Re: replication between mysql 3.23 and postgresql 7.2.4?

A long time ago, in a galaxy far, far away, k_b0000@yahoo.se (k b) wrote:
> Hello.
>
> I have a slightly off topic question.
> Is it possible to set up replication between a mysql
> 3.23.56 server and a postgresql 7.2.4 server without
> any extra software in between?
>
> i am primarily interested in replication from the
> mysql server to the postgresql server, but two way
> replication might be needed later on.
>
> is it possible?
> where can i find more information?

You might look at how MySQL's "native" replication schemes are
implemented, and see if there is some way to adapt them to generate
SQL statements that could be injected into a PostgreSQL instance.

But what this amounts to is "rolling your own solution."

It also strikes me as a good instance of a "fool's errand," as the
semantics of the systems are so strikingly different that you'll find
that if you _do_ implement some form of replication, it won't work
nearly as well as you would hope or need.

The comments comparing MySQL with Oracle seem pretty appropriate
<http://sql-info.de/mysql/vs/mysql-oracle.html>

Notably:

  "If you find your application works as equally well on Oracle as it
  does on MySQL, then you are vastly underutilising Oracle and
  probably paying for it as well."

In the case of PostgreSQL, you may not be paying anything for it, but
you certainly won't be getting any benefit out of it if you use it
exactly the same as you use MySQL.

And why PostgreSQL 7.2.4?  That's a fairly ancient version, now.  If
you're prepared to do something as experimental as building a two-way
replication system between MySQL and PostgreSQL, jumping straight to
8.0 won't introduce any risks that would be noticeable in comparison
to the ones you already face.  The 'conservative' approach would be to
use 7.4.3, anyways.

You might as well not bother; that will involve a whole lot less
effort, and leave you less disgruntled at the end of the process.
--
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