Horton

Re: backup manifests

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: David Steele <david@pgmasters.net>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2019-09-25T12:46:54Z
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. Try to avoid compiler warnings in optimized builds.

  2. Fix option related issues in pg_verifybackup.

  3. Add index term for backup manifest in documentation.

  4. Code review for backup manifest.

  5. Document the backup manifest file format.

  6. Fix typo in pg_validatebackup documentation.

  7. Exclude backup_manifest file that existed in database, from BASE_BACKUP.

  8. Msys2 tweaks for pg_validatebackup corruption test

  9. Fix resource management bug with replication=database.

  10. Be more careful about time_t vs. pg_time_t in basebackup.c.

  11. pg_validatebackup: Fix 'make clean' to remove tmp_check.

  12. pg_validatebackup: Also use perl2host in TAP tests.

  13. Generate backup manifests for base backups, and validate them.

  14. Add checksum helper functions.

  15. pg_waldump: Add a --quiet option.

  16. Catversion bump for b9b408c48724

  17. pg_basebackup: Refactor code for reading COPY and tar data.

  18. Use a ResourceOwner to track buffer pins in all cases.

  19. Use ARMv8 CRC instructions where available.

  20. Logical replication support for initial data copy

  21. Use Intel SSE 4.2 CRC instructions where available.

  22. Switch to CRC-32C in WAL and other places.

  23. Remove support for 64-bit CRC.

  24. Change CRCs in WAL records from 64bit to 32bit for performance reasons.

On Sat, Sep 21, 2019 at 12:25 AM Robert Haas <robertmhaas@gmail.com> wrote:
>
Some comments:

Manifest file will be in plain text format even if compression is
specified, should we compress it?
May be this is intended, just raised the point to make sure that it is intended.
+static void
+ReceiveBackupManifestChunk(size_t r, char *copybuf, void *callback_data)
+{
+ WriteManifestState *state = callback_data;
+
+ if (fwrite(copybuf, r, 1, state->file) != 1)
+ {
+ pg_log_error("could not write to file \"%s\": %m", state->filename);
+ exit(1);
+ }
+}

WALfile.done file gets added but wal file information is not included
in the manifest file, should we include WAL file also?
@@ -599,16 +618,20 @@ perform_base_backup(basebackup_options *opt)
  (errcode_for_file_access(),
  errmsg("could not stat file \"%s\": %m", pathbuf)));

- sendFile(pathbuf, pathbuf, &statbuf, false, InvalidOid);
+ sendFile(pathbuf, pathbuf, &statbuf, false, InvalidOid, manifest,
+ NULL);

  /* unconditionally mark file as archived */
  StatusFilePath(pathbuf, fname, ".done");
- sendFileWithContent(pathbuf, "");
+ sendFileWithContent(pathbuf, "", manifest);

Should we add an option to make manifest generation configurable to
reduce overhead during backup?

Manifest file does not include directory information, should we include it?

There is one warning:
In file included from ../../../src/include/fe_utils/string_utils.h:20:0,
                 from pg_basebackup.c:34:
pg_basebackup.c: In function ‘ReceiveTarFile’:
../../../src/interfaces/libpq/pqexpbuffer.h:60:9: warning: the
comparison will always evaluate as ‘false’ for the address of ‘buf’
will never be NULL [-Waddress]
  ((str) == NULL || (str)->maxlen == 0)
         ^
pg_basebackup.c:1203:7: note: in expansion of macro ‘PQExpBufferBroken’
   if (PQExpBufferBroken(&buf))

pg_gmtime can fail in case of malloc failure:
+ /*
+ * Convert time to a string. Since it's not clear what time zone to use
+ * and since time zone definitions can change, possibly causing confusion,
+ * use GMT always.
+ */
+ pg_strftime(timebuf, sizeof(timebuf), "%Y-%m-%d %H:%M:%S %Z",
+ pg_gmtime(&mtime));

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com