Re: documenting the backup manifest file format

Alvaro Herrera <alvherre@2ndquadrant.com>

From: Alvaro Herrera <alvherre@2ndquadrant.com>

To: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>

Cc: David Steele <david@pgmasters.net>, Robert Haas <robertmhaas@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, Andres Freund <andres@anarazel.de>, Amit Kapila <amit.kapila16@gmail.com>, Suraj Kharage <suraj.kharage@enterprisedb.com>, tushar <tushar.ahuja@enterprisedb.com>, Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>, Rushabh Lathia <rushabh.lathia@gmail.com>, Tels <nospam-pg-abuse@bloodgate.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Jeevan Chalke <jeevan.chalke@enterprisedb.com>, vignesh C <vignesh21@gmail.com>

Date: 2020-04-14T20:09:22Z

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 →

Try to avoid compiler warnings in optimized builds.
- 05021a2c0cd2 13.0 landed
Fix option related issues in pg_verifybackup.
- 0a89e93bfaa6 13.0 landed
Add index term for backup manifest in documentation.
- 4db819ba4039 13.0 landed
Code review for backup manifest.
- a2ac73e7be7a 13.0 landed
Document the backup manifest file format.
- 149f2ae88ab0 13.0 landed
Fix typo in pg_validatebackup documentation.
- c4f82a779d26 13.0 landed
Exclude backup_manifest file that existed in database, from BASE_BACKUP.
- 1ec50a81ec0a 13.0 landed
Msys2 tweaks for pg_validatebackup corruption test
- c3e4cbaab936 13.0 landed
Fix resource management bug with replication=database.
- 3e0d80fd8d3d 13.0 cited
Be more careful about time_t vs. pg_time_t in basebackup.c.
- db1531cae009 13.0 cited
pg_validatebackup: Fix 'make clean' to remove tmp_check.
- 9f8f881caa0f 13.0 landed
pg_validatebackup: Also use perl2host in TAP tests.
- 460314db08e8 13.0 landed
Generate backup manifests for base backups, and validate them.
- 0d8c9c1210c4 13.0 landed
Add checksum helper functions.
- c12e43a2e0d4 13.0 landed
pg_waldump: Add a --quiet option.
- ac44367efbef 13.0 landed
Catversion bump for b9b408c48724
- afb5465e0cfc 13.0 cited
pg_basebackup: Refactor code for reading COPY and tar data.
- 431ba7bebf13 13.0 landed
Use a ResourceOwner to track buffer pins in all cases.
- 3cb646264e8c 12.0 cited
Use ARMv8 CRC instructions where available.
- f044d71e331d 11.0 cited
Logical replication support for initial data copy
- 7c4f52409a8c 10.0 cited
Use Intel SSE 4.2 CRC instructions where available.
- 3dc2d62d0486 9.5.0 cited
Switch to CRC-32C in WAL and other places.
- 5028f22f6eb0 9.5.0 cited
Remove support for 64-bit CRC.
- 404bc51cde9d 9.5.0 cited
Change CRCs in WAL records from 64bit to 32bit for performance reasons.
- 21fda22ec46d 8.1.0 cited

On 2020-Apr-14, Andrew Dunstan wrote:

> OK, but I think if we're putting a timestamp string in ISO-8601 format
> in the manifest it should be in UTC / Zulu time, precisely to avoid
> these issues. If that's too much trouble then yes an epoch time will
> probably do.

The timestamp is always specified and always UTC (except the code calls
it GMT).

+   /*
+    * Convert last modification time to a string and append it to the
+    * manifest. Since it's not clear what time zone to use and since time
+    * zone definitions can change, possibly causing confusion, use GMT
+    * always.
+    */
+   appendStringInfoString(&buf, "\"Last-Modified\": \"");
+   enlargeStringInfo(&buf, 128);
+   buf.len += pg_strftime(&buf.data[buf.len], 128, "%Y-%m-%d %H:%M:%S %Z",
+                          pg_gmtime(&mtime));
+   appendStringInfoString(&buf, "\"");

I was merely saying that it's trivial to make this iso-8601 compliant as

    buf.len += pg_strftime(&buf.data[buf.len], 128, "%Y-%m-%dT%H:%M:%SZ",

ie. omit the "GMT" string and replace it with a literal Z, and remove
the space and replace it with a T.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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