mysql server doesn't recognize changes in my.cnf - mysql

I have installed mysql server and mysql client with bundle in Centos 7. mysql server's port is displayed as 0. I want to give specific port to it. For this purpose, I have changed /etc/my.cnf with below;
port=4545
After changes, I've restarted the service. But it's start with skip-networking as ON. I have also tried to change skip-networking to OFF but didn't accomplish.
I have also tried mysql_secure_installation after changes but got below error :
Failed! Error: The MySQL server is running with the
--skip-grant-tables option so it cannot execute this statement
How can i solve this?
Thanks for answering

I have solved my question with below;
systemctl stop mysqld
systemctl daemon-reload
systemctl set-environment MYSQLD_OPTS="--skip-networking=OFF"
After this I have started service again.
systemctl start mysqld

Related

can't connect to any database after upgrading open-ssh

I upgraded open ssh with this command: sudo apt-get upgrade openssh-server
I rebooted the server and after that, I can't connect to any database (Wordpress database, you'll database, phpmyadmin database)
for Wordpress I get: Error establishing a database connection
for yourls I get: Incorrect DB config, or could not connect to DB
for phpmyadmin I get: mysqli_real_connect(): (HY000/2002): No such file or directory
WHat's the solution please!
I think that it's a mysql problem because it doesn't not start and when I check mysql.service I find that's failed
WHat's the solution please!
This is logs:
This is the error log /var/log/mysql/error.log
error.log page 2
mysql status
systemctl status mysql.service
journalctl -xe page 1
journalctl -xe page 2
journalctl -xe page 3
You can check MYSQL status by running following command
sudo /etc/init.d/mysql status
Or restart and try once
sudo /etc/init.d/mysql restart
If you still can not connect database you can change DB_HOST localhost to 127.0.0.1.
Finally, the solution was to go to: etc/mysql/mysql.conf.d/mysqld.cnf
I found mysqld.cnf permission set to 644
I change it to 777 and the MySQL works again.
I don't know why running the upgrade with this command
sudo apt-get upgrade openssh-server
changed many permissions to files and directories.
I think that 777 is too open, can I make a less permission without stoping MySQL? what permission do you advise me to both mysqld.cnf and my.cnf in those directories?
etc/mysql/mysql.conf.d/mysqld.cnf
and
etc/mysql/my.cnf
welcome,
Try the permission 640 (rw-r-----). That's the minimal permission required.

MySQL community server suddenly stopped working [duplicate]

