Обсуждение: Estimation of SQL statements

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Estimation of SQL statements

От
"Kevin Quinlan"
Дата:
Are there any good techniques that estimate the time it will take to execute
an SQL statement, specifically an INSERT, SELECT, UPDATE, or DELETE?  What
factors are important to consider when estimating the execution time of
these types of SQL statements?
Thank you,
Kevin




Re: Estimation of SQL statements

От
Richard Huxton
Дата:
Kevin Quinlan wrote:
> 
> Are there any good techniques that estimate the time it will take to execute
> an SQL statement, specifically an INSERT, SELECT, UPDATE, or DELETE?  What
> factors are important to consider when estimating the execution time of
> these types of SQL statements?
> Thank you,
> Kevin

Complexity and size of statement, complexity and size of tables
involved, complexity and size of indices involved, amount of data (if
any) returned, RDBM design and implementation consideration, OS,
hardware, hardware loading, client design...

Really, you need to know what you are trying to acheive. The best way to
measure speed is to build a system and populate it with dummy data.
Then, analyse your results.

- Richard Huxton