Database Administrator

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

This note is taken in the previous article . During the learning process, we tested the downloaded DB2 database on the official website (free version). Since DB2 is used in projects, it is also a paid database, so I only use it in project

MySQL implements master-slave Replication 1. To make it easier for mysql to expand automatically as data grows beyond our expectation, and to implement mysql in LVM 1.1 create LVM Create two new partitions, each of which is 5 Gb. My partitions

Source code download wget http://admin.ooopic.com/soft/linux/cmake-2.8.3.tar.gz  wget http://www.wapm.cn/uploads/csft/4.0/coreseek-4.0.1-beta.tar.gz  wget http://ftp.jaist.ac.jp/pub/mysql/Downloads/MySQL-5.5/mysql-5.5.9.tar.gz  Tip: the

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

Flashback is a technology applied from Oracle10g. It can be used to view the data of a database at a time point in the past, restore the database to a State at a time point in time, and restore tables that have been accidentally deleted. Use it to

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

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

1. The data type in Oracle is number (), and the large data type is clob. 2. Create a primary key auto-Increment Introduction to ORACLE SEQUENCE In Oracle, sequence is the so-called serial number, which is automatically increased every time it is

Backup Control File Alter database backup controlfileto '/bk/ctl. bk ';  SQL>Alter system switch logfile; Alter system switch logfile * ERROR at line 1: ORA-03113: end-of-file on communication channel  SQL> conn/as sysdba Connected to an idle

A service has been installed.MysqlInstance.Mysqld_multiCommand to add an instance 1. Assume that there is an existingMysqlInstance, itsBasedirIs/Usr/local/mysql,The data directory is/Usr/local/mysql/data,The configuration file is/Etc/my. cnf # Mkdir/

As soon as I opened the database and did nothing, I found that the hard drive lights went viral. Why? It is preliminarily determined that Oracle's scheduled task is running, but it is unknown which one is running. Therefore, the first step is to

For the strange data, the value of select is obviously 0.0140625, but it is not rounded down by round (vv, 6. It should be calculated as follows: 0.014063, but the actual result is: 0.014062. It violates the rounding principle. Case: Drop table

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

It is easier to add a disk image to ASM using DBCA on node 1. Two new directories are created: ARCHLOG and BACKUP. Node 2 cannot be loaded! [Oracle @ node2bdump] $ export ORACLE_SID = + ASM2 [Oracle @ node2bdump] $ asmcmd ASMCMD> ll Commands: -------

1. view the size of all tablespaces SQL> select tablespace_name, sum (bytes)/1024/1024 from dba_data_files2 group by tablespace_name; 2. view the idle tablespace sizeSQL> select tablespace_name, sum (bytes)/1024/1024 from dba_free_space2 group by