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Does the Query Optimizer Cost PX Distribution Methods?

The short answer to this question is “yes”, it does. Unfortunately, the distribution costs are not externalized through the execution plans and, as a result, this limitation (yes, it is really a limitation in the current implementation, not a bug) confuses everyone that carefully look at the information provided in an execution plan of a […]

Does CREATE INDEX Gather Global Statistics?

You can add the COMPUTE STATISTICS clause to the CREATE INDEX statement. It instructs the SQL statement to gather and store index statistics in the data dictionary, while creating the index. This is useful because the overhead associated with the gathering of statistics while executing this SQL statement is negligible. In Oracle9i, the gathering of […]

Hints for Direct-path Insert Statements

Up to Oracle Database 10g Release 2, direct-path inserts are supported only by INSERT INTO … SELECT … statements (including multitable inserts), MERGE statements (for the part inserting data), and applications using the OCI direct-path interface (for example, the SQL*Loader utility). At the statement level two methods are available to specify that a direct-path insert […]