Re: WAL page magic number (was Re: Re: [COMMITTERS] pgsql: Make CheckRequiredParameterValues() depend upon correct)

Heikki Linnakangas wrote:
> Tom Lane wrote:
> > Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> >> Browsing the history of XLOG_PAGE_MAGIC, it used to be incremented by
> >> one whenever the format changes, at least as long as it has been been in
> >> xlog_internal.h. It started at 0xD05B in 2005, and was incremented by
> >> one by each commit till 0xD062. But then the hot standby patch bumped it
> >> to 0xD166, and on March 19th Simon changed it to 0x9002, and on March
> >> 28th to 0x9003.
> > 
> >> Is there a plan somewhere on all that, or was it just random whacking?
> > 
> > Random whacking.  Simon seems to have decided to try to make the number
> > mean something, but it never meant anything before.  It's not a version
> > number, it's a magic identifier.  We might need to avoid certain values
> > to prevent collisions with other file formats, so I'm suspicious of
> > trying to make it match up with some expectation.
> 
> Ok, for better or worse, I whacked it back to the old series.

Agreed.  Making it match the version would be odd because you then have
t bump it for every major release.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com