oracle sql tuning tips

Tags: service simulation datapump tuning Management production practical fail controlOne: Download routeSecond: The book DrawingThree: the book catalogue The 1th chapter of database operation and maintenance1th. Database Installation Configuration1.1 Preparation for pre-installation 11.2 Installing database Software 51.2.1 Method 1:oui Installation 61.2.2 Method 2: Silent installation 81.2.3 Method 3: Clone installation 111.2.4 Diagnostic Case: Un

/how-to-drastically-improve-your-app-with-an-afternoon-and-instruments) There are some code that can be used to parse the ISO-8601 date string, and simply rewrite it to use it.Well, just use C to make it look good, but do you believe that we have a better plan!If you can control the date format you are working with, try to choose a Unix timestamp. You can easily convert from timestamp to NSDate: -(nsdate*return[NSDate datewithtimeintervalsince1970:timestamp];}This will be faster than using C

Tags: managing tuning direction Cache ACK Analysis binding shared pool SQLAnalysis of effective cursor management"Thinking Analysis"The ability to interpret cursors as shared run schedules when SQL is not shared. There are two directions to the conventional approach:1. Adjust the size of the shared pool (shared operation plan in the library buffer of the shared pool);2,

1 exp Tuning 1.1 Use direct and recordlength options The direct parameter defines whether to use direct path (direct = y) or conventional path (direct = n) for export ). Conventional path export uses the SQL SELECT statement to extract data from the table. direct path export reads data directly from the disk to the PGA and writes the data to the export file as is, this avoids the data conversion process

An analysis of tuning "session management Overhead"IntroductionDuring tuning, the management of sessions is a common problem because the overhead of maintaining sessions is relatively high."The process behaves as follows"Client request (SID) → Listener received → listener derived new process (systemprocess ID) → Client processComments:Spid:system process ID, which represents the process ID of the serverproc

operation time is not long, but there is still a difference in the amount of submissions. Create or replace procedure Proc4asbeginfor i in 1..100000 loopINSERT into t values (i);end Loop;commit;End 5, insert into the collection operation, the whole batch is written to data buffer, and then flushed to the hard disk.Insert INTO T select RowNum from dual connect by level7, according to the hardware environment, open a certain parallel. Cons: Consumes a lot of CPU resources. CREATE TABLE T nologgin

-------------------------------------------------------------------------------------------------| Id | Operation | Name | Rows | Bytes | Cost (%CPU) | Time |-------------------------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 1 | 11 | 189 (1) | 00:00:03 || 1 | RESULT CACHE | 27yjysxpdun18b2utun82bynny | | | | || 2 | SORT AGGREGATE | | 1 | 11 | | ||* 3 | INDEX RANGE scan| idx$$_003600

to select the crosstab (intersection table) as the underlying table, which is the table referenced by the other table.Like what: The EMP table description describes the intersection of the location table and the category table. SELECT * FROM location L, CATEGORY C, EMP E WHERE e.emp_no between, and e.cat_no = C.cat _no and e.locn = L.LOCNwill be more efficient than the following SQL: SELECT * from EMP E, location L, CATEGORY

Transferred from: http://www.cnblogs.com/MR_ke/archive/2010/08/25/1807856.htmlSQL 2005 Performance TuningSQL Server runs for a period of time, and as data accumulates, SQL runs less efficiently, and in order to use business system normal actions, IT departments often need to spend a high price on SQL tuning experts to solve. In fact,

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

Note: This article source: Small yan Kevin "Oracle Database Memory adjustment increased memory "Simulated operating system memory increased from 2G to 8G, adjust the database memory parameters, the example parameter is not as the actual production environment reference, because the need to take, adjust the parameters need to adjust according to the database, to avoid the calf pull cart, Daniel pull the car phenomenon.View RAW configuration Data1[Email

SQL Server Performance Tuning entry (graphic version) Step 1: capture sample data during business peaks(About 2 hours ). The tool used is the profiler that comes with sqlserver, also known as the event probe. For example, after entering, click the button on the leftmost side to create a new trail: DBO permission is required for logon, therefore, you can log on with SA or use Windows integrated verification

first wait event is read by other session. Top 5 Timed Foreground Events Read by other session is defined as follows: Read by other session Definition: When information is requested from the database, Oracle will first read the data from disk into the database buffer cache. if two or more sessions request the same information, the first session will read the data into the buffer cache while other sessions wait. in previous versions this wait was clas

database administrators to test to confirm the obvious functionality, but a second person should be scheduled to test. If you don't have a budget to ask a full-time or part-time tester, consider having the development team check in with each other. If you have a budget for testers, then let your team add load to the application. Streamline the load test process When an application is published as a product, identify some of the factors that work with system performance, and then use it on eve

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

51CTO Learning notes--Linux operation troubleshooting ideas and system tuning tips video Lessons650) this.width=650; "src=" Https://s1.51cto.com/images/201611/25208e84076a9820fec7594656b44c32427a85.png "alt=" 25208E84076A9820FEC7594656B44C32427A85.P "/>First lesson Linux operation and maintenance experience sharing and thinking1, the general host name, write to the hosts under the 127.0.0.1 hostname, becaus

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)

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

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