db2 sql performance tuning

Hardware preparation environment: Hard drive: 16 SAS 15 k raid 5 with 512 MCache CPU: AMD 4-core two Memory: 16 GB Software environment: Operating System: RedHat AS4.6 2.6.9-67. ELsmp Mysql: 5.0. Performance Tuning based on different scenarios is as follows: Scenario: Write operations (insert, query, and delete) are intensive, and the data capacity far exceeds the memory size (minimum is more than GB, or ev

"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 tuning; About

oracle| Data | database | Performance Oracle is a high-performance database software. The user can adjust the parameters to achieve the optimization of performance. Performance optimization is mainly divided into two parts: first, the database administrator through the adjustment of system parameters to achieve the goa

%9A%84%E5%93%8D%E5%BA%94%E9%80%9F%E5%BA%A6% e5%88%a9%e5%99%a8/https://my.oschina.net/moooofly/blog/1570635.NETSTAT Network program Communication IP, port, service process number related information (display IP traffic)Https://linux.cn/article-2434-1.htmlCommon commands areNETSTAT-ANTP: Displays information about all TCP connectionsNETSTAT-TNLP: Lists TCP in the listenerNETSTAT-ANLP: List all the listening6.iftop: Network interface traffic monitoring, can be specific to a specific IP address traf

support Create compressed data page19, can dynamically turn off the InnoDB update metadata statistics function: Pollution buffer pool, annlyze table and Show table status will also read the table metadata pollution buffer pool20. Enhanced copy function21. Relay Log Self-repair22, open InnoDB Strict check mode23, dynamically change the system configuration parameters, new parameters can be changed dynamically is a separate table space, InnoDB lock timeout time24. Changes in

2009 21:00 1 7472 25 October 2009 22:00 1 7473 25 October 2009 23:00 1 7474 26 October 2009 00:00 1 7475 26 October 2009 01:00 1 7476 26 October 2009 02:00 1 7477 26 October 2009 03:00 1 7478 26 October 2009 04:00 1 7479 26 October 2009 05:00 1 7480 26 October 2009 06:00 1 7481 26 October 2009 07:00 1 7482 26 October 2009 08:00 1 7483 26 October 2009 09:00 1 7484 26 October 2009 10:00 1 Specify the Begin and End Snapshot Ids ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Enter value for begin_snap:7451

operations, although PHP file operation efficiency is not low;41, optimize the Select SQL statement, as far as possible, as little as possible to insert, update operation (on the update, I was a bad batch);42, as far as possible the use of PHP internal functions (but I have to find a php non-existent function, wasted can write a custom function of time, experience problem ah!);PS: Built-in functions are nearly an order of magnitude more efficient tha

filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.The 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 of subqueries, as far as possible without sub-query.Because the overhead

. procname from syscat. routines R, syscat. procedures proc, syscat. packagedep pdep where pdep. bname = upper ('% 2') and pdep. bschema = upper ('% 1') and R. specificname = Proc. specificname and pdep. pkgname = 'P' | substr (char (R. lib_id + 10000000), 2 )" Echo --- dependent UDF --- DB2 select routineschema, routinename from syscat. routinedep where bschema = upper ('% 1') and bname = upper (' % 2') and btype = 't'order by bname Echo -

Index | performance ORA FAQ Performance Tuning Series-- The Oracle (tm) Users ' co-operative FAQ Why would a reverse index to useful when the leading column of the "index is" generated from a sequence? When the first column of the index is generated by the sequence, what is the use of a reverse index? --------------------------------------------------------------

threads.Of course, here are a few thread operations can set their own, the maximum recommended for the current system configuration of the logical core number, of course, the large set can be just useless.Second , index Hint hints (index Hint)The so-called index hint hint is to force the query optimizer to perform a scan of a query statement or use a specified index.In this way, we often use in the tuning of a way, many times we create the index is i

This article introduces 10 MySQL Performance tuning methods. each method is very detailed and practical. For more information, see MYSQL, which is the most popular WEB backend database. WEB development languages have developed rapidly recently. PHP, Ruby, Python, and Java have their own characteristics. although NOSQL has been mentioned more recently, I believe most architects will choose MYSQL for data sto

Mysql Tomcat C3p0 System Performance Tuning personal summary, System Information The application logic is to use c3p0 to query data in the database and return Json data over http. 1. the initial test result JMeter test result before optimization No. Type Original 1000 data bigger 1 500 Connection 250 query/S 63q/S70q/S 2 1000 connections 255q/S 57q/S65

Query performance tuning is a big topic, where the technology involved is very broad, but we can generally divide it into the following levels: 1. Reduce data access. The related technique is to create an appropriate index that converts time-consuming operations such as full table scans, index scans (scan), to index lookups (seek). Establish the correct index, can make the database query

you to optimize the SQL statement for join. Also, the fields that are used for join should be of the same type. For example, if you want to join a DECIMAL field with an INT field, MySQL cannot use its index. For those string types, you also need to have the same character set. (The character set of two tables may be different) "Avoid select *" "always set an ID for each table" We should set an ID for each table in the database as its primary key, a

· InnoDB Storage Engine 14. Using an Object-relational mapper (relational Mapper) With ORM (Object relational Mapper), you can gain reliable performance gains. All the things an ORM can do, can be written manually. However, this requires a senior expert. The most important thing about ORM is "Lazy Loading", that is to say, only when the need to take the value of the time to really do. But you also need to be careful about the side-effects of this mec

|| Slow_launch_time | 2 |+------------------+-------+Mysql> show global status like '%slow% ';+---------------------+-------+| variable_name | Value |+---------------------+-------+| Slow_launch_threads | 0 || slow_queries | 4148 |+---------------------+-------+The configuration of the record slow query, the execution time of more than 2 seconds is slow query, the system shows that there are 4,148 slow query, you can analyze the slow query log, find the problem of

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

-------------------------------------------------------------------------| Id | Operation | Name | Cost (%CPU) |-------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 4 (0) || 1 | TABLE ACCESS by GLOBAL INDEX rowid| SALES | 4 (0) || 2 | INDEX RANGE SCAN | Index_qu_sold | 3 (0) |-------------------------------------------------------------------------9 Rows selectedSql> alter session Set "_use_nosegment_indexes" =true;Session altered.Sql> CREATE index

This article describes some of the most useful ways to adjust the JSP and servlet to make your servlet and JSP pages respond faster and more scalable. And in the case of increasing the number of users, the system load will show a trend of smooth and long. In this article, I'll use some examples and configuration methods to make your application's performance unexpectedly elevated. Some of these tuning techn