Category Archives: Oracle Performance

APPROX_COUNT_DISTINCT in Oracle 12c.

Most of time during performance analysis to understand Stale stats, we usually need to check estimated NDV (Number of Distinct values). If data-set is huge , it take considerable time to project desired output using traditional COUNT(DISTINCT) appraoch. For any … Continue reading

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Posted in Oracle 12c New Features, Oracle Internal, Oracle Performance | Tagged , , , | Leave a comment

MIN , MAX and INDEX Access in Oracle.

All Entries in Index are stored as sorted either in ascending or descending order. If we need MIN or MAX for any column being indexed, its should be easier for oracle to fetch same as both would be at index … Continue reading

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Posted in Oracle Internal, Oracle Performance | Tagged , , , , | Leave a comment