My problem started off with me not being able to log in as root any more on my mysql install. I was attempting to run mysql without passwords turned on... but whenever I ran the command
# mysqld_safe --skip-grant-tables &
I would never get the prompt back. I was trying to follow these instructions to recover the password.
The screen just looks like this:
root#jj-SFF-PC:/usr/bin# mysqld_safe --skip-grant-tables
120816 11:40:53 mysqld_safe Logging to syslog.
120816 11:40:53 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
and I don't get a prompt to start typing the SQL commands to reset the password.
When I kill it by pressing CTRL + C, I get the following message:
error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'
Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!
If I retry the command and leave it long enough, I do get the following series of messages:
root#jj-SFF-PC:/run/mysqld# 120816 13:15:02 mysqld_safe Logging to syslog.
120816 13:15:02 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
120816 13:16:42 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
[1]+ Done mysqld_safe --skip-grant-tables
root#jj-SFF-PC:/run/mysqld#
But then if I try to log in as root by doing:
# mysql -u root
I get the following error message:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
I checked and /var/run/mysqld/mysqld.sock file doesn't not exist. The folder does, but not the file.
Also, I don't know if this helps or not, but I ran find / -name mysqld and it came up with:
/var/run/mysqld - folder
/usr/sbin/mysqld - file
/run/mysqld - folder
I don't know if this is normal or not. But I'm including this info just in case it helps.
I finally decided to uninstall and reinstall mysql.
apt-get remove mysql-server
apt-get remove mysql-client
apt-get remove mysql-common
apt-get remove phpmyadmin
After reinstalling all packages again in the same order as above, during the phpmyadmin install, I got the same error:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
So I tried again to uninstall/reinstall. This time, after I uninstalled the packages, I also manually renamed all mysql files and directories to mysql.bad in their respective locations.
/var/lib/mysql
/var/lib/mysql/mysql
/var/log/mysql
/usr/lib/perl5/DBD/mysql
/usr/lib/perl5/auto/DBD/mysql
/usr/lib/mysql
/usr/bin/mysql
/usr/share/mysql
/usr/share/dbconfig-common/internal/mysql
/etc/init.d/mysql
/etc/apparmor.d/abstractions/mysql
/etc/mysql
Then I tried to reinstall mysql-server and mysql-client again. But I've noticed that it doesn't prompt me for a password. Isn't it supposed to ask for an admin password?
Try this command,
sudo service mysql start
To find all socket files on your system run:
sudo find / -type s
My Mysql server system had the socket open at /var/lib/mysql/mysql.sock
Once you find where the socket is being opened, add or edit the line to your /etc/my.cnf file with the path to the socket file:
socket=/var/lib/mysql/mysql.sock
Sometimes the system startup script that launched the command line executable specifies a flag --socket=path. This flag could override the my.cnf location, and that would result in a socket not being found where the my.cnf file indicates it should be. Then when you try to run the mysql command line client, it will read my.cnf to find the socket, but it will not find it since it deviates from where the server created one. So, Unless you care where the socket resides, just changing the my.cnf to match should work.
Then, stop the mysqld process. How you do this will vary by system.
If you're super user in the linux system, try one of the following if you don't know the specific method your Mysql setup uses:
service mysqld stop
/etc/init.d/mysqld stop
mysqladmin -u root -p shutdown
Some systems aren't setup to have an elegant way to stop mysql (or for some reason mysql doesn't respond) and you can force terminate mysql with either:
One step: pkill -9 mysqld
Two step (least preferred):
Find the process id of mysql with either pgrep mysql or ps aux | grep mysql | grep -v grep
Assuming the process id is 4969 terminate with kill -9 4969
After you do this you might want to look for a pid file in /var/run/mysqld/ and delete it
Make sure the permissions on your socket is such that whatever user mysqld is running as can read/write to it. An easy test is to open it up to full read/write and see if it still works:
chmod 777 /var/run/mysqld/mysqld.sock
If that fixes the issue, you can tailor the permissions and ownership of the socket as needed based on your security settings.
Also, the directory the socket resides in has to be reachable by the user running the mysqld process.
This error occurs due to multiple installations of mysql.
Run the command:
ps -A|grep mysql
Kill the process by using:
sudo pkill mysql
and then run command:
ps -A|grep mysqld
Also Kill this process by running:
sudo pkill mysqld
Now you are fully set just run the following commands:
service mysql restart
mysql -u root -p
Have very well working mysql again
The solution is way easier.
First, you have to locate(in Terminal with "sudo find / -type s") where your mysql.sock file is located. In my case it was in /opt/lampp/var/mysql/mysql.sock
Fire up Terminal and issue
sudo Nautilus
This starts your Files manager with super user privileges
