The underlying platforms do not like this.
This isn't the only issue that can arise, nor are they all at the same limit. The tables these are added to also already have some columns.
Our documentation recommends no more than 100 custom attributes per object.
There are Oracle limits that you can hit too, something (IIRC) like 1000 columns maximum in a VIEW before you hit Oracle errors, and some of the underlying views created by PPM add multiple columns per custom attribute on them (look at the definition of ODF_PROJECT_V for example) - so stuff would start falling over when you might have >300 custom attributes.
You would have to question any design choice that hit these sort of limits anyway (either performance issues like in your linked article) or just "stuff starts falling over" problems with underlying Oracle errors.
100 custom-attributes max its pretty reasonable!
Thanks Dave, I agree with your experience and sentiments, the 1000 column view limit is definitely the most common one that occurs.
Usually compounded or occurring with investments because it isn't realised that 'investment' itself isn't a real object, it's abstract, and so its count of attributes are added to all 'concrete' investment objects like projects, assets, etc.
I will likely have some additional follow-up comments to make soon too.
Wanted to get this one out there though, it was news to me and occasionally we are also hit by "our temp space is blowing up and our DBAs are unhappy" problems also, and this may well be one of the reasons.