Re: incorrect handling of the timeout in pg_receivexlog

On 07.02.2012 16:55, Tom Lane wrote:
> (The integer vs float TimestampTz issue is a kind of portability
> problem, but we've already bought into the assumption that sender and
> receiver must be built with the same choice, no?)

Hmm, true. In hindsight, I think that was a bad choice, but it's a bit
late to change that. pg_basebackup doesn't otherwise care about the
integer/float timestamps, but it does send a timestamp back to the
server. You won't be able to actually start up the database if the
config options don't match, but I think it would be good if
pg_basebackup still worked across platforms and versions. For example,
you might have a central backup server that calls pg_basebackup on
several database servers, running on different platforms.

In 9.0, the only field in the protocol that depends on timestamp format
is WalDataMessageHeader->sendTime. That goes from server to client, and
pg_basebackup/pg_receivexlog don't care about that. In 9.1 we introduced
StandbyReplyMessage->sendTime, which is sent from client to server, but
looking at the code it looks like the server doesn't use it for
anything. In 9.2, we added WalSndrMessage->sendTime, which is used by a
standby server to calculate how far behind the standby is.

I'm tempted to just change all of those TimestampTz fields to something
that's independent of integer/float timestamp setting, in 9.2. At a
quick glance, it seems that it wouldn't break anything.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com