent a new kind of RTE. Per reports from Geoff Winkless, Tobias Wendorff, Richard Guo from various threads. Author: Richard Guo Reviewed-by: Ashutosh Bapat, Sutou Kouhei Discussion: https://postgr.es/m/CAMbWs4_dp7e7oTwaiZeBX8+P1rXw4ThkZxh1QG81rhu9Z47VsQ@mail.gmail.com
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/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/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/.