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Commit a4d75c86b improved the extended-stats logic to allow extended stats to be collected on expressions not just bare Vars. To apply such stats, we first verify that the user has permissions to read all columns used in the stats. (If not, the query will likely fail at runtime, but the planner ought not do so.) That had to get extended to check permissions of columns appearing within such expressions, but the code for that was completely wrong: it applied pull_varattnos to the wrong pointer, leading to "unrecognized node type" failures. Furthermore, although you couldn't get to this because of that bug, it failed to account for the attnum offset applied by pull_varattnos. This escaped recognition so far because the code in question is not reached when the user has whole-table SELECT privilege (which is the common case), and because only subexpressions not specially handled by statext_is_compatible_clause_internal() are at risk. I think a large part of the reason for this bug is under-documentation of what statext_is_compatible_clause() is doing and what its arguments are, so do some work on the comments to try to improve that. Per bug #17570 from Alexander Kozhemyakin. Patch by Richard Guo; comments and other cosmetic improvements by me. (Thanks also to Japin Li for diagnosis.) Back-patch to v14 where the bug came in. Discussion: https://postgr.es/m/17570-f2f2e0f4bccf0965@postgresql.org
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/.