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Multi-objective query optimization [10] models the cost of a query plan as a cost vector where each vector component represents cost according to a different cost metric. Classical query optimization can be considered as a special case of multi-objective query optimization where the dimension of the cost space (i.e., the number of cost vector ...
PDFtk (short for PDF Toolkit) is a toolkit for manipulating Portable Document Format (PDF) documents. [ 3 ] [ 4 ] It runs on Linux , Windows and macOS . [ 5 ] It comes in three versions: PDFtk Server ( open-source command-line tool ), PDFtk Free ( freeware ) and PDFtk Pro ( proprietary paid ). [ 2 ]
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
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]
The query evaluation, and thus query containment, is LOGCFL-complete and thus in polynomial time. [9] Acyclicity of conjunctive queries is a structural property of queries that is defined with respect to the query's hypergraph : [ 6 ] a conjunctive query is acyclic if and only if it has hypertree-width 1.
[10] From 2014 through 2016, Dr. Selinger was the Chief Technology Officer at Paradata (Paradata.io) where she worked on challenging problems in data harmonization, curation, provenance, and entity resolution to provide transparency to the supply chain. Paradata technology transforms real-time data into verified insights and executable actions.
In Jet 3.0 onward these are then optimized using the Microsoft Rushmore query optimization technology. The query is then executed and the results passed back to the application or user who requested the data. Jet passes the data retrieved for the query in a dynaset. This is a set of data that is linked dynamically back to the database.
Database tuning describes a group of activities used to optimize and homogenize the performance of a database.It usually overlaps with query tuning, but refers to design of the database files, selection of the database management system (DBMS) application, and configuration of the database's environment (operating system, CPU, etc.).