postgresql.git/doc/src/sgml/installation.sgml, branch master

Revert "Make PL/Tcl require Tcl 8.6 or later"

2026-07-16T10:38:37Z

This reverts commit b6d3ccf2f5f1a179e25e277bae3f432cc084ce58. macOS still ships with Tcl 8.5.

Require ICU 55 or later

2026-07-16T10:03:05Z

Support for older versions is removed. Since we no longer support RHEL 7, we don't need to support these old versions anymore. This allows a fair amount of code cleanup, including some code blocks that specifically catered to old versions that probably received very little actual testing and use. Reviewed-by: Jelte Fennema-Nio Discussion: https://www.postgresql.org/message-id/flat/CA+hUKGL7trhWiJ4qxpksBztMMTWDyPnP1QN+Lq341V7QL775DA@mail.gmail.com

Make PL/Tcl require Tcl 8.6 or later

2026-07-16T10:03:05Z

Support for Tcl 8.5 and 8.4 is removed. Since we no longer support RHEL 7, we don't need to support these old versions anymore. This allows some small amount of code cleanup. Reviewed-by: Jelte Fennema-Nio Discussion: https://www.postgresql.org/message-id/flat/CA+hUKGL7trhWiJ4qxpksBztMMTWDyPnP1QN+Lq341V7QL775DA@mail.gmail.com

Raise requirement to Visual Studio 2022

2026-07-16T10:03:05Z

The use of _Generic from commit "Replace __builtin_types_compatible_p with _Generic" causes compiler errors from VS 2019. Apparently, that compiler is just broken for that (even though it appears to support _Generic in general, for example in commit 59c2f03d1ec). Per discussion, just drop support for VS 2019 and require at least VS 2022. This just updates the documentation about that. In passing, some information about VS 2026 is added. Reviewed-by: Jelte Fennema-Nio Discussion: https://www.postgresql.org/message-id/flat/CA+hUKGL7trhWiJ4qxpksBztMMTWDyPnP1QN+Lq341V7QL775DA@mail.gmail.com

Revert "Change default value of default_toast_compression to "lz4""

2026-03-04T23:25:35Z

This reverts commit 7c1849311e49, due to the fact that more than 60% of the buildfarm members do not have lz4 installed. As we are in the last commit fest of the development cycle, and that it could take a couple of weeks to stabilize things, this change is reverted for now. This commit will be reworked in a lighter version, as default_toast_compression's default can be changed to "lz4" without the switch from --with-lz4 to --without-lz4. This approach will keep the buildfarm at bay, and still allow builds to take advantage of LZ4 in TOAST by default, as long as the code is compiled with LZ4 support. A harder requirement based on LZ4 should be achievable at some point, but it is going to require some work from the buildfarm owners first. Perhaps this part could be revisited at the beginning of the next development cycle. Discussion: https://postgr.es/m/CAOYmi+meTT0NbLbnVqOJD5OKwCtHL86PQ+RZZTrn6umfmHyWaw@mail.gmail.com

Change default value of default_toast_compression to "lz4", when available

2026-03-04T04:05:31Z

The default value for default_toast_compression was "pglz". The main reason for this choice is that this option is always available, pglz code being embedded in Postgres. However, it is known that LZ4 is more efficient than pglz: less CPU required, more compression on average. As of this commit, the default value of default_toast_compression becomes "lz4", if available. By switching to LZ4 as the default, users should see natural speedups on TOAST data reads and/or writes. Support for LZ4 in TOAST compression was added in Postgres v14, or 5 releases ago. This should be long enough to consider this feature as stable. --with-lz4 is removed, replaced by a --without-lz4 to disable LZ4 in the builds on an option-basis, following a practice similar to readline or ICU. References to --with-lz4 are removed from the documentation. While at it, quotes are removed from default_toast_compression in postgresql.conf.sample. Quotes are not required in this case. The in-place value replacement done by initdb if the build supports LZ4 would not use them in the postgresql.conf file added to a freshly-initialized cluster. For the reference, a similar switch has been done with ICU in fcb21b3acdcb. Some of the changes done in this commit are consistent with that. Note: this is going to create some disturbance in the buildfarm, in environments where lz4 is not installed. Author: Euler Taveira Reviewed-by: Peter Eisentraut Reviewed-by: Aleksander Alekseev Discussion: https://posgr.es/m/435df33a-129e-4f0c-a803-f3935c5a5ecb@eisentraut.org

Restore AIX support.