From Nautilus navigate to where your mysql.sock file is located
Right click on the file and select Make Link
Rename the Link File to mysqld.sock then Right click on the file and Cut it
Go to /var/run and create a folder called mysqld and enter it
Now right click and Paste the Link File
Voila! You will now have a mysqld.sock file at /var/run/mysqld/mysqld.sock :)
Just Need to Start MySQL Service after installation:
For Ubuntu:
sudo service mysql start;
For CentOS or RHEL:
sudo service mysqld start;
There is a bug on Ubuntu with MySQL 5.6 and 5.7 where var/run/mysqld/ would disappear whenever MySQL service stopped or is rebooted. This prevents MySQL from running at all. Found this workaround, which isn't perfect, but at least it gets it running after stopping/reboot:
mkdir /var/run/mysqld/
chown mysqld /var/run/mysqld/
Make sure your inaccessible socket file path is same as '/var/run/mysqld/mysqld.sock', otherwise change the path as yours.
Stop the mysqld
$ sudo /etc/init.d/mysqld stop
If the process still runing;
$ sudo pkill -9 mysqld
Remove the mysql directory where socket going to create. For me it did not allowed to remove, so I had to forcefully remove.
$ sudo mkdir -p /var/run/mysqld
Set the ownership to the dirctory
$ sudo chown mysql:mysql /var/run/mysqld
Start mysql
$ sudo /etc/init.d/mysql start
Trying to connect mysql
$ sudo mysql -u dbuser -p
Okay just copy and paste these codes: This should be done in the terminal, inside a server, when your mysql database is not properly installed, and when you are getting this error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'.
Stop MySql
sudo /etc/init.d/mysqld stop
Restart it or start it
sudo /etc/init.d/mysqld restart or sudo /etc/init.d/mysqld start
Make a link like this and give it to the system
ln -s /tmp/mysql.sock /var/lib/mysql/mysql.sock
Run a secure installation which guides all the process you need to do to configure mysql
/usr/bin/mysql_secure_installation
I faced same error and found that it was due to upgradation of packages, So after restarting my system I resolved error.
I think due to sql libraries/ packages update that error occured, So try this if you are doing some upgrading :)
There is a lots of reason for this issue, but sometimes just restart the mysql server, it will fix the issue.
sudo service mysql restart
The answer of the user load step worked for me.
Sometimes is need edit the file in /etc/mysql/my.cnf add line to client
[client]
password = your_mysql_root_password
port = 3306
host = 127.0.0.1
socket = /var/lib/mysql/mysql.sock
Using XAMPP on ubuntu:
Create a folder called mysqld inside /var/run directory. You can accomplish that using the command sudo mkdir /var/run/mysqld.
Create a symbolic link to mysql.sock file that is created by the XAMPP server when it is started. You can use the command sudo ln -s /opt/lampp/var/mysql/mysql.sock /var/run/mysqld/mysqld.sock.
Note: The mysql.sock file is created when the server is started and removed when the server is stopped, so sometimes the link you created might appear to be broken but it should work as long as you have started the server using either sudo /opt/lampp/lampp start or any other means.
Start the server if it's not already running and try executing your program again.
Good luck! I hope you'll get away with it this time.
I think your MySQL server has not started. So start the server using one of the following commands.
#services mysql start
or
#/etc/init.d/mysql start
Why getting this error
I received new updates of mysql libraries so i updated my Kubuntu OS after that getting these errors.
Commands i tried and how i fixed it.
MySql-server is running correctly but when i tried to connect its giving
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'.
I checked /var/run/mysqld/mysqld.sock'. this directory.
My files did not existed.
I also tried these commands to connect but did not worked for me.
mysql -h 127.0.0.1 -P 3306 -u root -p
sudo service mysql start
After wasting round about 2 hours i found the solution
sudo apt-get clean
sudo apt-get update
sudo apt-get upgrade -f
After that everything fixed for me.
*Error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'
solutions
finally uninstall and reinstall mysql. **
sudo apt-get remove mysql-server
sudo apt-get remove mysql-client
sudo apt-get remove mysql-common
sudo apt-get remove phpmyadmin
then install again by
sudo apt-get install mysql-server-5.6
After this operation, 164 MB of additional disk space will be used.
Do you want to continue? [Y/n] Y press YES for complete installations
......
.......
At last you will get these lines....
Setting up libhtml-template-perl (2.95-1) ...
Setting up mysql-common-5.6 (5.6.16-1~exp1) ...
Processing triggers for libc-bin (2.19-0ubuntu6)
Processing triggers for ureadahead (0.100.0-16) ...
And then
root#ubuntu1404:~# mysql -u root -p (for every password first u
should use )
Enter password:
Note :Entered password should be same as the installation time
password of mysql(like .root,system,admin,rahul etc...)
Then type
USE rahul_db(database name);
Thanks.**
Temporary Solution
Maybe someone facing this problem. I am using Mysql Workbench on Ubuntu 14 and got this error.
mysqldump: Got error: 2002: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2) when trying to connect
