Database Administrator

Redo logs are generally set to convert logs to 10-20 minutes. Too frequent conversion may affect the performance. if the checkpoint incomplete in the AWR report is large, the switching between redo logs is too frequent. you can increase the redo log

Usage conditions:For Linux or Solaris machines, we recommend doule buffer cache in AWR, and db file sequential read is the top wait event. Size:2-10 times the buffer cache. It cannot be less than 2 times. If ASMM is used, 2-10 times the

By default, parallel_max_servers is enabled if it is greater than 0. Alter session enable parallel [ddl | dml | query];Alter session disable parallel [ddl | dml | query];Alter session force parallel ddl parallel 5; Several views used to analyze DB

The Alter database processing process is not as scary as alter table, and the processing logic is clear. Sort the information as follows: 1. Check whether the database name is valid Call check_db_name () (table. cc: 2876) to check whether the

There are more than 40 stored procedures under the dbms_stats package. It is very important to generate the execution plan. Common examples include:Analysis database (including all user objects and System Objects): gather_database_statsAnalyze all

Introduction: Recently, I often see some posts about Oracle GG implementation cases in forums. It is true that GG does not have a lot of comprehensive information in various forums, especially the real implementation cases are even more rare. In

MySQL replication is actually to copy data from one node (master) to another node (slaves). Of course, depending on the application architecture, the method is also different, the replication between MySQL servers uses the binary log mechanism.

First, what will happen if Oracle is not uninstalled and then installed in Linux? In a production environment installation, an error occurs during Oracle installation, which leads to oracle Installation failure, ignore the previous installation and

I have previously written an article about Oracle Apps patch using the hotpatch mode: Oracle EBS patch using the adpatch tool (hotpatch mode) [see ], today, we will record how to use Maintainance Mode to Patch Oracle EBS. 1. Check whether the system

Nesting another SQL statement in an SQL statement is called a subquery. This query statement is used as a condition for another query statement. The SQL statement that contains other SQL statements is called the parent query. Example: If you want to

[Root @ localhost home] # vi test. sh#! /Bin/shOracle_HOME =/oracle/ora10/productExport ORACLE_HOMEUserpwd = test/test@10.11.0.235: 1521/ora10g$ ORACLE_HOME/bin/sqlplus-S $ userpwd Alter session set nls_date_format = 'yyyy-mm-dd hh24: mi: ss

ORA-01779 errors may occur when you try to update a subquery in Oracle. The error message is as follows: ORA-01779: cannot modify a column which maps to a non-key-preserved table for example, this error occurs when you use the following update

Continuous Oracle statistics based on the same data Create table test (Id number (20 ),Val NUMBER (20))Insert into test values (1, 5 );Insert into test values (2, 10 );Insert into test values (3, 10 );Insert into test values (4, 10 );Insert into

I haven't written any logs for a long time! I have summarized some knowledge points in my work recently. Here I will record them: This article is about the automatic analysis of Oracle 11g. In 11g, automatic analysis is significantly different

An article library contains two tables: category and article. There are 10 classified data entries in category. There are 0.2 million articles in articles. There is a "article_category" field in article that corresponds to the "category_id" field in

1. Basic Application of Stored Procedures 1. Create a stored procedure (SQL window) Create or replace procedure update_staffAsBeginUpdate staff set name = 'xy ';Commit;End update_staff; The stored procedure is suitable for updating operations,

-- View the number of sessionsSelect count (*) from v $ session;-- View the number of processesSelect count (*) from v $ process;-- View the number of concurrent connections of the databaseSelect * from v $ session where status = 'active ';-- View

1. Consistentgets description When we use autotrace to view execution plans and statistics, the following information is displayed: 0 recursive cballs: recursive call. General cause: dictionary cache miss; dynamic storage expansion; PL/SQL statement

My system: Red Hat Enterprise Linux Server 6.0.My Oracle: 10g. 2.1 Installation Process in silent mode:1) confirm the disk size: u01 5G; swap 400 m;Du-sh/tmp/Df-h 2) install related dependency packages (query the official installation guide

As shown below, 1. Restore the database test to the data volume first.2. Then shudown test. copy all datafiles, tempfile, and redofile to the yldata volume.3. Use pfile, open test Library, copy pfile --> ylpfile to change the ylpfile of the