XmlElement/XmlAgg/XmlForest Query Takes Longer in 10.2.0 Than In 9.2.0

(Doc ID 1111453.1)

Last updated on MAY 27, 2010

Applies to:

Oracle Server - Standard Edition - Version: 10.2.0.4 and later   [Release: 10.2 and later ]
Information in this document applies to any platform.

Symptoms

A query such as this:

     SELECT       XmlElement
                    ("root",
                     XmlAgg
                       (XmlElement
                          ("row",
                           XmlForest
                           (trunc(ROWNUM/100) a,
                            trunc(ROWNUM/100) b,
                            trunc(ROWNUM/100) c,
                            trunc(ROWNUM/100) c,
                            trunc(ROWNUM/100) e,
                            trunc(ROWNUM/100) f,
                            trunc(ROWNUM/100) g,
                            1 h
                           )
                          )
                       )
                    )
       FROM       dual z
       CONNECT BY LEVEL<=16500
       GROUP BY   trunc(ROWNUM/1650);

runs much slower in 10.2.0.4.0 (for example, Elapsed: 00:01:23.57) than it did in 9.2.0.7.0 (for example, Elapsed: 00:00:13.17).

Cause

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