Index Tuning

Oracle indexes can be tuned looking to three main characteristics: SELECTIVITY: you can calculate index selectivity using this formula: SELECT DISTINCT_KEYS/NUM_ROWS SELECTIVITY FROM DBA_INDEXES / Values range from 0 to 1, where 1 is the optimal value (UNIQUE indexes and PK), while with values near to 0 performance is lower CLUSTERING FACTOR: measures how many…
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11 Dicembre 2013 0