mysql installation:
Using the command
yum list mysql-server When installing mysql, I found that there is no mysql package. At this time, we need to download a
Download package
wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm
Download is complete, install the mysql-community-release-el7-5.noarch.rpm package
sudo rpm -ivh mysql-community-release-el7-5.noarch.rpm
Install mysql
sudo yum install mysql-server
Wait for the installation to complete….
Then select Y
After the installation is complete, mysql does not have a password and needs to be reset.
mysql -u root
ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)
Solution:
1. The mysql service is not running normally:
Since the mysql socket file is created when the mysqld service starts, if the mysqld service does not start normally, the socket file will naturally not be created, and of course the socket file will not be found. To determine whether the mysql service is started, we can use the following command:
# 1. Is the port open? [[email protected] ~]# lsof -i:3306 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME mysqld 12207 mysql 14u IPv4 52350 0t0 TCP *:mysql (LISTEN) # 2. Is the mysqld service running? [[email protected] ~]# service mysqld status mysqld (pid 4717) is running...
2. The socket file path is incompletely set in the configuration file:
This is generally caused by us modifying the mysql configuration “/etc/my.cnf”. For example, we modified the “socket” parameter under the “[mysql]” option in the configuration file without specifying the “socket” parameter of the “[client]” and “[mysql]” options, causing mysql to use the default socket file location. Looking for a socket file, causing this error to occur as the socket file is not found.
1. The mysql service is not running normally:
If the service is not started, we can run “service mysqld start” to start the service. If the service cannot be started, check the mysql service log to find the cause and solve it before starting it.
[[email protected] ~]# service mysqld start Starting mysqld: [OK] [[email protected] ~]# lsof -i:3306 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME mysqld 14109 mysql 10u IPv4 247183583 0t0 TCP *:mysql (LISTEN) [[email protected] ~]# service mysqld status mysqld (pid 14109) is running...
2. Improve the mysql configuration file:
If it is confirmed that the mysql service is running normally and the error in the article title is prompted, then it is a problem with the “/etc/my.cnf” configuration file. The solution is to modify the “/etc/my.cnf” configuration file, add the “[client]” option and the “[mysql]” option in the configuration file, and use the “socket” parameter value under these two options, and ” The “socket” parameter value under the “[mysqld]” option points to the same socket file path. as follows:
[mysqld] datadir=/storage/db/mysql socket=/storage/db/mysql/mysql.sock ...omit n lines... [client] default-character-set=utf8 socket=/storage/db/mysql/mysql.sock [mysql] default-character-set=utf8 socket=/storage/db/mysql/mysql.sock
Original address: http://www.aiezu.com/db/mysql_cant_connect_through_socket.html
If the problem still cannot be solved, try the following:
Check below things to fix the issue Check the permission of mysql data dir using below command # ls -ld /var/lib/mysql/ Check the permission of databases inside mysql data dir using below command # ls -lh /var/lib/mysql/ Check the listening network tcp ports using below command # netstat -ntlp Check the mysql log files for any error using below command. # cat /var/log/mysql/mysqld.log Try to start mysql using below command # mysqld_safe --defaults-file=/etc/my.cf
change Password:
# mysql -uroot -p
Enter password: [Enter the original password] (If you set the root password for the first time after installing mysql, just press Enter)
mysql>use mysql;
mysql> update user set password=password("123456") where user='root';
mysql> flush privileges;
mysql> exit;
How to configure mysql to allow remote connections
By default, mysql only allows local login. If you want to enable remote connections, you need to modify the /etc/mysql/my.conf file.
1. Modify /etc/mysql/my.conf
Find the line bind-address = 127.0.0.1
Just change it to bind-address = 0.0.0.0
2. Grant permissions to users who need to log in remotely
1. Create a new user to remotely connect to the mysql database
mysql>use mysql; mysql>create user luffy IDENTIFIED by '123456'; //identified by will encrypt the plain text password and store it as a hash value<br> mysql>grant select,delete,update,insert on *.* to 'luffy'@'%' identified by '123456' ; mysql>flush privileges;
Allow computers with any IP address (% means allow any IP address) to use the luffy account and password (123456) to access this mysql server.
2. Support root users to allow remote connection to mysql database
mysql>grant all privileges on *.* to 'root'@'%' identified by '123456' with grant option; mysql>flush privileges;
3. View system users
PS. If you still can’t connect remotely, you can refer to:
https://jingyan.baidu.com/article/380abd0a3aef431d90192c33.html
mysql installation 2
1. Download the mysql installation package mysql-5.7.23-linux-glibc2.12-x86_64.tar.gz
2. First cd /usr/local: and then decompress tar -zxvf mysql-5.7.23-linux-glibc2.12-x86_64.tar.gz
After decompression, you can change the decompressed file name to mysql for the convenience of subsequent operations:
mv mysql-5.7.23-linux-glibc2.12-x86_64 mysql
3. Then go to the support-files directory and copy my.cnf to /etc/my.cnf (automatically read when mysqld starts) cp my-default.cnf /etc/my.cnf
The latest version no longer has the file my-default.cnf.
