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Exadata Smart Scan predicate offloading and sequence.NEXTVAL

Thanks to Tanel Poder for this story

There was a question in the twitter-sphere about whether using sequences (sequence.NEXTVAL) in your select query’s projection list would somehow disable smart scans happening?

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The answer is no, sequence use with smart scans works just fine. The smart scan offloading applies to data retrieval row sources (and filtering) only and nothing else. So, what you have in the query’s projection list (the sequence use for example), does not directly affect the smart scan decision. Just like any other operations like sorting, grouping etc, do not have anything to do with smart scans and don’t disable their use. Smart scans are only related to data retrieval and any other operations do not affect them.

Read the entire article at its source

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