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  2. Query optimization - Wikipedia

    en.wikipedia.org/wiki/Query_optimization

    The query optimizer attempts to determine the most efficient way to execute a given query by considering the possible query plans. [1] Generally, the query optimizer cannot be accessed directly by users: once queries are submitted to the database server, and parsed by the parser, they are then passed to the query optimizer where optimization ...

  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. 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

  5. Query rewriting - Wikipedia

    en.wikipedia.org/wiki/Query_Rewriting

    Query rewriting is a typically automatic transformation that takes a set of database tables, views, and/or queries, usually indices, often gathered data and query statistics, and other metadata, and yields a set of different queries, which produce the same results but execute with better performance (for example, faster, or with lower memory use). [1]

  6. Patricia Selinger - Wikipedia

    en.wikipedia.org/wiki/Patricia_Selinger

    She played a fundamental role in the development of System R, a pioneering relational database implementation, and wrote the canonical paper on relational query optimization. [2] She is a pioneer in relational database management and inventor of the technique of cost-based query optimization.

  7. System Mechanic features - AOL Help

    help.aol.com/articles/system-mechanic-features

    Startup Optimizer™ - Startup Optimizer uses research-based classifications to automatically detect unneeded startup items, while allowing all the important programs and services to load. Program Accelerator™ -This feature uses patented calibration technology to realign program files for the fastest possible access.

  8. 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.

  9. Full table scan - Wikipedia

    en.wikipedia.org/wiki/Full_table_scan

    No index The optimizer must use a full table scan since no index exists. Small number of rows The cost of full table scan is less than index range scan due to small table. When query processed SELECT COUNT(*), nulls existed in the column The query is counting the number of null columns in a typical index. However, SELECT COUNT(*) can't count ...

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