ArcerZhang`s Technology Blog

摘要： Auto Sort Area ManagementkParameter for automatic sort area management:-PGA_AGGREGATE_TARGET(Ranges from 10MB to 4000GB)-WORKAREA_SIZE_POLICY （AUTO | MANUAL）(Oracle 推荐使用自动化管理)Replaces all *_AREA_SIZE parametersSQL> show parameter PGA_AGGREGATENAME TYPE VALUE---... 阅读全文

摘要： ObjectivesAfter completing this lesson,you should be to do the following:List the operations that use temporary space.Create and monitor temporary tablespaces.Identify actions that use the temporary tablespaceDescribe and different disk sorts and memory sortsIdentify the SQL operations that require 阅读全文

摘要： Session 信息的保存，有两种途径:1、基于Cookie的2、基于URL的Session的使用步骤1、session_start(); 开启一个会话，返回任何与session相关的信息.2、session.auto_start=0|1在php.ini文件中修改参数session.auto_start=1,那么在每个页面之前就可以不用通过session_start()函数来启动session.不过因为类的加载都是要在启动session之前加载如此这样就无法将对象设置到session中，因此一般不会将php.ini文件中的参数session.auto_start设置为1. 阅读全文

摘要： #!/bin/shPATH=$PATH:$HOME/binexport PATHORACLE_BASE=/RealDataORACLE_HOME=$ORACLE_BASE/oracleORACLE_SID=DATACENTERPATH=$ORACLE_HOME/bin:$PATHLD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATHexport ORACLE_BASE ORACLE_HOME ORACLE_SID PATH LD_LIBRARY_PATH DISPLAY#add enviroment variable nls_langexport N 阅读全文

摘要： Generate the Execution PlanCan be used without tracingNeeds the plan_table table utlxplan.sqlCreate the explain plan:SQL> explain plan for 2 select * from my_all_objects;Explained.Query plan_table TableQuery plan_table to display the execution plans:Query plan_table directly.Use script utlxpls.sq 阅读全文

摘要： Hint帮助Optimizer得到最优的查询结果.Using Hints in SQLSELECT * FORM employees;SELECT /*+ First_rows */ FROM employees;Optimizer Plan StabilityUsers can stabilize execution plans,to force applications to use a desired SQL access path.A consistent execution path is thereby maintained through database changes.Thi 阅读全文

摘要： Understanding OptimizerThe query optimizer performs the following steps:The optimizer generates a set fo potential plans for the SQL statement based on available access paths and hints.The optimizer estimates the cost of each plan based o statistics in the daa dictionary for the data distribution an 阅读全文

摘要： ObjectivesAfter completing this lesson,you should be able to do the following:Control optimizer optionsUse optimizer hintsEmploye plan stabilityUse store outlines(在10g,11g已经过时)Use SQL Trace and TKPROFOverviewThe purpose of this lesson is:To provide mthods to determine the resources used by SQL state 阅读全文

摘要： 1、查看oracle server NLS_LANG参数信息；以SYSDBA身份登录view nls_parametersSQL> select * from v$nls_parameters where parameter='NLS_CHARACTERSET';PARAMETER VALUE------------------------------ ------------------------------NLS_CHARACTERSET AL32UTF82、修改环境变量export NLS_LANG# .bash_... 阅读全文

摘要： Query dba_tables for IOTDBA_TABLES->IOTSQL> SELECT table_name,iot_name,iot_type FROM dba_tables WHERE table_name LIKE '%IOT%';TABLE_NAME IOT_NAME IOT_TYPE------------------------------ ------------------------------ ------------SYS_IOT_OVER_12334 ... 阅读全文