Horton

Re: refactoring basebackup.c

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Dipesh Pandit <dipesh.pandit@gmail.com>
Cc: Jeevan Ladhe <jeevan.ladhe@enterprisedb.com>, tushar <tushar.ahuja@enterprisedb.com>, Dmitry Dolgov <9erthalion6@gmail.com>, Mark Dilger <mark.dilger@enterprisedb.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2022-01-21T19:30:55Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Document BaseBackupSync and BaseBackupWrite wait events.

  2. Support long distance matching for zstd compression

  3. Fix possible NULL-pointer-deference in backup_compression.c.

  4. Allow parallel zstd compression when taking a base backup.

  5. Make PostgreSQL::Test::Cluster::run_log() return a useful value.

  6. Fix a few goofs in new backup compression code.

  7. Replace BASE_BACKUP COMPRESSION_LEVEL option with COMPRESSION_DETAIL.

  8. Add 'basebackup_to_shell' contrib module.

  9. Allow extensions to add new backup targets.

  10. Change HAVE_LIBLZ4 and HAVE_LIBZSTD tests to USE_LZ4 and USE_ZSTD.

  11. pg_basebackup: Clean up some bogus file extension tests.

  12. pg_basebackup: Avoid unclean failure with server-compression and -D -.

  13. Fix LZ4 tests for remaining buffer space.

  14. Add support for zstd base backup compression.

  15. pg_basebackup: Allow client-side LZ4 (de)compression.

  16. Add suport for server-side LZ4 base backup compression.

  17. Add min() and max() aggregates for xid8.

  18. Remove superfluous variable.

  19. pg_basebackup: Cleaner handling when compression is multiply specified.

  20. Allow server-side compression to be used with -Fp.

  21. pg_basebackup: Fix a couple of recently-introduced bugs.

  22. Tidy up a few cosmetic issues related to pg_basebackup.

  23. Server-side gzip compression.

  24. Unbreak pg_basebackup/t/010_pg_basebackup.pl on msys

  25. Suppress variable-set-but-not-used warning from clang 13.

  26. Extend the options of pg_basebackup to control compression

  27. Support base backup targets.

  28. Modify pg_basebackup to use a new COPY subprotocol for base backups.

  29. Document that tar archives are now properly terminated.

  30. Fix thinko in bbsink_throttle_manifest_contents.

  31. Have the server properly terminate tar archives.

  32. Minimal fix for unterminated tar archive problem.

  33. Introduce 'bbstreamer' abstraction to modularize pg_basebackup.

  34. Introduce 'bbsink' abstraction to modularize base backup code.

  35. Refactor basebackup.c's _tarWriteDir() function.

  36. Flexible options for CREATE_REPLICATION_SLOT.

  37. Flexible options for BASE_BACKUP.

On Thu, Jan 20, 2022 at 11:10 AM Robert Haas <robertmhaas@gmail.com> wrote:
> On Thu, Jan 20, 2022 at 8:00 AM Dipesh Pandit <dipesh.pandit@gmail.com> wrote:
> > Thanks for the feedback, I have incorporated the suggestions and
> > updated a new patch v2.
>
> Cool. I'll do a detailed review later, but I think this is going in a
> good direction.

Here is a more detailed review.

+    if (inflateInit2(zs, 15 + 16) != Z_OK)
+    {
+        pg_log_error("could not initialize compression library");
+        exit(1);
+
+    }

Extra blank line.

+    /* At present, we only know how to parse tar and gzip archives. */

gzip -> tar.gz. You can gzip something that is not a tar.

+     * Extract the gzip compressed archive using a gzip extractor and then
+     * forward it to next streamer.

This comment is not good. First, we're not necessarily doing it.
Second, it just describes what the code does, not why it does it.
Maybe something like "If the user requested both that the server
compress the backup and also that we extract the backup, we need to
decompress it."

+    if (server_compression != NULL)
+    {
+        if (strcmp(server_compression, "gzip") == 0)
+            server_compression_type = BACKUP_COMPRESSION_GZIP;
+        else if (strlen(server_compression) == 5 &&
+                strncmp(server_compression, "gzip", 4) == 0 &&
+                server_compression[4] >= '1' && server_compression[4] <= '9')
+        {
+            server_compression_type = BACKUP_COMPRESSION_GZIP;
+            server_compression_level = server_compression[4] - '0';
+        }
+    }
+    else
+        server_compression_type = BACKUP_COMPRESSION_NONE;

I think this is not required any more. I think probably some other
things need to be adjusted as well, based on Michael's changes and the
updates in my patch to match.

-- 
Robert Haas
EDB: http://www.enterprisedb.com