Find your socket file by running sudo find / -type s, in my case it was /run/mysqld/mysqld.sock
So, I just created a link to this file in tmp directory.
sudo ln -s /var/run/mysqld/mysqld.sock /tmp/mysql.sock
Please note that this is a temporary solution since the file created will be under /tmp. See other answers for a permanent solution.
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
in /etc/my.cnf add this lines:
[client]
socket=/var/lib/mysql/mysql.sock <= this path should be also same as is[mysqld]
And restart the service with:
service mysql restart
this worked for me
This was mentioned a couple of times already, but this worked immediately for me:
service mysql restart
you can find mysqld.sock in /var/run/mysqld if you have already installed mysql-server
by sudo apt-get install mysql-server
I just had this problem on Ubuntu 14.10
Turns that mysql-server was no longer installed (somehow it had been removed) but I couldn't just install it because there were some broken packages and dependency issues/conflicts.
In the end I had to reinstall mysql
sudo apt-get remove mysql-client
sudo apt-get install mysql-server
I had the exactly same issue. After struggling for an hour, I found a way of correcting it without reinstalling mysql-common, mysql-client, mysql-server.
First of all, go to "/var/run/mysqld". You will find that the mysql.sock does not exist. Simply remove the entire mysqld directory and recreate it and provide it necessary privileges.
# rm -rf /var/run/mysqld && mkdir /var/run/mysqld && chown mysql /var/run/mysqld/
Now, Kill the mysql process in it's entirety. It might be possible that it will show you "waiting for page cleaner" on running "/etc/init.d/mysql status" command even after shutting down the service.
To completely close the service, use
# pkill -9 mysqld
Once the process is killed, try starting it again using
# /etc/init.d/mysql start
And you will see that it works good! And also there will be no issue in stopping it too.
In My case two mysqld processes were running..
killed the optional processs by using
pkill -9 mysqld
If you have a lot of databases and tables on your system, and if you have innodb_file_per_table set in my.cnf, then your mysql server might have run out of opened objects / files (or rather the descriptors for these objects)
Set a new max number with
open-files-limit = 2048
and restart mysql.
This approach might help when the socket is not created at all, but really this might not not be the real problem, there is an underlying problem.
My solution;
Ubuntu 18.04 (WSL)
/etc/mysql/my.cnf
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/
/etc/mysql/mysql.conf.d/mysqld.cnf
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
I changed the port. It's worked for me. You can write another port. Example 3355
I am using XAMPP on Ubuntu. I found this error when connecting database through terminal. I solve it without any configuration because default socket file path in XAMPP is written in "/opt/lampp/etc/my.cnf" as following:
[client]
#password = your_password
port = 3306
socket = /opt/lampp/var/mysql/mysql.sock
now you can connect just by giving this socket path parameter with mysql command on terminal like:
mysql -u root --socket /opt/lampp/var/mysql/mysql.sock
and it's done without any configuration.
If you don't want to type socket path everytime, then go for changing default path in my.cnf by "/var/run/mysqld/mysqld.sock". Provide permissions and restart mysql server.
Edit:
Recently I've installed Ubuntu 20.04 and trying to install MySQL server but my system were crashing and not working at all. So I've just completely removed MySQL and installed MariaDB. Its working like a charm without any problems.
Changing the host to 127.0.0.1 worked for me.
Edit the file in /etc/mysql/my.cnf and add the below mentioned line to the section: client
[client]
port = 3306
host = 127.0.0.1
socket = /var/lib/mysql/mysql.sock
After you are done with it. Execute the following command.
sudo service mysql start
I had similar problem on a CentOS VPS. If MySQL won't start or keeps crashing right after it starts, try these steps:
1) Find my.cnf file (mine was located in /etc/my.cnf) and add the line:
innodb_force_recovery = X
replacing X with a number from 1 to 6, starting from 1 and then incrementing if MySQL won't start. Setting to 4, 5 or 6 can delete your data so be carefull and read http://dev.mysql.com/doc/refman/5.7/en/forcing-innodb-recovery.html before.
2) Restart MySQL service. Only SELECT will run and that's normal at this point.
3) Dump all your databases/schemas with mysqldump one by one, do not compress the dumps because you'd have to uncompress them later anyway.
4) Move (or delete!) only the bd's directories inside /var/lib/mysql, preserving the individual files in the root.
5) Stop MySQL and then uncomment the line added in 1). Start MySQL.
6) Recover all bd's dumped in 3).
Good luck!
I uninstalled mysql in Ubuntu 16.04 https://askubuntu.com/questions/172514/how-do-i-uninstall-mysql
I reinstalled mysql
https://www.digitalocean.com/community/tutorials/how-to-install-mysql-on-ubuntu-16-04
This seemed to work.
First create dir /var/run/mysqld
with command:
mkdir -p /var/run/mysqld
then add rigths to the dir
chown mysql:mysql /var/run/mysqld
after this try
mysql -u root
You must install mysql-server
apt install mysql-server

