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refresh_by_match_merge() has some issues in the way it builds a SQL query to construct the "diff" table: 1. It doesn't require the selected unique index(es) to be indimmediate. 2. It doesn't pay attention to the particular equality semantics enforced by a given index, but just assumes that they must be those of the column datatype's default btree opclass. 3. It doesn't check that the indexes are btrees. 4. It's insufficiently careful to ensure that the parser will pick the intended operator when parsing the query. (This would have been a security bug before CVE-2018-1058.) 5. It's not careful about indexes on system columns. The way to fix #4 is to make use of the existing code in ri_triggers.c for generating an arbitrary binary operator clause. I chose to move that to ruleutils.c, since that seems a more reasonable place to be exporting such functionality from than ri_triggers.c. While #1, #3, and #5 are just latent given existing feature restrictions, and #2 doesn't arise in the core system for lack of alternate opclasses with different equality behaviors, #4 seems like an issue worth back-patching. That's the bulk of the change anyway, so just back-patch the whole thing to 9.4 where this code was introduced. Discussion: https://postgr.es/m/13836.1521413227@sss.pgh.pa.us
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/.