Database Administrator

DataGuard how to transmit Redo to Standby DataGuard transfers redo to standby and then applies the redo on standby to ensure data consistency between the two.The lgwr process is used to transmit redo logs. In the lgwr transfer mode, the lgwr process

Oracle Database hang instance analysis Symptom: Neither common users nor sysdba can log on, resulting in service interruption. Analysis process: 1. Do hanganalyze and systemstate dump first $ Sqlplus-prelim "/as sysdba" SQL> oradebug setmypid

MySQL views the number of connections and status information I. Problem Description Today, I was asked by my O & M colleagues that the number of connections to two MYSQL databases has exceeded the monitoring threshold (700). Of course, their

[PL/SQL series] use dynamic SQL for Oracle stored procedures I believe everyone knows about the Oracle stored procedure. The following describes how to use dynamic SQL in the Oracle stored procedure. I hope this will help you. Create or replace

What should I do if I forget the MySQL password root? What if you forget the root password of the online MySQL database one day? You will often think of the skip-grant-tables parameter. The specific steps are as follows: 1. Shut down the MySQL

MySQL cross-platform (Windows, Linux, Mac) use and Installation MySQL is actually a cross-platform lightweight database, which is usually used for development. Writing programs may require cross-platform development. Next I will introduce how to use

Virtual indexes for Oracle Performance Optimization A virtual index is a pseudo index defined in the data dictionary, but there is no relevant index segment. The purpose of a virtual index is to simulate the storage of indexes, instead of creating a

MySQL5.5.32 compilation and Installation MySQL IntroductionMySQL is a relational database management system developed by MySQL AB in Sweden. It is currently a subsidiary of Oracle. MySQL is the most popular Relational Database Management System. In

Introduction to Oracle High Water Mark (HWM) 1. What is high water level? High water level is the boundary between Oracle and unused space. It can also be understood as the boundary between data files and between non-data files, however, the data

CentOS 6.5 installation of Redis and startup script I. Download and install Redis in CentOS 6.5 1. Download the source code, decompress it, and compile the source code. # Wget http://download.redis.io/releases/redis-2.8.3.tar.gz# Tar xzf redis-2.8.3.

Install and configure Redis on a Linux Server 1. Download and install redis On a Linux server, run the following command on the command line (the General source code of cd./usr local/src is put here (the installation of source code is recommended ))

Understanding of B + tree and index in MySQLOverview Nature: Databases maintain certain data structures and reference (point to) data in some way Index selection principle: the structure of the index should minimize the number of disk I/O

Ubuntu 12.04 64-bit compilation and installation of MySQL 5.5.29 Step 1:Go to the official mysql website and go down to compile the source code package.Mysql Website: www.mysql.comDownloads (MySQL Community Server)Download the version, select source

Understanding of MySQL transaction commit and rollback errors I. Cause Begin or start transaction to START a TRANSACTION Rollback transaction rollbackCommit transaction validation The transaction is interpreted as follows: a transaction is composed

Install MySQL in Linux source code Today, in Ubuntu and CentOS, MySQL has been installed many times with the source code. Remember to write it down before you forget it. There is no difference in the installation process in Ubuntu and CentOS. 0.

MyCAT global serial number When database/table sharding is implemented, the auto-increment primary key of the database cannot be globally unique. Therefore, MyCat provides global sequence and multiple implementation methods including local

Snapshot standby features in Oracle 11g Among Oracle 11g, data guard is the most attractive. In addition to the Real-Time query feature of active data guard (you can open the physical standby database in read-only mode while the MRP process can

Application change deployment in production mode of Weblogic Scenario overview The next AdminSever in production mode allows WebLogic to manage multiple managedsevers. When deploying an application for the first time, you can select multiple

MySQL-Performance Optimization-about InnoDB buffer pool flush policies Background We know that InnoDB uses the buffer pool to cache data pages read from the disk to the memory. The buffer pool is usually composed of several memory blocks plus a

Basic concepts of databases: mandatory for interviews, and basic concepts of databases Today, I will share with you the basic concepts related to database collection, which will be very helpful for your future work. 1. superkeys, candidate keys,