Database Administrator

First recognized undo type Log System The log system is the basic mechanism to ensure that the database management system correctly executes transactions. Based on different functions, the log system can be divided into undo and redo. This article

Deep understanding of MySQL Cluster Index Clustered index is not a separate index type, but a data storage method. When a table has a clustered index, its data rows are actually stored in the index's leaf page. The term "clustering" indicates that

SYSTEM tablespace AUD $ solution to excessive space usage Problem: The SYSTEM tablespace usage exceeds 99%. During the preliminary design, the SYSTEM tablespace is fixed to 10 GB and cannot be automatically expanded.1. query the usage of the SYSTEM

How MySQL achieves transaction isolationReview Among the many storage engines of MySQL, only InnoDB supports transactions. The transaction isolation level mentioned here refers to the transaction isolation level under InnoDB. Read not committed: one

PL/SQL Developer connects to the local Oracle 11g 64-bit database and shortcut key settings1. log on to PL/SQL Developer The installation steps of Oracle Database and PL/SQL Developer are omitted here. Note that the PL/SQL Developer software should

Semi-synchronous replication in MySQL master-slave Replication Experiment MySQL uses the plug-in provided by Google to complete the semi-synchronous replication model; the physical machine is still Windows 7, and the virtual machine is CentOS

ORA-28000: the account is locked to check which specific IP address causes Check the default system policy and the account will be locked after 10 consecutive verification errors. SQL> select resource_name, limit from dba_profiles where profile =

MySQL slow query log analysis tool mysqldumpslow Mysqldumpslow is a log analysis tool that comes with mysql. As the name suggests, mysqldumpslow is used to query SQL statements that are slow in query. This analyzes the causes of slow SQL query

SQL Server database replicationIntroduction: SQL replication can solve many problems in running database-driven applications. Because the sending/subscription mode is not easy to understand, complicated scripting languages and monitoring and

Solution for deleting the root user of MySQL by mistake in Linux I started to be unfamiliar with the Linux interface. Maybe I accidentally deleted the root user. What should I do? 1. # killall mysqld to kill all mysql Processes 2. # mysqld_safe --

Analysis on the reason why the RMAN backup file is much larger than the database size When talking with the customer, the customer proposed that the database size is only 40 GB, but the file backed up by RMAN is 80 GB, And the DUMP file exported by

Compare the date difference between MySQL and Oracle by using a create statement Today, a developer submitted an SQL change and found a problem during deployment.A statement is a simple create statement.Create table 'test _ user '('Openid' varchar (6

Sql9.3 graphic tutorial for installing PostgreSQL9.3 in CentOS 7, postgresql9.3 For example, this blog record the entire process of installing PostgreSQL in CentOS 7 and the database configuration. in Linux, PostgreSQL can be installed in two ways: 1

HBase vs. MongoDB vs. MySQL vs. Oracle vs. Redis, the primary key of the three major open-source NoSQL databases, the two mainstream traditional SQL databases, nosqlredismongodb HBase vs. MongoDB vs. MySQL vs. Oracle vs. Redis, the primary key

Install adventure and northwind Sample Database, adventurenorthwind There are a lot of information on AdventureWorks database installation for help on the Internet. You can also find many answers to this question in baidu and google, but some of the

Onsql and MySQL Start and Stop scripts and onsqlmysql scripts Start and stop onesql. A total of four parameters are {start | stop | restart | status}. You only need to slightly change the three file paths in the header to start and stop a single

[Reference The Source: http://blog.csdn.net/bhq2010/article/details/12200533] The vs debugging pg source code used in the pg kernel source code parsing class. VS is easy to use, but it is a little troublesome to configure the debugging environment.

In the past few days, I have watched starring Fan Wei, and once again I have enjoyed Fan Wei's superb acting skills, especially the cool expression. After reading this, I think of the tracking and anti-tracking technologies in SQLServer. I think

This article describes Oracle cross-platform migration, such as migrating data from Oracle to other types of databases, but retaining the original structure. This reduces the workload of DBAs. I hope this article will help you better understand

NOSQL systems generally advertise a feature, that is, good performance. Why? After so many years of development in relational databases, various optimization work has been done very deeply. NOSQL systems generally use relational database technology.