PITR bad restore possibility?
От | Rod Taylor |
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Тема | PITR bad restore possibility? |
Дата | |
Msg-id | 1114641855.14522.40.camel@home обсуждение исходный текст |
Ответы |
Re: PITR bad restore possibility?
|
Список | pgsql-hackers |
What happens if for reasons of broken tape, disk, etc. you lose some of your WAL logs which happens to correspond to the middle of the snapshot backup? The equivalent would be to: 1) Start the snapshot backup (tar) 2) Stop logging usable WAL logs (say a tape jammed or disk is corrupted) 3) Snapshot portion of the backup successfully completes Later on you try replay the above snapshot backup while cursing the partial data loss due to the tape jam or partially corrupt disk. I believe the replay would have data in the data directory which is newer and possibly contains partial transactions for data which was not replayed by the WAL logs. Would this be a usable database? How about when it eventually uses the same transaction IDs as have already been used since WAL didn't get to replay them all? If not, is there a way to find out the last WAL segment required for the snapshot backup to be usable? --
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