On Wed, 2006-04-12 at 11:28, Ian Harding wrote:
> This is interesting.
>
> http://www-128.ibm.com/developerworks/db2/library/techarticle/dm-0603wasserman2/
>
> There are a few bugs
>
> 1. In the graphic overview PostgreSQL == Progres
> 2. In description of PostgreSQL database cluster, "After
> initialization, a database cluster contains a database called
> postgres, which is a default database used by utilities, users and
> third party applications. " That doesn't seem to be necessarily true.
> I don't have that database....
> 3. He misses the fact that some configuration options can be set
> interactively via SET
> 4. "The VACUUM command must be run on a regular basis to recover disk
> space occupied by updated or deleted rows and to update data
> statistics used by the PostgreSQL query planner. " with no mention of
> autovacuum. He is talking about 8.1.
>
> Every time I learn about a big commercial database I am amazed at how
> much 'bigger' and more complicated than PostgreSQL they are - I guess
> they have to be for their intended use - and how similar to PostgreSQL
> they are in actual function.
Actually, after reading that page, I'm don't think DB2 came off as being
much better than PostgreSQL.
The postgres database is new to 8.1, I believe. I think it was as much
as anything to stop the bothersome "database postgres does not exist"
error messages a newbie would get when starting out.
In addition to no mention of autovacuum, there's no mention of analyze.
Sense this is a guide for people going FROM postgresql to db2, it's
forgiveable I guess to leave out autovacuum, but analyze is really
closer to the RUNSTATS command than is the vacuum command. vacuum
analyze would probably be the best match.
The one thing that bothered me is that they didn't mention the
serializable transaction mode in postgresql. It's quite possible that
people migrating from transaction systems utilizing serializable will
run into more bumps in the road on db2 than folks migrating from a
system that uses Read Committed.