COST-BASED ORACLE FUNDAMENTALS

cost-based-oracle-fundamentals

The question, “Why isn’t Oracle using my index?” staleness be digit of the most favourite (or perhaps unpopular) questions ever asked on the Oracle support forums. You’ve picked just the correct columns, you’ve got them in the saint order, you’ve computed statistics, you’ve patterned for invalid columns&emdash;and the optimizer categorically refuses to ingest your finger unless you suggestion it. What could mayhap be feat wrong? If you’ve suffered the interference of watching the optimizer do something completely freakish when the prizewinning enforcement organisation is totally obvious, or spent hours or life disagreeable to attain the optimizer do what you poverty it to do, then this is the aggregation you need. You’ll become to undergo how the optimizer “thinks,” see ground it makes mistakes, and discern the accumulation patterns that attain it go awry. With this aggregation at your fingertips, you module spend an large turn of instance on artful and trouble-shooting your SQL.

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