Database Administrator

Show tables or show tables from database_name;Explanation: displays the names of all tables in the current database. Show databases;Explanation: displays the names of all databases in mysql. Show processlist;Explanation: displays all processes

Set two-way MySQL Data Synchronization I. Prepare serversBecause the binlog formats of different MySQL versions (Binary logs) may be different, the best combination is that the MySQL version of the Master is the same or lower than the Slave version,

Delete database link: drop database link linkname;Create database link:Create database link linknameConnect to usernameIdentified by passwordUsing 'Connection string ';If you want to create a global link, you need to use the Keyword: publicCreate

MySQL cluster based on two servers. MySQL can continue to run when any server encounters a problem or goes down.Note: In theory, you can create a MySQL cluster based on only two servers. However, in this architecture, once a server goes down, the

Installation Log [20100707]1. DELL Server2. Install CentOS 5.5 (64-bit)Note that swap is usually 4 GB3. Install Oracle 10.2 (64-bit) Grep MemTotal/proc/meminfo Grep SwapTotal/proc/meminfo Uname-mi4. Check the environment:Rpm-q -- qf' % {NAME}-%

MongoDB is a scalable and high-performance next-generation database. Data in MongoDB is stored as documents, so that complex relationships can be expressed in a single data object. A document may consist of the following parts: an independent basic

1. Stop database-related processesStop the database on two machines respectivelySqlplus "/as sysdba ";SQL> shutdown immediateLsnrctl stop Read: EXP-00056 error reported when exporting data after Oracle10201 RAC upgrade to 10204 You can also use the

1. Preparations for configuration in Linux Environment: Linux: RedHat Enterprise 5.4, DB: Oracle 11g R2 X64, Oracle installed in the/home/oralce_11 directory. The configuration process is as follows: (most of the content is online, and individuals

--. SQL script-- The only note is that f: \ dropobj. SQL is the operated. SQL;-- Your computer does not have a drive F. Replace it with drive D or E.-- Used to delete all objects of the current user-- Use for drop all objects in current user;Set

The Oracle 11g database is installed on RHEL6, and several problems occur on the way. The record is as follows: 1. the kernel settings provided in many documents are based on their memory. You should first know the role of these kernel settings

In PHP project development, it is often used to automatically determine the expiration time of some records. There is an automatic update time timestamp Field in the existing database. The value of another field is updated for more than 7 days based

Use cold backup in a real environment  In the previous article (cold backup for MySQL backup and recovery), we mentioned cold backup. However, there is a problem. The data files we store are stored on the current local disk. If this disk fails, the

Many people think that it is not practical to view the terminal IP address connected to the Oracle server. If it is only a data server, it is useless. If there is a central server and a distributed server, it will reflect its role. Specific

In the performance optimization analysis of Java, JProfiler can be used to analyze information such as CPU consumption, Memory usage, and Thread usage during JVM running. The stored procedures and functions of Oracle called in Java code can also

A set of Oracle 11 GB is implemented in the Linux6.2 system, which may be because the operating system is not properly installed. For example, if each disk of a magnetic array cannot exceed 2 TB, the rpm requires x86_64, there are a lot of

How can I forget the root password of MySQL in Linux? Verification Environment:[Root @ localhost ~] # Rpm-qa | grep mysqlMysql-5.1.71-1.el6.i686Mysql-server-5.1.71-1.el6.i686Mysql-libs-5.1.71-1.el6.i686 [Root @ localhost ~] # Lsb_release-LSB Version:

Execute the following configuration process on all nodes in the cluster! Oracle 9.0.1 and 9.2.0.1 use a user space named watchdogd to monitor the background program to monitor the cluster status and restart the RAC node when a fault occurs. Starting

Linux: 1. Memory: physical memory must be higher than 1 GB Check memory size: grep MemTotal/proc/meminfo 2. swap space: generally twice the memory size. For example, you can set the swap partition size to 3 GB for 1 GB memory. 1) Check the swap

A few days ago, the system was migrated from Oracle to mysql. Many statements are relatively simple, that is, some function modifications, such as to-date. But there are also a few tricky ones, which are recorded here 1. row_number () over

MongoDB environments mainly include StandAlone, Replication, and Sharding. StandAlone: StandAlone environment, usually used for development and testing. Replication: master-slave structure. One Primary and multiple Secondary may have Arbitry.