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bf25c5f832
GiST neglected to invalidate its killedItems[] array on a rescan. As a
result, it was just about possible for the wrong tuples from the wrong
index page to be LP_DEAD-marked on a rescan. The scan mistakenly
believed that the previous rescan's killedItems[] were for this rescan's
curBlkno, causing index corruption.
To fix, bring GiST in line with nbtree and hash: call gistkillitems from
both gistrescan and gistendscan (the existing gistgettuple caller still
handles the common case where we need to LP_DEAD-mark before moving on
to the next page). That way the scan's pending killedItems[] are passed
to gistkillitems while they still describe items from curBlkno. When
gistkillitems runs, it'll invalidate the array in passing (and won't
needlessly miss out on an opportunity to LP_DEAD-mark eligible index
tuples). Back branches just get minimal hardening: we invalidate
killedItems[] at the places where the master branch gets new calls to
gistkillitems (and we invalidate curBlkno and curPageLSN on a rescan).
The test that proved corruption on master didn't result in corruption on
any stable branch, though only because, without commit 9c9ddf109, we'd
clobber curPageLSN without also updating curBlkno -- which accidentally
prevented it. Relying on gistkillitems to not LP_DEAD-mark by passing
it a curBlkno whose curPageLSN was taken from an entirely different page
seems like a very bad idea, which is why this issue is being treated as
a bug affecting all stable branches.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/CAH2-WzmwEThnQf17Ju+t0N9_KJLsEQSXzYrFnaS2=s4KnGGrqw@mail.gmail.com
Backpatch-through: 14
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/.