Horton

Re: Add LZ4 compression in pg_dump

Justin Pryzby <pryzby@telsasoft.com>

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From: Justin Pryzby <pryzby@telsasoft.com>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Georgios <gkokolatos@protonmail.com>, pgsql-hackers@lists.postgresql.org, Rachel Heaton <rachelmheaton@gmail.com>
Date: 2022-03-26T23:51:34Z
Lists: pgsql-hackers 
On Sun, Mar 27, 2022 at 12:37:27AM +0100, Daniel Gustafsson wrote:
> > On 26 Mar 2022, at 17:21, Justin Pryzby <pryzby@telsasoft.com> wrote:
> 
> > I suggested off-list to add an 0099 patch to change LZ4 to the default, to
> > exercise it more on CI.
> 
> No need to change the defaults in autoconf for that.  The CFBot uses the cirrus
> file in the tree so changing what the job includes can be easily done (assuming
> the CFBot hasn't changed this recently which I think it hasn't).  I used that
> trick in the NSS patchset to add a completely new job for --with-ssl=nss beside
> the --with-ssl=openssl job.

I think you misunderstood - I'm suggesting not only to use with-lz4 (which was
always true since 93d973494), but to change pg_dump -Fc and -Fd to use LZ4 by
default (the same as I suggested for toast_compression, wal_compression, and
again in last year's patch to add zstd compression to pg_dump, for which
postgres was not ready).

@@ -781,6 +807,11 @@ main(int argc, char **argv)
                        compress.alg = COMPR_ALG_LIBZ;
                        compress.level = Z_DEFAULT_COMPRESSION;
 #endif
+
+#ifdef USE_ZSTD
+                       compress.alg = COMPR_ALG_ZSTD; // Set default for testing purposes
+                       compress.level = ZSTD_CLEVEL_DEFAULT;
+#endif

Commits

  1. Advance input pointer when LZ4 compressing data

  2. Null-terminate the output buffer of LZ4Stream_gets

  3. Rework code defining default compression for dir/custom formats in pg_dump

  4. pg_dump: Use only LZ4 frame format for compression

  5. Minor comment improvements for compress_lz4

  6. Unify buffer sizes in pg_dump compression API

  7. Improve type handling in pg_dump's compress file API

  8. Improve wording in pg_dump compression docs

  9. Fix condition in pg_dump TAP test

  10. Add LZ4 compression to pg_dump

  11. Introduce a generic pg_dump compression API

  12. Prepare pg_dump internals for additional compression methods

  13. Fix behavior with pg_restore -l and compressed dumps

  14. Add 250c8ee07ed to git-blame-ignore-revs

  15. Provide test coverage in pg_dump for default behaviors with compression

  16. Switch pg_dump to use compression specifications

  17. Refactor code parsing compression option values (-Z/--compress)

  18. meson: Add some missing env settings for tests of pg_dump and pg_verifybackup

  19. Extend TAP tests of pg_dump to test for compression with gzip

  20. Clean up some dead code in pg_dump with tar format and gzip compression

  21. Add TAP test in pg_dump with --format=tar and --compress

  22. Replace BASE_BACKUP COMPRESSION_LEVEL option with COMPRESSION_DETAIL.

  23. Refactor the pg_dump zlib code from pg_backup_custom.c to a separate file,