Re: pgsql: Bootstrap WAL to begin at segment logid=0 logseg=1 (000000010000

Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
> On 03.11.2010 11:34, Greg Stark wrote:
>> I'm actually not nearly so sanguine about this not affecting existing
>> installations. It means, for example, that anyone who has written
>> monitoring scripts that watch the wal position will see behaviour
>> they're not familiar with.

> You mean, they will see an unfamiliar wal position right after initdb? I
> guess, but who runs monitoring scripts on a freshly initdb'd database
> before doing anything on it?

The WAL position immediately after initdb is unspecified, and definitely
NOT 0/0, in any case. From this perspective initdb will merely seem to
have emitted more WAL than it used to.

A possibly more realistic objection is that a slave freshly initdb'd
with 9.0.2 might have trouble syncing up with a master using 9.0.1,
if the master is so new it hasn't chewed a segment's worth of WAL yet.
Not sure if this is actually a problem.

regards, tom lane