Database Administrator

DB2 memory usage too high Optimization Recently, I was working on the benchmark of DB2 and found that the memory usage of the database was very high. Because the benchmark test was performed, there were not many tables, And I mainly tested one of

DB2 view execution plan In DB2, it is not convenient to view the SQL Execution Plan for other databases. Several steps are required. Here I organize the steps into shell scripts for ease of use, as shown below: #! /Bin/sh Db2 connect to Db2-tvf $

Oracle segmented Query For example, you can use the LAG and LEAD statistical functions to query segments in Oracle on the Internet, the Lag and Lead functions can retrieve the data of the first N rows and the value of the last N rows of the same

Some problems encountered during RedHat + Oracle installation are worth summarizing Yesterday, a RedHat Linux version 5 + Oracle was installed in the middle of the night. Several things were encountered during the installation. The statement is as

Exploration of MySQL MMM data inconsistency The slave points to the key log output of the new master. Through the log output, we can roughly understand the execution process of MMM automatic failover or online switching. -- Automatic failover and

Oracle Partition Table execution plan Oracle Partitioned Tables have many advantages, such as being big, small, and small. With parallel use, loap can often improve the performance by dozens or even hundreds of times. Of course, poor table design

Oracle restrict connected IP addresses In Oracle, you can control which IP addresses can connect to the database and which IP addresses cannot connect to the database. In 9i and later, setting the allowed IP address and the prohibited IP address is

An exception is thrown when MySQL queries the default time. Symptom A MySQL table is created with a field of the Date type. The default value is 0000-00-00 00:00:00. The PrepareStatement is used for query and the query result is ResultSet, the

MySQL MHA introduction and advantages MHA is the best choice for many enterprises that use MySQL databases for high availability. It is easy to use and powerful, and implements automatic master-slave failover Based on the MySQL replication

MySQL Cluster Installation Environment Description System Environment: CentOS 6.5 mini (64bit)Software Version: mysql-cluster-advanced-7.3.7-linux-glibc2.5-x86_64.tar.gz IP Address:MGM: 192.168.100.211 NDBD1: 192.168.100.212 NDBD2:

Oracle user unlock Connect first SQL * Plus: Release 12.1.0.2.0 Production on Thursday February 12 15:40:422015 Copyright (c) 1982,201 4, Oracle. All rights reserved. Enter the User name: system Enter the password: Last Successful Logon Time:

Basic Oracle database operation statements This article mainly introduces the basic statements and concepts of Oracle database management. 1. How to query the permissions of a role?A. System permissions contained in a roleSelect * from dba_sys_privs

After the memory usage of apsaradb for Redis reaches the value set by maxmemory, the gamer data cannot be written. Let's talk about our company's redis application scenarios. Currently, online games use redis as the front-end cache of MongoDB to

MySQL and Oracle Database concat () Functions I. Different Function Parameters MySQL supports concatenation of multiple strings: CONCAT (str1, str2 ,...) Oralce only supports concatenation of two strings. To splice multiple strings, you can use

Memory Usage Analysis of sorted sets and lists in Redis Before getting started, you need to understand several definitions: dictionary, compressed list, and skip table. Dictionary: a common data structure, the key-value structure. Common

Install a Linux Binary Package for MongoDB MongoDB is an open-source document database that provides common performance, high availability, and automatic scaling. The record in MongoDB is a document, which is a structure consisting of fields and

MongoDB uses replica set backup to add new secondary replica members Problem description: In the production environment, when the read Pressure on secondary replica members is high, you can relieve the pressure by adding new secondary replica

SQL serveri does not need a cursor, so it is suitable for instances with circular DML (update delete insert), serveridml SQL serveri does not need a cursor, so it is suitable for instances in the case of circular DML (update delete insert ). use

[ORACLE] Method for adding or deleting disk members to an ASM disk, asmdisk**************************************** ********************************* *** Original article: blog.csdn.net/clark_xu Xu changliang's column*********************************

Difference between inner join and left join in SQL statements: innerjoin The project requirement is changed. I wrote a query SQL statement, which needs to be modified. I haven't changed it for a long time. Finally, I want to join the SQL statement ),