Re: How number of columns affects performance

Francisco,

> I think I understand your point, however it would be very laborious after
> you do all development to find out you need to de-normalize.

Not terribly. Views and Rules are good for this.

> On your experience at which point it would actually help to do this
> de-normalization in PostgreSQL? I know there are numerous factors ,but any
> feedback based on previous experiences would help.

My experience? If you're running on good hardware, it's completely
unnecessary to vertically partition the table. The only thing I'd do would
be to look for columns which are frequently NULL and can be grouped together,
and spin those off into a sub-table. That is, if you have 4 columns which
are generally either all null or all filled, and are all null for 70% of
records then those 4 could make a nice child table.

--
-Josh Berkus

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