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Summary of Oracle Performance Tuning recommendationsPrinciple One: Note the connection order in the WHERE clause:Oracle uses a bottom-up sequential parsing where clause, according to which the connection between tables must be written before other

MS SQL Server Query optimization methodThere are many reasons for the slow speed of queries, which are common1, no indexes, or no indexes (this is the most common problem with query slowness, is the flaw in programming)2, I/o throughput is small,

Analyze and compare execution time plan reads1. View execution time and CPUSET STATISTICS Time Onselect * from Bus_devhistorydataset statistics time offYou can see it in the message after execution.2. View the operation of the query for I/OSET

Analyze and compare execution time plan reads1. View execution time and CPUSET STATISTICS Time Onselect * from Bus_devhistorydataset statistics time offYou can see it in the message after execution.2. View the operation of the query for I/OSET

First, the Database design optimization1. Do not use cursors.Using cursors not only takes up memory, but also locks tables in incredible ways, so that all the performance optimizations that DBAs can do are equal to not being done. Each fetch in the

1. View execution time and CPUSET STATISTICS Time Onselect * from Bus_devhistorydataset statistics time offYou can see it in the message after execution.2. View the operation of the query for I/OSET STATISTICS IO onselect * from

See a very comprehensive SQL optimization article, in the development of the work often do not consider the performance of the lack of (at the beginning of the data volume is not seen the difference in speed). But the more you write, the more you

optimization Problems of databasefirst, the question of the proposedIn the early stage of application system development, due to less development database data, the query SQL statement, complex view of the writing of the performance of the SQL

See a very comprehensive SQL optimization article, in the development of the work often do not consider the performance of the lack of (at the beginning of the data volume is not seen the difference in speed). But the more you write, the more you

Read Catalogue (1) Select the most efficient table name order (valid only in the rule-based optimizer) (2) connection order in the WHERE clause (3) Avoid using ' * ' in the SELECT clause (4) Reduce the number of accesses to the database (