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a5f412107f
If a CHECKPOINT record with nextMulti N is written to the WAL before
the CREATE_ID record for N, and N happens to be the first multixid on
an offset page, the backwards compatibility logic to tolerate WAL
generated by older minor versions (before commit 789d65364c) failed to
compensate for the missing XLOG_MULTIXACT_ZERO_OFF_PAGE record. In
that case, the latest_page_number was initialized at the start of WAL
replay to the page for nextMulti from the CHECKPOINT record, even if
we had not seen the CREATE_ID record for that multixid yet, which
fooled the backwards compatibility logic to think that the page was
already initialized.
To fix, track the last XLOG_MULTIXACT_ZERO_OFF_PAGE that we've seen
separately from latest_page_number. If we haven't seen any
XLOG_MULTIXACT_ZERO_OFF_PAGE records yet, use
SimpleLruDoesPhysicalPageExist() to check if the page needs to be
initialized.
Reported-by: duankunren.dkr <duankunren.dkr@alibaba-inc.com>
Analyzed-by: duankunren.dkr <duankunren.dkr@alibaba-inc.com>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Discussion: https://www.postgresql.org/message-id/c4ef1737-8cba-458e-b6fd-4e2d6011e985.duankunren.dkr@alibaba-inc.com
Backpatch-through: 14-18
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/.