c7be3c015b
The initial building of RestrictInfos and SpecialJoinInfos tends to create structures that share relid sets (such as syn_lefthand and outer_relids). There's nothing wrong with that in itself, but when we modify those relid sets during join removal, we have to be sure not to corrupt the values that other structures are pointing at. remove_rel_from_query() was careless about this. It accidentally worked anyway because (1) we'd never be reducing the sets to empty, so they wouldn't get pfree'd; and (2) the in-place modification is the same one that we did or will apply to the other struct's relid set, so that there wasn't visible corruption at the end of the process. While there's no live bug in a standard build, of course this is way too fragile to accept going forward. (Maybe we should back-patch this change too for safety, but I've refrained for now.) This bug was exposed by the recent invention of REALLOCATE_BITMAPSETS. Commit e0477837c had installed a fix, but that went away with the reversion of SJE, so now we need to fix it again. David Rowley and Tom Lane Discussion: https://postgr.es/m/CACJufxFVQmr4=JWHAOSLuKA5Zy9H26nY6tVrRFBOekHoALyCkQ@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/.