Re: WAL page magic number (was Re: Re: [COMMITTERS] pgsql: Make CheckRequiredParameterValues() depend upon correct)
Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@commandprompt.com>, Robert Haas <robertmhaas@gmail.com>, Simon Riggs <simon@2ndquadrant.com>, pgsql-hackers@postgresql.org
Date: 2010-04-28T16:11:52Z
Lists: pgsql-hackers
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. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com