Database Administrator

CentOS6 change the MySQL data storage location When mysql is installed using yum, the default data is stored in/var/lib/mysql. Generally, to ensure data security, we recommend that you store the mysql database data files in the directory of the

Differences between statements for querying by page in Oracle, MySQL, and SQL Serve ★First, define the parameters to be used in the paging statement: Int currentPage; // current pageInt pageRecord; // number of records displayed per pageTake the

MySQL alter table storage engine (myisam innodb) View the supported database engines and default database engines of the current MySQL database 123456789101112131415 mysql> show engines;+--------------------+---------+-------------------

Simple use of MySQL event -- View the create information of the event Show create event event_test; -- View the event status in a schema SELECT event_schema, event_name, status from information_schema.events WHERE event_schema = 'xxxx'   -- Check

Error Caused by Double Type Precision Scenario Description R & D colleagues asked me to round the value of a double type field to keep two decimal places. In mysql, round (col, 2) can be rounded to five and keep two decimal places, but the magic

CentOS 6.5 install MySQL-5.5 via yum 1. Install the yum source for the mysql-5.5 rpm -ivh http://repo.mysql.com/yum/mysql-5.5-community/el/6/x86_64/mysql-community-release-el6-5.noarch.rpm 2. Modify the installed yum Source Edit the/etc/yum. repos.

Solution to Oracle 11gR2 listener startup error in CentOS7 An error occurred while starting the Oracle listener: [Oracle @ localhost ~] $ Lsnrctl start LSNRCTL for Linux: Version 11.2.0.1.0-Production on 12-APR-2016 00:27:54 Copyright (c) 1991,200 9,

MySQL pressure test tool-mydbtest PrefaceThis article introduces mydbtest (mydbtest_linux64.bin, compiled by Lou Fang Xin Da Niu), a tool for database stress testing without installation ). this stress testing software is different from common

MySQL slow query methods For troubleshooting and identifying performance bottlenecks, the most common problems are slow queries in MySQL and queries that do not have to use indexes. ========================================================== =========

Install Redis in CentOS6.4 First, we will introduce the Redis database. Redis is a memory database for "key/value" pairs of data types, which can meet our needs for reading and writing massive data.1) redis keys can only be strings; 2) redis values

MySQL force operation and order by usage We use hint commonly used in MySQL for detailed parsing. If you use Oracle frequently, you may know that Oracle has many hincvt features and provides many methods to optimize SQL statements. Similarly,

MySQL High Availability LVS + Keepalived + MySQL1. Architecture Diagram  Note: (1) Mysql needs to remove the bind-address Configuration; otherwise, virtual ip access cannot be implemented. (2) Disable all linux firewalls:/sbin/iptables-F (may be

Import (Restore) Oracle dmp files to different tablespaces and different users Copy A dmp backup file from the production environment, build a test environment on another computer, and run the imp command to import the dmp file with the following

Simple Test of Oracle 11g flash back Archiving The new features in Oracle 11g flash back archive provide a possibility for custom query of historical data. After learning this feature, I found that it is clear and easy to use. If used properly, it

Oracle imports the local dmp backup file into the local Oracle database. Oracle imports the local dmp backup file into the local Oracle database. Import syntax Imp usename/password @ SID full = y file = d: \ data \ xxxx. dmp ignore = y Import

Subscription and release of apsaradb for Redis Document directory 1. Why subscription distribution? 2. Subscription publishing in Redis 3. Redis producer consumer 4. Subscription and release in Redis 5. Java Jedis's pitfalls Why subscription

MySQL character collation (garbled) Problem Solving 1. Create a MySQL database 1 CREATE DATABASE `test`2 CHARACTER SET 'utf8'3 COLLATE 'utf8_general_ci'; Create a table 1 CREATE TABLE tp_wechatlocation 2 ( 3 ID INT NOT NULL AUTO_INCREMENT, 4

MySQL improves Insert Performance The time required to insert a record is composed of the following factors, and the number indicates the approximate proportion:• Connection: (3)• Send a query to the server: (2)• Analysis query: (2)• Insert record: (

Features introduced by Oracle 11g ASM 1.1 new features introduced by 11g ASM that affect ManagementThe following features will not be supported when the 10G version of ASM is maintained. However, most features have little impact on ASM maintenance. 1

MySQL Optimization TechnologyIntroduction The static page technology can cache dynamic data, but sometimes you still need to request the database. Therefore, database optimization is indispensable.Optimization ideas DESIGN: storage engine, field,