6572bd55b0
The executor only supports CurrentOfExpr as the sole tidqual of a TidScan plan node. tidpath.c failed to take any particular care about that, but would just take the first ctid equality qual it could find in the target relation's baserestrictinfo list. Originally that was fine because the grammar prevents any other WHERE conditions from being combined with CURRENT OF <cursor>. However, if the relation has RLS visibility policies then those would get included in the list. Should such a policy include a condition on ctid, we'd typically grab the wrong qual and produce a malfunctioning plan. To fix, introduce a simplistic priority ordering scheme for which ctid equality qual to prefer. Real-world cases involving more than one such qual are so rare that it doesn't seem worth going to any great trouble to choose one over another, so I didn't work very hard; but this code could be extended in future if someone thinks differently. It's extremely difficult to think of a reasonable use-case for an RLS restriction involving ctid, and certainly we've heard no field reports of this failure. So this doesn't seem worthy of back-patching, but in the name of cleanliness let's fix it going forward. Patch by me, per report from Robert Haas. Discussion: https://postgr.es/m/3914881.1715038270@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.
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.
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