Overview of Query Hints

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Let us get an overview of query hints.

  • We can specify hint using /*+ HINT */ as part of the query.

  • Make sure there are no typos in the hint.

  • If there are typos or there no indexes specified as part of hint, they will be ignored.

  • In case of complex queries, CBO might use incorrect index or inappropriate join.

  • As an expert if we are sure that, the query should be using a particular index or right join, then we can force the optimizer to choose such index or join type leveraging hint.