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Message Posted: Thu, 13 Mar 2003 @ 10:54:19 GMT


     
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Subj:   Fast Path Insert
 
From:   Kumaran Anantaraman

(SQL Reference - Volume 6 Data Manipulation Statements-V2R4.1) The manual describes the FAST PATH INSERT as an optimization when ... target table is empty. But it did not require that the PIs match between the source and target table. It then says " Columns defined with the COMPRESS option cannot participate in fast path optimizations, so if you perform an INSERT SELECT operation on compressed columns, fast path optimization is not specified by the Optimizer when it creates an access plan."

Q1 : Is the mysterious 'specified by the Optimizer', the fact that TJ is not used? (one write) or is there more to it?? Q2 : Why did COMPRESS negate this optimization?? If source and target differ in the COMPRESS, then a spool is used - which is fine, but TJ is still not needed???



     
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