Hierarchical Query too slow

Hallo!

My Data is based on a xml-file. The probleme is: find all elements lying under a given element; I do this with the CONNECT BY statement, but this is very slowly if many (about 2.000) elements are under the given element. In this case, the query is much faster, if I check every element(about 40.000) of the tree, if it is under the given element. But this tuning is not nice because I do not know, how many element the query will find. Does anyone know a way to tune the CONNECT BY statement.

Thank you for your help.

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Ralf Hofmann
hofmannb_at_informatik.uni-muenchen.de