SQL statement optimization improves database performance and SQL statement database performance
In systems with unsatisfactory performance, apart from the fact that the application load exceeds the server's actual processing capacity, it is more
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,
The optimization of SQL statements is to convert poorly performing SQL statements into the same performance SQL statements with the same purpose.AI automatic SQL optimization uses AI technology to automatically rewrite SQL statements to find the
First, let's look at the sample SQL statement to be parsed:
Copy codeThe Code is as follows: select * from dual
SELECT * frOm dual
Select C1, c2 From tb
Select c1, c2 from tb
Select count (*) from t1
Select c1, c2, c3 from t1 where condi1 = 1
The optimization of SQL statements is to reduce the performance of SQL statementsConversionSQL statements with the same performance as the target. Artificial Intelligence automatic SQL optimization is the use of artificial intelligence technology,
Chapter 4 SQL statement ProcessingBefore adjustment, we need to know some background knowledge. Only by knowing this background knowledge can we better adjust SQL statements.This section describes the basic process of SQL statement processing,
The performance of the system is not ideal, except in part because the application load does exceed the actual processing capacity of the server, more because the system has a large number of SQL statements need to be optimized. In order to achieve
For statements to run, there are other factors to consider, in addition to the execution plan itself, such as the compile time of the statement, the execution time, the number of disk reads, and so on.If the DBA is able to run the problem statement
This document is compiled and summarized based on relevant information. It mainly describes the most authoritative and correct methods and steps for obtaining SQL statement execution plans in Oracle databases.
This document is compiled and
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