Horton

Re: Direct I/O

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Andrew Dunstan <andrew@dunslane.net>, Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>, Christoph Berg <myon@debian.org>, mikael.kjellstrom@gmail.com, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2023-04-15T22:10:59Z
Lists: pgsql-hackers 
Thomas Munro <thomas.munro@gmail.com> writes:
> Full GCC support including stack objects actually began in 4.6, it
> seems.

Hmm.  The oldest gcc versions remaining in the buildfarm seem to be

 curculio      | configure: using compiler=gcc (GCC) 4.2.1 20070719 
 frogfish      | configure: using compiler=gcc (Debian 4.6.3-14) 4.6.3
 lapwing       | configure: using compiler=gcc (Debian 4.7.2-5) 4.7.2
 skate         | configure: using compiler=gcc-4.7 (Debian 4.7.2-5) 4.7.2
 snapper       | configure: using compiler=gcc-4.7 (Debian 4.7.2-5) 4.7.2
 buri          | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
 chub          | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
 dhole         | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
 mantid        | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
 prion         | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28)
 rhinoceros    | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
 siskin        | configure: using compiler=gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)
 shelduck      | configure: using compiler=gcc (SUSE Linux) 4.8.5
 topminnow     | configure: using compiler=gcc (Debian 4.9.2-10+deb8u1) 4.9.2

so curculio should be the only one that's at risk here.
Maybe just upgrading it is the right answer.

			regards, tom lane

Commits

  1. Rename hook functions for debug_io_direct to match variable name.

  2. Rename io_direct to debug_io_direct.

  3. Skip the 004_io_direct.pl test if a pre-flight check fails.

  4. Use higher wal_level for 004_io_direct.pl.

  5. Skip \password TAP test on old IPC::Run versions

  6. Add io_direct setting (developer-only).

  7. Introduce PG_IO_ALIGN_SIZE and align all I/O buffers.

  8. Add palloc_aligned() to allow aligned memory allocations

  9. initdb: When running CREATE DATABASE, use STRATEGY = WAL_COPY.