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How to deal with MySQL database-related exceptions, I believe that many inexperienced people do not know what to do, so this paper summarizes the causes of the problem and solutions, through this article I hope you can solve this problem.

As we all know, exceptions are inevitable in the use of any database. The following editor to explain the MySQL database-related exceptions how to deal with?

Problem 1: StartingMySQL..Managerofpid-filequitwithoutupdatingf [failed] StartingMySQL...Managerofpid-filequitwithoutupdating [failed] when starting mysql

Solution:

The first kind:

1. Delete the numeric suffix of all temporary files in the / usr/local/mysql/data/mysql-bin.* folder.

two。 Restart mysql (restart after binary installation) servicemysqldstart.

The second kind:

Edit / etc/my.cnf add:

[mysqld] datadir=/var/lib/mysql

The MySQL server stores the database in the directory defined by the datadir variable.

Kill after checking the existing process:

Ps-aux | grepmysql8016pts/200:00:00mysqld_safe8037pts/200:00:00mysqld

Restart mysql.

The third kind:

Comment out in / etc/my.cnf

Skip-federated= > # skip-federated

The fourth kind:

Sometimes this error occurs when datadir=/var/lib/mysql is set in / etc/my.cnf to restart mysql.

If not set separately, the mysql default data directory is under the mysql installation directory.

Problem 2: FATALERROR:Couldnotfind./bin/my_print_defaults appears when the system is allowed to generate its own library.

Solution: / usr/local/mysql/scripts/mysql_install_db--user=mysql--basedir=/usr/local/mysql--datadir=/usr/local/mysql/data

Question 3: mysql_connect () [function.mysql-connect]: Can'tconnecttolocalMySQLserverthroughsocket'/var/lib/mysql/mysql.sock' (13) / eccore/model/mysql.php94 or StartingMySQL/etc/init.d/mysql:line327:--socket=/var/lib/mysql/mysql.sock.

Solution:

1 > add the following code to let mysql apply this file to the tmp folder, which defaults to / var/lib/mysql/mysql.sock.

Modify / etc/my.cnf

[mysql] socket=/tmp/mysql.sock

2 > go to / tmp folder to create mysql.sock

Touchmysql.sock

3 > restart mysql

/ etc/init.d/mysqldrestart

How to deal with related exceptions in MySQL database

Question 4: the following error occurred when host A mysql accesses host B mysql:mysql-uroot-proot-P3306-h292.168.100.52: ERROR2003 (HY000): Can'tconnecttoMySQLserveron'192.168.100.52'

Solution:

1. The server should be accessible on the network (public network). If there is a firewall, open port 3306 (the default listening port for MySQL).

Turn off all firewalls / etc/rc.d/init.d/iptablesstop

Join the rule vim/etc/sysconfig/iptables

two。 The easiest way to set up a remote user on the mysql server is

GrantALLPRIVILEGESon*.*tousername@ "" identifiedby "root"

Question 5: there are several situations in which MySQLserverhasgoneaway occurs.

Solution:

1. Applications (such as PHP) execute batch MYSQL statements for a long time.

Solution:

Add or modify the following two variables in the my.cnf file:

Wait_timeout=2880000interactive_timeout=2880000

For a specific description of the two variables, you can google or refer to the official manual.

If you cannot modify my.cnf, you can set CLIENT_INTERACTIVE when connecting to the database, such as:

Sql= "setinteractive_timeout=24*3600"; mysql_real_query (...)

2. Execute a SQL, but the SQL statement is too large or contains BLOB or longblob fields. For example, the processing of picture data.

Solution:

Add or modify the following variables in the my.cnf file:

Max_allowed_packet=10M (you can also set the size you want)

The max_allowed_packet parameter is used to control the maximum length of its communication buffer.

After reading the above, have you mastered how to deal with MySQL database-related exceptions? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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