oracle query optimization tool

The products developed by the company basically use Oracle databases. In addition, the data stored and used in the business system is large, and many users use the business system. When the system is busy, about one thousand user colleagues visit the database system. Therefore, users often complain that the system is slow. After clicking the query, the system crashes, the idle value of the minicomputer runn

| 0.00003450 | Reset Query Cache |+----------+------------+--------------------------------------------------------------------+Rows in Set (0.00 sec)To view the details of a single SQL statementMysql> Show profile for query 15;+--------------------+----------+| Status | Duration |+--------------------+----------+| Starting | 0.000049 || Opening Tables | 0.000029 || System Lock | 0.000006 || init | 0.00000

Mysql optimization tool description, mysqlexplain I. Syntax {EXPLAIN | DESCRIBE | DESC} tbl_name [col_name | wild] {EXPLAIN | DESCRIBE | DESC} [explain_type] SELECT select_options explain_type: {EXTENDED | PARTITIONS} 2. Database preparation Table 1: DROP TABLE IF EXISTS `products`;SET @saved_cs_client = @@character_set_client;SET character_set_client = utf8;CREATE TABLE `products` ( `products_id` int(1

[MySQL Notes] SQL optimization tool-explain the output format of the explain command If you have experience using MySQL, you may encounter slow SQL queries in your project. In some scenarios, you can easily locate the problem (for example, when a single table operation has slow SQL queries, check the SQL statement carefully and it is usually easy to locate the index problem). In some complex business scenar

Directory I. Optimization Overview Ii. query and index optimization Analysis 1. performance bottleneck locating Show command Slow query log Explain analysis Query Profiling Analysis Query 2 Index and

a few tables are modified successfully, or are unsuccessful. Begin Tran can play this role by putting a number of SQL statements together and finally a commit. The advantage is that the data is consistent, but nothing is perfect. The cost of the Begin Tran is that all the resources locked by the SQL statements cannot be released until the commit is committed before committing.It can be seen that if the BEGIN TRAN too many SQL statements, the performance of the database is poor. Before this larg

SQL statements cannot be released until the commit is committed before committing.It can be seen that if the BEGIN TRAN too many SQL statements, the performance of the database is poor. Before this large transaction commits, it is bound to block other statements, resulting in many blocks.The principle of the BEGIN Tran is that the less SQL statements that begin TRAN nested, the better it is to ensure data consistency! In some cases, triggers can be used to synchronize data, not necessarily with

Related link parsing Oracle data scanning Oracle SQL optimization guide local scanning method (1) http://www.bkjia.com/database/201205/130424.html Parsing Oracle data scanning Oracle SQL optimization guide local scanning method (2

MySQL Query statement optimizationIndex optimization, query optimization, query caching, Server Setup optimization, operating system and hardware optimization, application-level

is as follows: A.1 Add a write process and adjust the db_block_lru_latches parameter. Example: modify or add the following two parameters Db_writer_processes = 4 Db_block_lru_latches = 8 A and 2 enable asynchronous I/O. IBM is much simpler in this aspect, while hp is a little more troublesome. You can contact Hp engineers. B. db file sequential read refers to sequential read, that is, full table scan. This is also the part we should minimize. The solution is to use indexes and SQL

optimization project in the previous section, which requires that the company optimize the indexes of more than existing tables to improve the existing ones and eliminate invalid indexes. In view of the serious shortage of manpower (the resources of two and a half persons were counted at that time), the idea of Manually changing databases one by one was dispelled. The current program structure does not allow revolutionary practices, but can only be i

Tags: Oracle performance tuning Oracle database optimization Oracle Optimization training Oracle Performance Tuning Oracle Database Performance TuningOracle Performance

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1. IntroductionIn the early stage of application system development, because the database data is relatively small, for querying SQL statements, the use of indexes and the writing of complex views can not understand the performance of the SQL statement of various ways, but the application system in practice, with the data in the database increases, The response speed of the system is one of the most important problems that the system needs to solve at present. An important aspect of system

optimization of algebraic optimization and access path, the statement is processed by the precompiled module and the query plan is generated. It is then submitted to the system for execution at the right time, and the execution results are returned to the user at the end. In the high version of the actual database products, such as

statements are returned for the entire statement, the biggest factor affecting the database response time is physical I/O operations. One of the most effective ways to restrict physical I/O operations is to use TOP keywords. The TOP keyword is a system-optimized term in SQL SERVER used to extract the first few or the first few percentage data entries. Through the application of the author in practice, it is found that TOP is indeed very useful and efficient. However, this word does not exist in

sorted, you can create a compound index on these columns ). ● Use system tools. For example, the Informix database has a tbcheck tool that can be checked on suspicious indexes. On some database servers, the index may be invalid or the reading efficiency may be reduced due to frequent operations. If an index-based Query slows down, you can use the tbcheck tool to

. Minimize cross fragment query, balance balance number is less. 10. Query only the fields you want to use without querying all the fields. 11. When updating the value of a field, using $inc is more efficient than update. 12.apped collections is more efficient in reading and writing than ordinary collections. 13.server-side processing a stored procedure similar to a SQL

.2.1 Querying the character set of the Oracle server sideThere are many ways to identify the Oracle server-side character set, and the more intuitive query method is the following:Sql> Select Userenv (' language ') from dual;USERENV (' LANGUAGE ')----------------------------------------------------Simplified Chinese_china. Zhs16gbkSql>select userenv (' language '

database application development tools and supports Java™SQL pl and PL/SQL routines, XML editor, and other development methods. It can also be integrated with IBM's query optimization tools to Optimize Query performance. Monitoring and Management of database health and availability plan jobs. Data Studio 3.1.1 provides a Web-based monitoring