oracle sql tuning advisor

As mentioned in parts 1th and 2nd, there are several relatively easy steps to improve performance you can take, one of these steps involves using an automated tool to "guide" you to write SQL statements, there are many production performance analysis or performance tuning tool manufacturers, in the following article, We will examine one of them. Quest Software Many DBAs and developers use a tool called To

One of the practical skills that can greatly improve the performance of SQL TUNING optimization. When we perform SQL optimization, we often encounter the need to sort a large number of datasets and then retrieve the first part of the results from the sorted set. In this case, when we write SQL statements according to t

"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)

fromV$thread T, V$parameter vWHEREV.name= 'Thread' and(V.value= 0 ORt.thread#=To_number (v.value))) I, (SELECTVALUE fromV$parameterWHERENAME= 'user_dump_dest') D;3.2 Using the Tkprof command to beautify the generated trace fileHere is what I often use, for more detailed instructions on the tkprof command, you can see the tkprof command directly enter.Tkprof xxx.trc xxx.txt Explain=system/Oracle sys=nReference URL: http://www.eygle

large print segments18.count (*) is slightly faster than count (1), of course, if you can retrieve by index, the count of indexed columns is still the fastest. 19. Replace the HAVING clause with a WHERE clause to avoid having a HAVING clause, having The result set is filtered only after all records have been retrieved19. Avoid using like ' * ' to avoid using is null or20.Note:A, programmers pay attention to the amount of data in each table.B, the coding process and the unit test process as far

Tags: des style blog http color using strong AR dataBackgroundMySQL and Oracle were used before, and there was not much use for SQL Server. Recently, due to project reasons, to read the database of other projects, take out a gate of the switch history, and the other side of the use of SQL Server, so the study of SQL Se

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

of data ... God horse is not as good as Oracle ...!!!There are some children's shoes simply think that SQL Server is pediatrics, there is no technical content ... It's very simple.On these points, I don't want to spit out anything, I just want to let those friends who really know SQL Server to prove something to SQL S

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