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  2. Query optimization - Wikipedia

    en.wikipedia.org/wiki/Query_optimization

    Classical query optimization associates each query plan with one scalar cost value. Parametric query optimization [9] assumes that query plan cost depends on parameters whose values are unknown at optimization time. Such parameters can for instance represent the selectivity of query predicates that are not fully specified at optimization time ...

  3. Query plan - Wikipedia

    en.wikipedia.org/wiki/Query_plan

    Some query tools can generate embedded hints in the query, for use by the optimizer. Some databases - like Oracle - provide a plan table for query tuning. This plan table will return the cost and time for executing a query. Oracle offers two optimization approaches: CBO or Cost Based Optimization; RBO or Rule Based Optimization

  4. Filter and refine - Wikipedia

    en.wikipedia.org/wiki/Filter_and_refine

    Initially, a query processor filters data through mechanisms like query optimization, where queries are reformulated and simplified to reduce the computational cost. This process might involve selecting the most efficient query plan or utilizing statistical estimates to quickly prune large data sections that do not match the query criteria.

  5. Relational calculus - Wikipedia

    en.wikipedia.org/wiki/Relational_calculus

    Query optimization consists in determining from a query the most efficient manner (or manners) to execute it. Query optimization can be formalized as translating a relational calculus expression delivering an answer A into efficient relational algebraic expressions delivering the same answer A.

  6. Relational algebra - Wikipedia

    en.wikipedia.org/wiki/Relational_algebra

    Query Optimization This paper is an introduction into the use of the relational algebra in optimizing queries, and includes numerous citations for more in-depth study. Relational Algebra System for Oracle and Microsoft SQL Server; Pireal – An experimental educational tool for working with Relational Algebra

  7. Sargable - Wikipedia

    en.wikipedia.org/wiki/Sargable

    A query failing to be sargable is known as a non-sargable query and typically has a negative effect on query time, so one of the steps in query optimization is to convert them to be sargable. The effect is similar to searching for a specific term in a book that has no index, beginning at page one each time, instead of jumping to a list of ...

  8. AOL Search FAQs - AOL Help

    help.aol.com/articles/aol-search-faqs

    Alternatively, you can view and clear your search history by following the steps listed below. To clear Search History: 1. Go to search.aol.com. 2. Click Sign In. 3. Type your AOL Username or Email and Password in the text boxes and then click Sign In. 4. Type a keyword in the search box and click Search. 5. Click the History drop-down arrow.

  9. Query rewriting - Wikipedia

    en.wikipedia.org/wiki/Query_Rewriting

    Query rewriting may be rule based [2] or optimizer based. Some sources discuss query rewriting as a distinct step prior to optimization, operating at the level of the user accessible algebra API (e.g. SQL). [citation needed] There are other, largely unrelated concepts also named similarly, for example, query rewriting by search engines. [3]