Postgres restart in the middle of exclusive backup and the presence of backup_label file - Mailing list pgsql-hackers

From SATYANARAYANA NARLAPURAM
Subject Postgres restart in the middle of exclusive backup and the presence of backup_label file
Date
Msg-id CAHg+QDfiM+WU61tF6=nPZocMZvHDzCK47Kneyb0ZRULYzV5sKQ@mail.gmail.com
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Responses Re: Postgres restart in the middle of exclusive backup and the presence of backup_label file
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Hi Hackers,

While an exclusive backup is in progress if Postgres restarts, postgres runs the recovery from the checkpoint identified by the label file instead of the control file. This can cause long recovery or even sometimes fail to recover as the WAL records corresponding to that checkpoint location are removed. I can write a layer in my control plane to remove the backup_label file when I know the server is not in restore from the base backup but I don't see a reason why everyone has to repeat this step. Am I missing something?

If there are no standby.signal or recovery.signal, what is the use case of honoring backup_label file? Even when they exist, for a long running recovery, should we honor the backup_label file as the majority of the WAL already applied? It does slow down the recovery on restart right as it has to start all the way from the beginning?

Thanks,
Satya

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