mysql.sock does not exist error in fresh install of MySQL on Arch Linux

I'm trying to use MySQL on Arch Linux. it is already installed but this error comes up when I try to connect:
connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/run/mysqld/mysqld.sock' (2 "No such file or directory")'
I've looked for /etc/my.cfg but the file does not exist.
Something must have gone wrong during the installation.
How can I "purge" MariaDB and reinstall it?
If you're using archlinux it is a vital idea to understand the package manager (pacman). For the question about /etc/my.cfg you can run
pacman -Ql mariadb
there you will see that the file is actually called:
/etc/mysql/my.cnf
Arch linux will not configure the package for you, that is part of the arch philosophy. It will provide example configurations, and even provide you with a systemd unit file
usr/lib/systemd/system/mysqld.service
but it is your responsibility to ensure that the configuration is correct and actually start the daemon.
systemctl enable mysqld # add the unit file to the boot sequence
systemctl start mysqld # runs ExecStart= in the unit file
systemctl stop mysqld # kills the daemon
systemctl disable mysqld # remove unit from boot sequence
reinstall
Since the word reinstall is in the title of the question and someone might find this question thanks to that: To reinstall mariadb you simply do
pacman -S mariadb
pacman will reinstall a package that is already installed, there is no need to remove the package (for completeness, package removal happens with pacman -R)
as of 7-28-17 I had to do this on a new install. Newbie here might save someone some time. It was a real pain.
OK HERE IS THE DEAL!!!!!
INSTALL APACHE _ NO PROB
INSTALL MYSQL _PROBLEM
pacman -S mysql then before starting service
MUST UNCOMMENT INNODB IN:
nano /etc/mysql/my.cnf
then must initialize datadirectory before starting service:
mysql_install_db --user=mysql --basedir=/usr --datadir=/var/lib/mysql
You need to initialize the MariaDB data directory prior to starting
the service. This can be done with mysql_install_db command, e.g.:
mysql_install_db --user=mysql --basedir=/usr --datadir=/var/lib/mysql
Optional dependencies for mariadb
galera: for MariaDB cluster with Galera WSREP
perl-dbd-mysql: for mysqlhotcopy, mysql_convert_table_format and
mysql_setpermission
CNF file is /etc/mysql/my.cnf in Arch Linux.
One simple way I can reproduce your issue is when MariaDB is shut down. Sorry if it sounds dumb but as you did not mention it: is MariaDB started? sudo systemctl start mysqld.service
You should have a look at MariaDB logs to get some clue: journalctl _SYSTEMD_UNIT=mysqld.service (maybe paste some part if you still don't get what is going on).
This happens the first time you install MySQL and MariaDB. As grochmal pointed out, you have to set up configurations before first use. But, the user teckk sent these three links in the archlinux newbie corner:
https://wiki.archlinux.org/index.php/MariaDB
https://wiki.archlinux.org/index.php/MariaDB#Reset_the_root_password
https://bbs.archlinux.org/viewtopic.php?id=51981
In short, you have to run the command below before starting the service:
sudo mariadb-install-db --user=mysql --basedir=/usr --datadir=/var/lib/mysql
Optionally (recommended) you should improve the initial security by calling:
sudo mysql_secure_installation
Now you can start the service:
sudo systemctl start mariadb
Optionally, you could install and use a graphical front-end tool.
Carry on with setting up the configurations as described in the archwiki post on MariaDB Configuration.

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'

I have installed Centos7 update, removed MariaDB and done a fresh install of MySQL - additionally I have removed it and reinstalled it but everytime I connect to mysql -u root -p I get the titled error. Additionally I have looked at other tickets associated with this but still not making progress. If I run service mysqld restart it says "Redirecting to /bin/systemctl restart mysqld.service" and then just hangs. Really not a linux expert so not sure what is causing this?
I had the same problem and found out a few things after digging around. MariaDB is a drop-in replacement for mysql. On the new system, mysql is the MariaDB client (although I'm not clear on what that means). I checked to see if the service was running:
service mysqld status
which indicated:
Redirecting to /bin/systemctl status mysqld.service
mysqld.service
Loaded: not-found (Reason: No such file or directory)
Active: inactive (dead)
In other words, the mysqld service is not running.
Starting the service worked for me:
`systemctl start mariadb.service`
Now all the mysql commands work as expected.
To tie the last knot, enable the service at boot:
`systemctl enable mariadb.service`
Check the 'socket=' entry in your /etc/my.cnf within the [mysqld] section:
[mysqld1]
socket = /tmp/mysql.sock1
An alternate method is to provide the '-hhost' & '-Pport' parameters to the 'mysqladmin' or 'mysql' commands, to avoid using the socket.
mysql -u user -hservername -P3006 -p -Dschema
mysqladmin -u user -p -hhostname -Pport
Removing the dir fixed it - deleted the dir (with rm -rf "dir name") and then unintalled mysql "yum remove mysql mysql-server" then reinstalled "yum install mysql-server" and ran "service mysqld start"
If you have this problem with the start mysql service hanging - check the logs /var/log/mysqld.log as suggested by Jeremiah.
If you look into the MariaDB log file, you may see that the issue is related to creating pid file. To solve it: create the PID directory then change its owner to mysql:mysql

