Checksums and full_page_writes

[Borodin Vladimir <root@xxxxxxxxxxx>]

Hi all.

I’ve read thread [0], src/backend/storage/page/README and everything I found in the documentation about checksums [1, 2] but I haven’t understood what is my risk if I enable checksums during initdb and turn off full_page_writes?

Am I right that I can get torn pages on disk in that case but I will somehow know about it during checksum checking when this page will be read from disk to shared buffers? And is there any way to recover such torn page (from replica or backup+archived logs, for example)?

[0] http://www.postgresql.org/message-id/20111217213324.GA4497@xxxxxxxxxx

[1] http://www.postgresql.org/docs/current/static/app-initdb.html#APP-INITDB-DATA-CHECKSUMS

[2] http://www.postgresql.org/docs/current/static/wal-reliability.html

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Vladimir