Performance Tip: Avoid ORed Folder predicates (2)

July 26, 2007 at 12:03 pm | Posted in Documentum and Oracle, Performance | Leave a comment

I little while ago I posted some advice on avoiding performance problems with queries that look like this:

select ... from ... where folder('/ABC') or folder('/XYZ')

In addition to the advice I gave in that original post you can also write the above as:

select ... from ... where folder('/ABC','/XYZ')

This construct appears to perform well and should definitely be preferred to the version with ORed Folder predicates.

The general syntax for the folder predicate is:

folder(path1[, path2,...][,descend])

so you can use the descend clause. This means that the following:

select ... from ... where folder('/ABC',descend) or folder('/XYZ',descend)

could also be better written as:

select ... from ... where folder('/ABC','/XYZ',descend)

Of course if you need to mix your folder descend predicates then your back to the original solution.

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