MySQL

On-line MySQL server configuration file parsingInnodb_buffer_pool_sizeA very important parameter for configuring the InnoDB buffer pool, if the database has only the OH InnoDB table, the recommended configuration amount is 75% of total memorySelect

One: MySQL LockTwo: MySQL TransactionsThree: MySQL Isolation Level1.1 Why do you have a lock? Because the database wants to solve concurrency control problems. At the same time, there may be multiple clients manipulating a table's data or some data,

Are you still ashamed to read Ho Dengcheng's lock-processing analysis article?Still in because of the master of the clerical error, into a deep confusion?As long as you have more than 5.6.16 version of MySQL, lock monitor you deserve to have!Quick

Note: index (name,age) indicates that a federated index is established on the Name,age two column because indexes have a critical impact on database query performance, here are some of my summary and experience: a query can use only one index at a

Binary types include binary, VARBINARY, BIT, Tinyblob, BLOB, Mediumblob, Longblob binary (M) types, save bytes instead of characters, no character set limit, byte number is M, allow length of 0 ~m a fixed-length binary string. Less than the maximum

Background:long time to the computer, resulting in "delirious", accidentally in MySQL under the wrong operation of "revoke all on * * from ' root ' @ ' localhost '; ", this command means removing all permissions from the highest-privileged user root

Data backup data loss reason: storage media applause, user operation error (delete the entire database by mistake), the server completely paralyzed 1, the file replication needs to stop the Server service, before stopping, execution Flushtables

The string type char and Varchar1, char (m) m are the maximum length of the string, and the length is any value between 0~255 bytes, occupying a fixed byte. 2, varchar (M) length is any value between 0~65535 bytes. The actual number of bytes is

Originally used in Java read file processing format after the database, run, found that the efficiency is too low, 4G text, more than 40 million lines, estimated to take about 30 days to complete processing.Data format:Each line, XXXX | | | XXXXXXX |

exists on the appearance with loop-by-article query, each query will look at the exists conditional statement, when the conditional statement in exists can return the record row (regardless of the number of record lines, as long as can return), the

Title: MySQL Database delete duplicate dataBecause it is MySQL, other data crying commands are not available in MySQL. Don't assume that SQL scripts are useddelete from Table1where field1 in ( select field1 from table1 group by field1 having

First look at the example:1, delimiter $$2. Drop procedure if exists ' test_procedure ' $$3. CREATE procedure test_procedure (in puser_id varchar ($), in pitem_id varchar ($), out result INT)4. Begin5. Select id into result from train_tbl where user_

One, prepare the tool.Httpd-2.4.12-win32-vc9.zipPhp-5.4.40-win32-vc9-x86.zipPhpmyadmin-4.2.13.2-all-languagesmysql-5.6.23-winx64 Configuration Reference: http://blog.csdn.net/q98842674/article/details/12094777Second, the environment to build.1,

IntroductionThese days to do a task, compared to two data tables in the data, yesterday wrote a version of PHP, but considering that some machines do not have PHP or PHP does not compile MySQL extension, you can not use the MySQL series of functions,

There are two main ways to backup MySQL: Text Format backup: Command: mysqldumpDump Files: Dump fileMain content: Database structure and data (create Talbe/insert) Binary backup: This type of backup is done by copying files directly.

Would like to change the table type to MyISAM, but error, such as:650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/6C/23/wKioL1VAuHHASEVcAAC6tPb2S0E109.jpg "title=" QQ Wubi not named. png "alt=" wkiol1vauhhasevcaac6tpb2s0e109.jpg "/>Cause

Reference: http://www.cnblogs.com/villion/archive/2009/07/23/1893765.html#3031899MySQL optimization can mainly consider the following four aspects:1. Database design:This is from the big aspect, the architecture aspect to design the database,

[MySql fast insertion of large data volumes and statement optimization] INSERTStatement speed The time required to insert a record is composed of the following factors, and the number indicates the approximate proportion: Connection: (3) Send the

MySQL changes the storage engine of database tables MySQL changes the storage engine of database tables 1. view the original storage engine of the table Show create table user; 'User', 'create TABLE 'user' (\ n' id' int (11) not null default

(18) partitions in mysql (after development)Overview Previously, when I saw the partition, I squeezed it out, so it was too big. Yesterday, I finally learned what partitioning is, but that is also the case. Today, we can sum up that good memory is