Re: Replication documentation addition

Hello Bruce,

Bruce Momjian wrote:
> Here is a new replication documentation section I want to add for 8.2:
>
> ftp://momjian.us/pub/postgresql/mypatches/replication
>
> Comments welcomed.

Thank you, that sounds good. It's targeted to production use and
currently available solutions, which makes sense in the official manual.

You are explaining the sync vs. async categorization, but I sort of
asked myself where the explanation of single vs multi-master has gone. I
then realized, that you are talking about read-only and a "read/write
mix of servers". Then again, you are mentioning 'Multi-Master
Replication' as one type of replication solutions. I think we should be
consistent in our naming. As Single- and Multi-Master are the more
common terms among database replication experts, I'd recommend to use
them and explain what they mean instead of introducing new names.

Along with that, I'd argue that this Single- or Multi-Master is a
categorization as Sync vs Async. In that sense, the last chapter should
probably be named 'Distributed-Shared-Memory Replication' or something
like that instead of 'Multi-Master Replication', because as we know,
there are several ways of doing Multi-Master Replication (Slony-II /
Postgres-R, Distributed Shared Memory, 2PC in application code or the
above mentioned 'Query Broadcast Replication', which would fall into a
Multi-Master Replication model as well)

Also in the last chapter, instead of just saying that "PostgreSQL does
not offer this type of replication", we could probably say that
different projects are trying to come up with better replication
solutions. And there are several proprietary products based on
PostgreSQL which do solve some kinds of Multi-Master Replication. Not
that I want to advertise for any of them, but it just sounds better than
the current "no, we don't offer that".

As this documentation mainly covers production-quality solutions (which
is absolutely perfect), can we document the status of current projects
somewhere, probably in a wiki? Or at least mention them somewhere and
point to their websites? It would help to get rid of all those rumors
and uncertainties. Or are those intentional?

Just my two cents.

Regards

Markus