Could not connect: Lost connection to MySQL server at 'reading initial communication packet', system error: 0

I am running a Rails app so now I am trying to remote connect to MySQL and I am getting this error:
Could not connect: Lost connection to MySQL server at 'reading initial communication packet', system error: 0
You might want to check your /etc/hosts.deny where:
ALL: ALL: DENY
or
mysqld: ALL: DENY
is your enemy.
Rebooting the server worked for me. No settings changes needed.
check from that host
shell> telnet IP 3306
If MySQL is up and reachable you'll see mysql version in telnet output.
Otherwise check firewall, etc until telnet succeeds.
Then I advice you first connect with native mysql client to exclude Rails from problem aria.
Enable remote access.
The MySQL server does not listen on the TCP port 3306 by default. To allow (remote) TCP connections, comment the following line in /etc/mysql/my.cnf:
skip-networking
Remember to edit /etc/hosts.allow by adding the following lines:
mysqld: ALL : ALLOW
mysqld-max: ALL : ALLOW
You need to edit your mysql Configuration file, by default the bind-adress is set to 127.0.0.1.
Open: /etc/mysql/my.cnf
Change the bind-adress to the ip you are going to use to connect yoursef to the database server.
Using OS X? Does this issue go away for a while after mysqld restart and then re-appear? Check mysql server logs when getting these errors. I'm seeing a bunch of entries like below:
2019-01-30T17:34:04.009979Z 0 [Warning] File Descriptor 1564 exceeded FD_SETSIZE=1024
This error points to potential solutions:
https://expressionengine.com/blog/mysql-5.7-server-os-x-has-gone-away https://wilsonmar.github.io/maximum-limits/
One of them is adding following setting to my.cnf
[mysqld]
table_open_cache=250
Nobody has seemed to answer this, and it appears to have re-emerged as an issue nearly 7 years after originally being filed. I saw this on Rails app running Capybara (using phantomjs), my integration specs (only) would intermittently fail with this.
Restarting the machine temporarily fixed the problem.
I then imploded my MySQL installation completely (see https://community.jaspersoft.com/wiki/uninstall-mysql-mac-os-x) and re-installed it using homebrew. The problem appears to have gone away but I will update this answer if it comes back.
to implode your MySQL install completely (from https://community.jaspersoft.com/wiki/uninstall-mysql-mac-os-x):
Open a terminal window
Use mysqldump to backup your databases to text files!
Stop the database server
sudo rm /usr/local/mysql
sudo rm -rf /usr/local/mysql*
sudo rm -rf /Library/StartupItems/MySQLCOM
sudo rm -rf /Library/PreferencePanes/My*
edit /etc/hostconfig and remove the line MYSQLCOM=-YES-
rm -rf ~/Library/PreferencePanes/My*
sudo rm -rf /Library/Receipts/mysql*
sudo rm -rf /Library/Receipts/MySQL*
sudo rm -rf /private/var/db/receipts/*mysql*
As we all know there are many different ways to install and configure mySQL dbms (database managment system) on our machines besides the fact we all run different OS (linux, osx, win$hit, etc)
In my case in particular i was getting
connect': Lost connection to MySQL server at 'reading initial communication packet', system error: 102 (Mysql2::Error)
BUT i did not even had /etc/hosts.deny i only had /etc/hosts because i installed mySQL on my OSX machine using simple GUI OSX app
MySQL instance status was NOT OK above's image is just a reference for MySQL OSX APP.
Simple server re-start solved the issue.(in my case had to reboot my machine but that involves rebooting the MySQL server)
I was finally able to reach my localhost instance just fine again, did not had to change, create single file.
Hope this helps, i see Malcolm's answer and comments and made me think it was good to post this.
OS: macOS
MySQL version: 5.7
Killed the current mysql service process
mysql.server stop
and started it again
mysql.server start
This solve the issue for me.
mysqld-max: ALL : ALLOW
solved the problem for me.
Thank you guys for your effort, I have found the solution, I was suppose to set Remote Connection to MySQLhere is the link for someone who got the same error
http://benrobb.com/2007/01/15/howto-remote-root-access-to-mysql/