Re: Online verification of checksums

Hi,

On Thu, Dec 20, 2018 at 04:19:11PM +0100, Michael Banck wrote:
> Yeah, new rebased version attached.

By the way, one thing that this patch also fixes is checksum
verification on basebackups (as pointed out the other day by my
colleague Bernd Helmele):

postgres(at)kohn:~$ initdb -k data
postgres(at)kohn:~$ pg_ctl -D data -l logfile start
waiting for server to start.... done
server started
postgres(at)kohn:~$ pg_verify_checksums -D data
pg_verify_checksums: cluster must be shut down to verify checksums
postgres(at)kohn:~$ pg_basebackup -h /tmp -D backup1
postgres(at)kohn:~$ pg_verify_checksums -D backup1
pg_verify_checksums: cluster must be shut down to verify checksums
postgres(at)kohn:~$ pg_checksums -c -D backup1
Checksum scan completed
Files scanned: 1094
Blocks scanned: 2867
Bad checksums: 0
Data checksum version: 1

Where pg_checksums has the online verification patch applied.

As I don't think many people will take down their production servers in
order to verify checksums, verifying them on basebackups looks like a
useful use-case that is currently broken with pg_verify_checksums.

Michael

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Michael Banck
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