Re: Replication and coding good practices

On Sun, 2009-06-28 at 09:01 -0700, David Fetter wrote:
> > Are there any rules of thumb to consider for making an application
> > easier to work with a "general" replication solution?
> >
> > The applications I mostly deal with are e-commerce sites.
>
> It really depends on what replication solution you choose, along with
> the environment you're deploying into.

... and why you need replication. Reliability/Availability? Data storage
redundancy? Performance? And if performance, read-mostly performance or
write-heavy performance?

> That said, I've noticed that the things that are generally good
> practice help you even more when you're doing replication.
>
> Practices I've seen help directly:
>
> * Separate read users and code from write users and code.
>
> * Separate DDL from both of the above.
>
> * Make DDL changes part of your deployment process and only allow them
>   in files which track in your SCM system.

Version your schema, storing the schema version in a 1-row table or even
as a stable function. This makes it much easier for deployment tools or
staff to easily see what needs to be done to get the schema and app to
the latest version - there's no "what the hell is the current state of
this thing, anyway?" to worry about.

--
Craig Ringer