my.cnf
[client] loose_default-character-set = utf8<br>socket = /usr/local/mysql/data/mysql.sock<br> [mysqld] basedir = /usr/local/mysql datadir = /usr/local/mysql/data port=3306 #server_id = 1 socket = /usr/local/mysql/data/mysql.sock expire_logs_days = 7 innodb_file_per_table innodb_buffer_pool_size = 2G innodb_thread_concurrency = 24 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 32M innodb_log_file_size = 256M innodb_log_files_in_group = 3 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 wait_timeout = 60 interactive_timeout = 7200 skip-name-resolve character-set-server=utf8 back_log = 50 max_connections = 3000 max_connect_errors = 32 max_allowed_packet = 32M binlog_cache_size = 8M max_heap_table_size = 512M tmp_table_size = 64M key_buffer_size = 16M read_buffer_size = 2M read_rnd_buffer_size = 8M bulk_insert_buffer_size = 64M sort_buffer_size = 4M join_buffer_size = 2M thread_cache_size = 64 thread_stack = 192K query_cache_type = 1 query_cache_size = 256M query_cache_limit = 2M ft_min_word_len = 2 default_storage_engine = INNODB #default_table_type = INNODB transaction_isolation = REPEATABLE-READ lower_case_table_names = 1 #log_slow_queries slow_query_log long_query_time = 2 log-short-format myisam_sort_buffer_size = 128M myisam_max_sort_file_size = 10G myisam_repair_threads = 1 [mysqldump] quick max_allowed_packet = 32M routines single-transaction hex-blob skip-comments complete-insert skip-disable-keys skip-add-locks skip-lock-tables [isamchk] key_buffer = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [myisamchk] key_buffer = 512M sort_buffer_size = 512M read_buffer = 8M write_buffer = 8M [mysqlhotcopy] interactive-timeout # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
4. Copy mysql.server to the /etc/init.d/ directory [The purpose is to achieve the automatic execution effect at boot]
Execute command: cp mysql.server /etc/init.d/mysql (mysql is the service name)
5. Modify the /etc/init.d/mysql parameter vi /etc/init.d/mysql to give 2 directory locations basedir=/usr/local/mysqldatadir=/usr/local/mysql/data
6. For security and convenience, create a dedicated user for operating the database
1), groupadd mysql #Create a mysql group
2), useradd -r -g mysql mysql #Create a mysql user and put the user in the mysql group
3), passwd mysql #Set a password for the mysql user
4). Change the owner of the directory /usr/local/mysql chown -R mysql:mysql /usr/local/mysql/
Initialize mysql database
First go to the bin directory of mysql
1. Initialization./mysqld –initialize –user=mysql –basedir=/usr/local/mysql –datadir=/usr/local/mysql/data
A data directory is generated, which means that the database has been initialized successfully and the root user of mysql has generated a temporary password: xxxxx (it is best to record this temporary password first)
The following problem encountered is caused by operation 1, which was not executed
Fatal error: Can’t open and lock privilege tables: Table ‘mysql.user’ doesn’t exist
2. Encrypt the database./mysql_ssl_rsa_setup –datadir=/usr/local/mysql/data
3. Start mysql (in order to prevent the process from being stuck, you can add & after the command to start mysql to indicate that the process is running in the background)./mysqld_safe –user=mysql &;
4. Check ps -ef|grep mysql
If the above processes are found, it means the startup is successful.
Step 5: Enter the client
1. Log in ./mysql -uroot -p and press Enter and enter the previous temporary password 2. Change the password set password=password(‘new password’);
mysql: command not found
Solution: # ln -s /usr/local/mysql/bin/mysql /usr/bin
mysql uninstall:
1. Use the following command to check the current installation of mysql and find out whether mysql has been installed before
rpm -qa|grep -i mysql
You can see it as shown in the figure below:
2. Stop the mysql service and delete the previously installed mysql
Delete command: rpm -e –nodeps package name
rpm -ev MySQL-client-5.5.25a-1.rhel5 rpm -ev MySQL-server-5.5.25a-1.rhel5
If you are prompted with a dependency package error, try using the following command
rpm -ev MySQL-client-5.5.25a-1.rhel5 --nodeps
If an error message is displayed: error: %preun(xxxxxx) scriptlet failed, exit status 1
Then try the following command:
rpm -e --noscripts MySQL-client-5.5.25a-1.rhel5
3. Find the directory of the previous version of mysql and delete the files and libraries of the old version of mysql
find / -name mysql
The search results are as follows:
find / -name mysql /var/lib/mysql /var/lib/mysql/mysql /usr/lib64/mysql
Delete the corresponding mysql directory
rm -rf /var/lib/mysql rm -rf /var/lib/mysql rm -rf /usr/lib64/mysql
The specific steps are as shown in the figure: Find the directory and delete it
Note: /etc/my.cnf will not be deleted after uninstallation and needs to be deleted manually.
rm -rf /etc/my.cnf
4. Check again whether the machine has mysql installed
rpm -qa|grep -i mysql
Reference address: https://www.cnblogs.com/wolf-sun/p/5655439.html
Reference address: https://www.cnblogs.com/nicknailo/articles/8563456.html
Reference address: https://www.aliyun.com/jiaocheng/133867.html?spm=5176.100033.1.15.22996b04YjkV5D