932f9fb504
pg_test_fsync has always opened files using the text mode on Windows, as this is the default mode used if not enforced by _setmode(). This fixes a failure when running pg_test_fsync down to 12 because O_DSYNC and the text mode are not able to work together nicely. We fixed the handling of O_DSYNC in 12~ for the tool by switching to the concurrent-safe version of fopen() in src/port/ with 0ba06e0. And 40cfe86, by enforcing the text mode for compatibility reasons if O_TEXT or O_BINARY are not specified by the caller, broke pg_test_fsync. For all versions, this avoids any translation overhead, and pg_test_fsync should test binary writes, so it is a gain in all cases. Note that O_DSYNC is still not handled correctly in ~11, leading to pg_test_fsync to show insanely high numbers for open_datasync() (using this property it is easy to notice that the binary mode is much faster). This would require a backpatch of 0ba06e0 and 40cfe86, which could potentially break existing applications, so this is left out. There are no TAP tests for this tool yet, so I have checked all builds manually using MSVC. We could invent a new option to run a single transaction instead of using a duration of 1s to make the tests a maximum short, but this is left as future work. Thanks to Bruce Momjian for the discussion. Reported-by: Jeff Janes Author: Michael Paquier Discussion: https://postgr.es/m/16526-279ded30a230d275@postgresql.org Backpatch-through: 9.5
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/.