Horton

Re: pg_dump versus ancient server versions

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Robert Haas <robertmhaas@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-10-25T17:17:20Z
Lists: pgsql-hackers 
Hi,

On 2021-10-25 12:43:15 -0400, Tom Lane wrote:
> Agreed, that might be too much work compared to the value.  But if we're
> to be selective about support for this, I'm unclear on how we decide
> which platforms are supported --- and, more importantly, how we keep
> that list up to date over time.

I honestly think that if we just test on linux with a single distribution,
we're already covering most of the benefit. From memory there have been two
rough classes of doesn't-build-anymore:

1) New optimizations / warnings. At least between gcc and clang, within a year
   or two, most of the issues end up being visible with the other compiler
   too. These aren't particularly distribution / OS specific.

2) Library dependencies cause problems, like the ssl detection mentioned
   elsewhere in this thread. This is also not that OS dependent. It's also not
   that clear that we can do something about the issues with a reasonable
   amount of effort in all cases. It's easy enough if it's just a minor
   configure fix, but we'd not want to backpatch larger SSL changes or such.


Maybe there's also a case for building older releases with msvc, but that
seems like a pain due to the msvc project generation needing to support a
specific version of msvc.

Greetings,

Andres Freund

Commits

  1. Remove psql support for server versions preceding 9.2.

  2. Clean up some more freshly-dead code in pg_dump and pg_upgrade.

  3. Remove pg_dump's --no-synchronized-snapshots switch.

  4. Remove pg_upgrade support for upgrading from pre-9.2 servers.

  5. Remove pg_dump/pg_dumpall support for dumping from pre-9.2 servers.

  6. Suppress -Warray-bounds warning in 9.2's xlog.c.

  7. Suppress -Wformat-overflow warnings in 9.2's xml.c.

  8. Disable -Wsometimes-uninitialized warnings in the 9.2 branch.

  9. Fix function return type confusion

  10. Fix compiler warning

  11. Silence another gcc 11 warning.

  12. Suppress uninitialized-variable warning in guc.c.

  13. Suppress -Warray-parameter warnings in pgcrypto/sha2.c.

  14. Reformat imath.c macro to remove -Wmisleading-indentation warnings.

  15. Clean up compilation warnings coming from PL/Perl with clang-12~

  16. Make ecpg's rjulmdy() and rmdyjul() agree with their declarations.

  17. Use -Wno-format-truncation and -Wno-stringop-truncation, if available.

  18. Make pg_upgrade's test.sh less chatty.

  19. Add checks for valid multibyte character length in UtfToLocal, LocalToUtf.

  20. Use return instead of exit() in configure

  21. Add support for Visual Studio 2019 in build scripts