a4f18fd8f2
The Recovery section said we would "operate correctly without the full page
images that MarkBufferDirtyHint() provides", offering them only as a way to
lose less slot knowledge to RBM_ZERO_ON_ERROR. That is true of freespace.c,
which passes RBM_ZERO_ON_ERROR on every read, and false of the system around
it, which reads the same files and does verify checksums. Reading it as a
licence to dirty FSM pages without a full page image is what led to
c06d1a4ba6, since reverted.
Say instead that RBM_ZERO_ON_ERROR is a property of this directory rather
than of the fork, and name the readers that do not share it:
RelationCopyStorage(), RelationCopyStorageUsingBuffer(), base backups and
pg_checksums. Rather than presenting today's behavior as the only one
possible, note that the alternative is for all of that code to skip checksum
validation of the FSM.
Reported-by: Noah Misch <noah@leadboat.com>
Reviewed-by: Noah Misch <noah@leadboat.com>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/20260901211837.f6.noahmisch%40microsoft.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/.