Re: Limitations of PostgreSQL

On Wed, 2005-10-12 at 16:16, Chris Travers wrote:
> Denis G Dudhia wrote:
>
> > Hello There...
> >
> > I am new to PostgreSQL.
> >
> > I usually check out negative sides of any software or system, before
> > implementing it or using it.
> >
> Compared to MySQL, I can't think of any downsides. All relevant
> usability issues have been solved, though there are some functions like
> INTERVAL that are not supported (see my migration guide at
> http://www.metatrontech.com/wpapers/)

What, exactly, is the interval function in MySQL? IS that one that
creates a sequence of numbers or whatnot? If so, there is an equivalent
in 8.0 now. By the way, interval is a SQL reserved keyword, so it's
surprising MySQL would choose to name a function after it.

Thought I'd comment on this.

According to the author of the innodb engine, innodb uses MVCC.
OTOH, I consider innodb to be broken in production, due to issues with
constant growth and no way to reclaim the lost space.

This means that vacuuming, a minor annoyance in PostgreSQL, is a major
issue for 24/7 mysql databases running on innodb, where they must be
shut down and restarted to clear up the unused space in the innodb
tablespace.

About Mammoth, I'm pretty sure that when you purchase a support contract
you get a copy of the source code.

> Multimaster async replication w/updates is a pain at the moment and
> mostly a set of kludges.

There really are too many use cases for there to be a "simple"
resolution to the problems presented by multi-master replication. It's
a complex problem that creates more complex problems as you attempt to
solve it.

> I am not aware of any good sync. replication solutions for PostgreSQL at
> the moment.

pgpool does a good job. Many folks miss the fact that it can do
replication as well as load balancing. pgcluster uses parts of pgpool
to do its clustering as well. They are, however, statement level, not
log level.

> Does not have full XA support at the moment (does have TPC).

I'd point out here that MySQL's XA support is quite primitive, and only
useful for a fairly smaller number of cases.

> May not be the best choice on Windows for production use, though for
> development, it should be adequate.

Agreed...