Database Administrator

Destructive Testing of dual tables With regard to dual table destructive testing, since it is a destructive test, it needs to be determined that this test is limited to testing or personal learning, and some SQL statements may seem extremely simple,

The SEGMENT_SIZE does not change after the TRUNCATE TABLE In the test environment, historical transaction tables can be cleared and only the table structure needs to be retained. Therefore, we wanted to clean up the space through TRUNCATE. We found

Install and use the MySQL Performance Testing Tool sysbench We need to use AWS and Azure MySQL services at work. We need to test and compare the performance of the two cloud services. As a result, Baidu + google began to search for performance

Solution to MySQL startup failure due to insufficient memory 1. Failed to start MySQL. Check the error log/var/log/mysql/error. log. 2. The main error messages are as follows: [ERROR] InnoDB: mmap (136151040 bytes) failed; errno 12[ERROR]

Microsoft introduced a new tool to help MySQL users migrate their data to Microsoft's SQL Server database. This tool is called the SQL Server migration assistant (SSMA ). The future of MySQL was unknown due to the Oracle-SUN purchase case. Microsoft

Database index advantages and disadvantages Why create an index? This is because creating an index can greatly improve the system performance.First, you can create a unique index to ensure the uniqueness of each row of data in the database

How can I return the id of the inserted data when mybatis performs the insert operation ?, Mybatisinsert 1. useGeneratedKeys = "true" to obtain the auto-growth ID. Only the databases with auto-growth mode are supported (mysql, mssql, etc., but

SQL primary key constraints and foreign key constraints, SQL primary key constraintsPrimary key constraint SQL PRIMARY KEY constraint The primary key constraint uniquely identifies each record in the database table. The primary key must contain a

Getting started with mongodb installation and getting started with mongodb--- 1. Disable NUMA In procRpm-qa | grep numactlYum install-y numactl# Echo 0>/proc/sys/vm/zone_reclaim_mode# Sysctl-w vm. zone_reclaim_mode = 0--- 2. Modify the maximum

In this Document   Goal   Fix   References Applies to: Oracle Server-Enterprise Edition-Version 11.2.0.1 and later Information in this document applies to any platform. Goal This document

Mysql, sqlsever, oracle, redis, mongo, postgres and other database backup and recovery commands, sqlseverredis The following is a simple example of how to back up and restore each database. For more detailed parameters and configurations, refer to

Redis document translation _ LRU cache, redis document _ lruUsing Redis as an LRU cache uses Redis as the LRU cacheSource: http://blog.csdn.net/column/details/redisbanli.htmlWhen Redis is used as a cache, sometimes it is handy to let it

MongoDB BASICS (9) sharding and mongodb Basics Sharding stores data on multiple servers. Mongodb uses sharding to support deployment of very large datasets and high throughput operations. The capabilities of a single server are limited in various

When a blocking txn id for DDL wait event occurs on Oracle 11gR2, 11gr2txn This article is the original article, reproduced please indicate the source: http://blog.csdn.net/msdnchina/article/details/44726875   In a recent case (oracle db of version 1

Data Control Language DCL) Data Control Language (DCL) is a statement used to set or change database user or role permissions. These statements include GRANT, DENY, REVOKE, and other statements. By default, only members of sysadmin, dbcreator,

Blue growth note-chasing DBA (14): unforgettable "Cloud" end, initial hadoop deployment, dbahadoop Original Works are from the blog of "Deep Blue blog". You are welcome to repost them. Please indicate the source when you repost them. Otherwise, the

CVE-2015-0235 lab record, cve-2015-0235 labAll-in-One and linux Server vulnerability analysis and repair! LINUX: 5.X 64 cell storage: 11.2.3.1.1# Patch packages required for vulnerabilities:Glibc-2.5-123.0.1.el5_11.1.i686.rpmGlibc-2.5-123.0.1.el5_11.

Node. js mongodb ReplSet, node. jsmongodb With the rise of web, applications with high concurrency and large data size have increasingly obvious performance requirements for Rapid database response. traditional relational databases are somewhat weak

Atitit. mysql oracle with as mode temporary table mode CTE statement, reduce the subquery structure mssql SQL server..., atitit. mysqlcte Atitit. Use of the CTE statement in the temporary table mode of mysql oracle with as mode to reduce the

Manage Azure SQL database authorization Security When planning the deployment of Microsoft Azure SQL Database, you must consider all the security measures that need to be implemented in the deep defense policy. In the previous article, we have