2026-02-23T18:34:22Z

The concerns that led us to remove AIX support in commit 0b16bb877 have now been alleviated: 1. IBM has stepped forward to provide support, including buildfarm animal(s). 2. AIX 7.2 and later seem to be fine with large pg_attribute_aligned requirements. Since 7.1 is now EOL anyway, we can just cease to support it. 3. Tossing xlc support overboard seems okay as well. It's a bit sad to drop one of the few remaining non-gcc-alike compilers, but working around xlc's bugs and idiosyncrasies doesn't seem justified by the theoretical portability benefits. 4. Likewise, we can stop supporting 32-bit AIX builds. This is not so much about whether we could build such executables as that they're too much of a pain to manage in the field, due to limited address space available for dynamic library loading. 5. We hit on a way to manage catalog column alignment that doesn't require continuing developer effort (see commit ecae09725). Hence, this commit reverts 0b16bb877 and some follow-on commits such as e6bb491bf, except for not putting back XLC support nor the changes related to catalog column alignment. Some other notable changes from the way things were in v16: Prefer unnamed POSIX semaphores on AIX, rather than the default choice of SysV semaphores. Include /opt/freeware/lib in -Wl,-blibpath, even when it is not mentioned anywhere in LDFLAGS. Remove platform-specific adjustment of MEMSET_LOOP_LIMIT; maybe that's still the right thing, but it really ought to be re-tested. Silence compiler warnings related to getpeereid(), wcstombs_l(), and PAM conversation procs. Accept "libpythonXXX.a" as an okay name for the Python shared library (but only on AIX!). Author: Aditya Kamath Author: Srirama Kucherlapati Co-authored-by: Peter Eisentraut Reviewed-by: Tom Lane Discussion: https://postgr.es/m/CY5PR11MB63928CC05906F27FB10D74D0FD322@CY5PR11MB6392.namprd11.prod.outlook.com

meson: allow disabling building/installation of static libraries.

2026-02-23T15:45:40Z

We now support the common meson option -Ddefault_library, with values 'both' (the default), 'shared' (install only shared libraries), and 'static' (install only static libraries). The 'static' choice doesn't actually work, since psql and other programs insist on linking to the shared version of libpq, but it's there pro-forma. It could be built out if we really wanted, but since we have never supported the equivalent in the autoconf build system, there doesn't appear to be an urgent need. With an eye to re-supporting AIX, the internal implementation distinguishes whether to install libpgport.a and other static-only libraries from whether to build/install the static variant of libraries that we can build both ways. This detail isn't exposed as a meson option, though it could be if there's demand. The Cirrus CI task SanityCheck now uses -Ddefault_library=shared to save a little bit of build time (and to test this option). Author: Peter Eisentraut Reviewed-by: Andres Freund Reviewed-by: Tom Lane Discussion: https://postgr.es/m/e8aa97db-872b-4087-b073-f296baae948d@eisentraut.org

MSVC: Support building for AArch64.

2026-01-07T19:42:57Z

This commit does the following to get tests passing for MSVC/AArch64: * Implements spin_delay() with an ISB instruction (like we do for gcc/clang on AArch64). * Sets USE_ARMV8_CRC32C unconditionally. Vendor-supported versions of Windows for AArch64 require at least ARMv8.1, which is where CRC extension support became mandatory. * Implements S_UNLOCK() with _InterlockedExchange(). The existing implementation for MSVC uses _ReadWriteBarrier() (a compiler barrier), which is insufficient for this purpose on non-TSO architectures. There are likely other changes required to take full advantage of the hardware (e.g., atomics/arch-arm.h, simd.h, pg_popcount_aarch64.c), but those can be dealt with later. Author: Niyas Sait Co-authored-by: Greg Burd Co-authored-by: Dave Cramer Reviewed-by: Michael Paquier Reviewed-by: John Naylor Reviewed-by: Peter Eisentraut Reviewed-by: Andres Freund Reviewed-by: Thomas Munro Tested-by: Andrew Dunstan Discussion: https://postgr.es/m/A6152C7C-F5E3-4958-8F8E-7692D259FF2F%40greg.burd.me Discussion: https://postgr.es/m/CAFPTBD-74%2BAEuN9n7caJ0YUnW5A0r-KBX8rYoEJWqFPgLKpzdg%40mail.gmail.com

doc: Assorted documentation improvements

2025-11-20T14:04:41Z

A set of wording improvements and spelling fixes. Author: Oleg Sibiryakov Reviewed-by: Daniel Gustafsson Reviewed-by: Peter Eisentraut Discussion: https://postgr.es/m/e62bedb5-c26f-4d37-b4ed-ce9b55f1e980@postgrespro.ru