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c1afd175b5
Teach contrib/amcheck's bt_index_parent_check() function to take advantage of the uniqueness property of heapkeyspace indexes in support of a new verification option: non-pivot tuples (non-highkey tuples on the leaf level) can optionally be re-found using a new search for each, that starts from the root page. If a tuple cannot be re-found, report that the index is corrupt. The new "rootdescend" verification option is exhaustive, and can therefore make a call to bt_index_parent_check() take a lot longer. Re-finding tuples during verification is mostly intended as an option for backend developers, since the corruption scenarios that it alone is uniquely capable of detecting seem fairly far-fetched. For example, "rootdescend" verification is much more likely to detect corruption of the least significant byte of a key from a pivot tuple in the root page of a B-Tree that already has at least three levels. Typically, only a few tuples on a cousin leaf page are at risk of "getting overlooked" by index scans in this scenario. The corrupt key in the root page is only slightly corrupt: corrupt enough to give wrong answers to some queries, and yet not corrupt enough to allow the problem to be detected without verifying agreement between the leaf page and the root page, skipping at least one internal page level. The existing bt_index_parent_check() checks never cross more than a single level. Author: Peter Geoghegan Reviewed-By: Heikki Linnakangas Discussion: https://postgr.es/m/CAH2-Wz=yTWnVu+HeHGKb2AGiADL9eprn-cKYAto4MkKOuiGtRQ@mail.gmail.com |
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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/.