oracle sql tuning books

does not exist in the table. (2) ' | | ' is a character join function. As with other functions, the index is deactivated. (3) ' + ' is a mathematical function. As with other mathematical functions, the index is deactivated. (4) The same index columns cannot be compared to each other, which will enable full table scanning.(+)A. If the number of records in a table that has more than 30% data is retrieved. Using indexes will have no significant efficiency gains.B. In certain situations, using an i

In Oracle database systems, the parameters that play the role of tuning are called initialization parameters, which are recorded in the Initsid.ora file in Oracle 8i and previous versions, while Oracle 9i/10g/ These parameters are recorded in the Spfilesid.ora binary in 11gBasic parameters: A set of adjustable paramete

Run Select Dbms_sqltune.report_tuning_task (: tuning_task) from dual; Error messages, such as the following:Ora-00600:internal error code, arguments: [Kesqsmakebindvalue:obj], [], [],[], [], [], [], []Ora-06512:at "SYS. Prvt_advisor ", line 1624Ora-06512:at "SYS. Dbms_advisor ", line 186Ora-06512:at "SYS. Dbms_sqltune ", line 1008Ora-06512:at Line 8##################Confirmed by MoS, this is a bug. Need to upgrade to 10.2.0.5PSU or 11.2Article:Tuning Advisor terminates with Ora-600[kesqsmakebind

Original: SQL Server Tuning Series Basics (Index operations Summary)ObjectivePrevious articles we introduced how to view the query plan, the introduction of common operators, the way of parallel operations, interested can click to view.This article will analyze in SQL Server, how to use the first indexed items for query performance optimization, by understanding

Books Online logical operators and physical operator references Refer to the book SQL. server.2005. Technical Insider "series Conclusion This article mainly introduces some of the methods of index operation, mainly describes the way we usually apply when writing statements, and to cite a few examples, as a point, in fact, we usually write in the statement is nothing more than this article introdu

execution, although both columns have nonclustered indexes, the theory can be used, but we just choose an optimal index to find, and another directly using bookmarks to find out. Save the previous introduction of the various Gods horse sort to go heavy .... Flow polymerization de-weight .... And so the inhuman operation.It seems that the and connector is a very handsome operator ... So a lot of times when we try to write or, it's better to switch to and more efficiently.Reference documents

Have always wanted to summarize the knowledge of Oracle memory tuning, recently optimized a database memory parameters, look for some information and Google a lot. Now write it down and do the backup. First, overview: Oracle memory can be divided into the system global zone and the process global area in terms of shared and private, that is, the SGA and the PGA

Original: SQL Server Tuning Series Basics (Summary of common operators)ObjectiveIn the previous article we looked at how to view the query plan, this article will introduce the analysis techniques in the query plan we looked at, as well as several of our commonly used operator optimization techniques, the same emphasis on the master of basic knowledge.In this article, we can understand how we normally write

Label:Original: SQL Server Tuning Series Basics (Summary of common operators)ObjectiveIn the previous article we looked at how to view the query plan, this article will introduce the analysis techniques in the query plan we looked at, as well as several of our commonly used operator optimization techniques, the same emphasis on the master of basic knowledge.In this article, we can understand how we normally

Buy Oracle Database Course package and enjoy 85 discount!!Package Address: http://edu.51cto.com/pack/view/id-807.htmlPerformance optimization for Oracle 11g R2 databaseDatabase performance problem is the most discussed topic in database field, because it involves database principle, IO storage, server performance, foreground application and so on, so the performance problem is very test the optimization of

"Performance Tuning" Oracle AWR reporting metrics full resolution What is AWR? ===================================================================================================== AWR (Automatic workload Repository) A bunch of historical energy data, placed on the Sysaux table space, AWR and Sysaux are all 10g, are the key features of Oracle

be sorted, or it can be added to a column (like joins or additions). Any non-indexed item in the ORDER BY statement, or a computed expression, will slow down the query. Double-check the order BY statement to find non-indexed items or expressions that degrade performance. The solution to this problem is to rewrite the order BY statement to use the index, or you can establish another index for the column you are using, and you should absolutely avoid using an expression in the ORDER BY clause.(a)

GROUP BY:Increase the efficiency of the group BY statement by filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.Copy CodeThe code is as follows:Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB having and AVG (SAL) >xxx7, usually, if the statement can avoid the use o

are very readable6. Use where to replace having (if possible)Optimize GROUP BY:Increase the efficiency of the group BY statement by filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster. Copy the code code as follows: Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB hav

In order to be successful, I'll involve some preliminary steps that will be needed to see what happens, including running Plustrce SQL scripts, creating a Explain_plan table, granting roles, configuring Sql*plus environments to view execution plans. All of these steps include "use automatic tracking in Sql*plus" In Oracle