31ed3cf746
Previously we did this after InitPostgres, at a somewhat randomly chosen place within PostgresMain. However, since commit a0ffa885e doing this outside a transaction can cause a crash, if we need to check permissions while replacing a placeholder GUC. (Besides which, a preloaded library could itself want to do database access within _PG_init.) To avoid needing an additional transaction start/end in every session, move the process_session_preload_libraries call to within InitPostgres's transaction. That requires teaching the code not to call it when InitPostgres is called from somewhere other than PostgresMain, since we don't want session_preload_libraries to affect background workers. The most future-proof solution here seems to be to add an additional flag parameter to InitPostgres; fortunately, we're not yet very worried about API stability for v15. Doing this also exposed the fact that we're currently honoring session_preload_libraries in walsenders, even those not connected to any database. This seems, at minimum, a POLA violation: walsenders are not interactive sessions. Let's stop doing that. (All these comments also apply to local_preload_libraries, of course.) Per report from Gurjeet Singh (thanks also to Nathan Bossart and Kyotaro Horiguchi for review). Backpatch to v15 where a0ffa885e came in. Discussion: https://postgr.es/m/CABwTF4VEpwTHhRQ+q5MiC5ucngN-whN-PdcKeufX7eLSoAfbZA@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. 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/.