Greetings,
* Meera Nair (mnair@xxxxxxxxxxxxx) wrote:
> The backups we ran were all exclusive backups.
You should not use exclusive backups. They've been deprecated for a
long, long time and have been removed in the most recent version of PG.
You really should not be trying to build your own tooling for this.
Please, use an existing tool where the authors have already worked
through how all of this works and understand how BACKUP_END works and
how to reliably perform a backup and restore of PG. Despite the
documentation seeming to imply that it's trivial to do this on your own,
it really isn't.
> pg_start_backup('label') returned 000000040000000200000041. Then we made a copy of data directory .
> Then pg_stop_backup() was executed and it returned 000000040000000200000046.
I'm really not sure what you're doing exactly, but it sure looks like
the BACKUP_END in the 46 WAL file is associated with the .backup file
for the backup started in the 45 segment. You have this file:
000000040000000200000045.00005AE0.backup
and then this is what you reported from the 46 file:
rmgr: XLOG len (rec/tot): 34/ 34, tx: 0, lsn: 2/46000110, prev 2/46000098, desc: BACKUP_END 2/45005AE0
Note that the 'BACKUP_END' data content there is the starting point of
the backup for which that is the BACKUP_END for- 2/45005AE0. That
matches with a backup being started in the 45 file and matches the
start time of the .backup file that you have in the archive. That's why
the restore of the backup started in the 41 segment isn't picking up on
the BACKUP_END in the 46 file as being the one matching that backup-
because that's from some other backup.
> To verify the copied data is restorable, we stopped server. Renamed data and archive log directories.
> Replaced it with data and archive log directories copied earlier. In archive log directory logs from 41 to 49 is present.
The pg_wal dir can and should be empty at the start.
> Created recovery.signal and added restore_command to postgresql.conf file. And tried to start server. this failed with error in previous mail.
The restore_command should be copying WAL files from the location where
they were stored by the archive_command.
Thanks,
Stephen
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