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Avoid "right sibling's left-link doesn't match" errors when vacuuming a corrupt nbtree index. Just LOG the issue and press on. That way VACUUM will have a decent chance of finishing off all required processing for the index (and for the table as a whole). This error was seen in the field from time to time (it's more than a theoretical risk), so giving VACUUM the ability to press on like this has real value. Nothing short of a REINDEX is expected to fix the underlying index corruption, so giving up (by throwing an error) risks making a bad situation far worse. Anything that blocks forward progress by VACUUM like this might go unnoticed for a long time. This could eventually lead to a wraparound/xidStopLimit outage. Note that _bt_unlink_halfdead_page() has always been able to bail on page deletion when the target page's left sibling page was in an inconsistent state. It now does the same thing (returns false to back out of the second phase of deletion) when it notices sibling link corruption in the target page's right sibling page. This is similar to the work from commit 5b861baa (later backpatched as commit 43e409ce), which taught nbtree to press on with vacuuming an index when page deletion fails to "re-find" a downlink in the target page's parent page. The "re-find" check seems to make VACUUM bail on page deletion more often in practice, but there is no reason to take any chances here. Author: Peter Geoghegan <pg@bowt.ie> Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi> Discussion: https://postgr.es/m/CAH2-Wzko2q2kP1+UvgJyP9g0mF4hopK0NtQZcxwvMv9_ytGhkQ@mail.gmail.com Backpatch: 11- (all supported versions).
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/.