Re: Online base backup from the hot-standby

> Is there any way to tell from the WAL segments if they contain the full
> page data? If so could you verify this on the second slave when it is
> brought up? Or can you track this on the first slave and produce an
> error in either pg_start_backup or pg_stop_backup()

Sure.
I will make a patch with the way to tell from the WAL segments if they
contain the full page data.

> I see in xlog.h XLR_BKP_REMOVABLE, the comment above it says that this
> flag is used to indicate that the archiver can compress the full page
> blocks to non-full page blocks. I am not familiar with where in the code
> this actually happens but will this cause issues if the first standby is
> processing WAL files from the archive?

I confirmed the flag in xlog.c, so I seemed to only insert it in
XLogInsert(). I consider whether it is available.

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Jun Ishizuka
NTT Software Corporation
TEL：045-317-7018
E-Mail: ishizuka(dot)jun(at)po(dot)ntts(dot)co(dot)jp
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