6a97ca3128
By default VACUUM will skip pages that it can't immediately get exclusive access to, which means that even activities as harmless and unpredictable as checkpoint buffer writes might prevent a page from being processed. Ordinarily this is no big deal, but we have a small number of test cases that examine the results of VACUUM's processing and therefore will fail if the page of interest is skipped. This seems to be the explanation for some rare buildfarm failures. To fix, add the DISABLE_PAGE_SKIPPING option to the VACUUM commands in tests where this could be an issue. In passing, remove a duplicated query in pageinspect/sql/page.sql. Back-patch as necessary (some of these cases are as old as v10). Discussion: https://postgr.es/m/413923.1611006484@sss.pgh.pa.us
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/.