Database Administrator

Write down some important knowledge about Oracle databases for future reference! I. file systems and functionsExecution file: the Core of the Oracle system. data files can only be identified by Oracle processing programs. it is meaningless to leave

MySQL Databases can not only be joined between tables, but also can be joined by themselves. This function is quite comfortable. Let's take a look at how to make the table join itself in mysql.Create a table in MySQLCreate table d(Id int (10)

Install the Oracle 10gR2 database on the text interface of Fedora 14 (32-bit i686: 1. Create users and user groups[Root @ xinchang ~] # Groupadd-g 502 dba[Root @ xinchang ~] # Groupadd-g 503 running[Root @ xinchang ~] # Groupadd-g 504 asmadmin[Root @

Multiple Oracle databases physically stored in the network can be logically considered as a single large database. Users can access the data in the remote database through the network, the collaborative processing between servers is completely

Bulk collect can be used to load the query results to collections at a time, instead of processing them one by one Using CURSOR. You can use bulk collect in select into, fetchinto, and returning into statements.Note that when bulk collect is used,

====================================== SRVCTL ================ ======================1. List all configured DatabasesSrvctl config database 2. display all services of the specified cluster DatabaseSrvctl config service-d GDTV 3. view the status of

The strace in Linux can help us track program system calls. LGWR is an important process in Oracle and is responsible for writing redo logs into online redo logs. Let's try to use strace to peat LGWR behavior. First, find the LGWR process Number:

SQL> variable jobno number;SQL> beginSQL> DBMS_JOB.submit (: jobno, 'pro_name (); ', sysdate, 'sysdate + 1 ');Dbms_job.submit (: job1, 'myproc; ', sysdate, 'sysdate + 100'); -- runs the test process once every minute for 1/1440 minutes.SQL>

The Linux server uses the system crontab to regularly execute Backup files and save the backup results by date to achieve the backup purpose. 1. Create the path to save the backup file/mysqldata # Mkdir/mysqldata 2. Create the/usr/sbin/bakmysql

The lpad function is an Oracle database function. the lpad function fills the string with the specified characters on the left. It can be understood from its literal meaning that l is short for left, pad is the meaning of fill, so lpad is the

During Oracle development, various forms of report presentation are often encountered. Some reports cannot be directly written using SQL statements, and must be implemented in concert with SQL, however, the report query speed is slow and is not

Every time the server administrator notifies that a file occupies too much hard disk space, it is estimated that the tablespace of the Oracle database has become larger. There is no way. You need to be aware of the number of tablespaces currently

How to handle HANG Databases 1. Generate systemstate dump:SQL> sqlplus-prelim/as sysdbaSQL> alter session set max_dump_file_size = unlimited;SQL> alter session set events 'immediate trace name systemstate level 10 ';Wait for some 30 secondsSQL>

I. Principle of MySQL master-slave Replication What is mysql master-slave Replication Mysql supports several different forms of replication, such as single bidirectional, chained cascade, and asynchronous replication. During the replication process,

Create error table: Create sequence seq_error_log_id;Create table error_log (id number, unit_name varchar2 (30 ),Err_code varchar2 (100 ),Err_desc varchar2 (4000 ),Err_date date ); Automatically expand the partition package: Create or replace

MySQL installation methods include rpm and source code compilation and installation. This article will demonstrate installation without compilation.I. installation and configuration 1. Create a mysql user and decompress the mysql installation

11.1 view fra location SQL> show parameters db_recovery_file_dest NAME TYPE VALUE ----------------------------------------------------------------------------- Db_recovery_file_dest string Db_recovery_file_dest_size big integer 0 Select * from v $