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Partition pruning for RANGE-partitioned tables could mistakenly prune the DEFAULT partition in some cases when it was not valid to do so, which could lead to rows missing from query results. The only known cases where this could happen is when combining pruning steps from an IS NOT NULL clause with other steps that matched to the DEFAULT partition. This could occur due to RANGE partitioned tables having two distinct internal representations for marking if the DEFAULT partition should be scanned. The IS NOT NULL steps would mark the "scan_default" boolean, but other steps created for different purposes could mark a bound_offset Bitmapset, which would ultimately translate into also scanning the default partition. This could all fail after multiple steps were combined with a combine intersect operator, as that will intersect the bound_offset bits and only set scan_default if all pruning steps have that flag set. When both input steps to the intersect operator had different representations of whether to scan the DEFAULT partition, the resulting intersect step result would contain neither representation. Here, we fix this by having the IS NOT NULL pruning result mark the bound_offsets so that it uses both representations to mark that the DEFAULT partition must be scanned. Reported-by: Jacob Brazeal <jacob.brazeal@gmail.com> Diagnosed-by: Jacob Brazeal <jacob.brazeal@gmail.com> Author: David Rowley <dgrowleyml@gmail.com> Discussion: https://postgr.es/m/CA+COZaDXrfTaBjLE=Z79MTaH6Xun1V4PeKxLvCNv8mXS8wn0rw@mail.gmail.com Backpatch-through: 14
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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.