mirror of
https://git.postgresql.org/git/postgresql.git
synced 2026-02-22 22:37:01 +08:00
a712487087
Unfortunately the segment size checks from 72a98a6395 had the negative side-effect of breaking a corner case in mdsync(): When processing a fsync request for a truncated away segment mdsync() could fail with "could not fsync file" (if previous segment < RELSEG_SIZE) because _mdfd_getseg() now wouldn't return the relevant segment anymore. The cleanest fix seems to be to allow the caller of _mdfd_getseg() to specify whether checks for RELSEG_SIZE are performed. To allow doing so, change the ExtensionBehavior enum into a bitmask. Besides allowing for the addition of EXTENSION_DONT_CHECK_SIZE, this makes for a nicer implementation of EXTENSION_REALLY_RETURN_NULL. Besides mdsync() the only callsite that should change behaviour due to this is mdprefetch() which now doesn't create segments anymore, even in recovery. Given the uses of mdprefetch() that seems better. Reported-By: Thom Brown Discussion: CAA-aLv72QazLvPdKZYpVn4a_Eh+i4_cxuB03k+iCuZM_xjc+6Q@mail.gmail.com
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: http://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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.