Re: Streaming replication status

On Fri, Jan 8, 2010 at 9:16 PM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:

> * We still have a related issue, though: if standby is configured to
> archive to the same location as master (as it always is on my laptop,
> where I use the postgresql.conf of the master unmodified in the server),
> right after failover the standby server will try to archive all the old
> WAL files that were streamed from the master; but they exist already in
> the archive, as the master archived them already. I'm not sure if this
> is a pilot error, or if we should do something in the server to tell
> apart WAL segments streamed from master and those generated in the
> standby server after failover. Maybe we should immediately create a
> .done file for every file received from master?

How do we know the master has finished archiving them? If the master
crashes suddenly and you fail over couldn't it have failed to archive
segments that have been received by the standby via streaming
replication?

> * Need to add comments somewhere to note that ReadRecord depends on the
> fact that a WAL record is always send as whole, never split across two
> messages.

What happens in the case of the very large records Tom was describing
recently. If the entire record doesn't fit in a WAL segment is it the
whole record or the partial record with the continuation bit that
needs to fit in a message?

--
greg