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I'm running a server at my office to process some files and report the results to a remote MySQL server.
The files processing takes some time and the process dies halfway through with the following error:
2006, MySQL server has gone away
I've heard about the MySQL setting, wait_timeout, but do I need to change that on the server at my office or the remote MySQL server?
I have encountered this a number of times and I've normally found the answer to be a very low default setting of max_allowed_packet.
Raising it in /etc/my.cnf (under [mysqld]) to 8 or 16M usually fixes it. (The default in MySql 5.7 is 4194304, which is 4MB.)
[mysqld]
max_allowed_packet=16M
Note: Just create the line if it does not exist
Note: This can be set on your server as it's running.
Note: On Windows you may need to save your my.ini or my.cnf file with ANSI not UTF-8 encoding.
Use set global max_allowed_packet=104857600. This sets it to 100MB.
I had the same problem but changeing max_allowed_packet in the my.ini/my.cnf file under [mysqld] made the trick.
add a line
max_allowed_packet=500M
now restart the MySQL service once you are done.
I used following command in MySQL command-line to restore a MySQL database which size more than 7GB, and it works.
set global max_allowed_packet=268435456;
It may be easier to check if the connection exists and re-establish it if needed.
See PHP:mysqli_ping for info on that.
There are several causes for this error.
MySQL/MariaDB related:
wait_timeout - Time in seconds that the server waits for a connection to become active before closing it.
interactive_timeout - Time in seconds that the server waits for an interactive connection.
max_allowed_packet - Maximum size in bytes of a packet or a generated/intermediate string. Set as large as the largest BLOB, in multiples of 1024.
Example of my.cnf:
[mysqld]
# 8 hours
wait_timeout = 28800
# 8 hours
interactive_timeout = 28800
max_allowed_packet = 256M
Server related:
Your server has full memory - check info about RAM with free -h
Framework related:
Check settings of your framework. Django for example use CONN_MAX_AGE (see docs)
How to debug it:
Check values of MySQL/MariaDB variables.
with sql: SHOW VARIABLES LIKE '%time%';
command line: mysqladmin variables
Turn on verbosity for errors:
MariaDB: log_warnings = 4
MySQL: log_error_verbosity = 3
Check docs for more info about the error
Error: 2006 (CR_SERVER_GONE_ERROR)
Message: MySQL server has gone away
Generally you can retry connecting and then doing the query again to solve this problem - try like 3-4 times before completely giving up.
I'll assuming you are using PDO. If so then you would catch the PDO Exception, increment a counter and then try again if the counter is under a threshold.
If you have a query that is causing a timeout you can set this variable by executing:
SET ##GLOBAL.wait_timeout=300;
SET ##LOCAL.wait_timeout=300; -- OR current session only
Where 300 is the number of seconds you think the maximum time the query could take.
Further information on how to deal with Mysql connection issues.
EDIT: Two other settings you may want to also use is net_write_timeout and net_read_timeout.
In MAMP (non-pro version) I added
--max_allowed_packet=268435456
to ...\MAMP\bin\startMysql.sh
Credits and more details here
If you are using xampp server :
Go to xampp -> mysql -> bin -> my.ini
Change below parameter :
max_allowed_packet = 500M
innodb_log_file_size = 128M
This helped me a lot :)
This error is occur due to expire of wait_timeout .
Just go to mysql server check its wait_timeout :
mysql> SHOW VARIABLES LIKE 'wait_timeout'
mysql> set global wait_timeout = 600 # 10 minute or maximum wait time
out you need
http://sggoyal.blogspot.in/2015/01/2006-mysql-server-has-gone-away.html
I was getting this same error on my DigitalOcean Ubuntu server.
I tried changing the max_allowed_packet and the wait_timeout settings but neither of them fixed it.
It turns out that my server was out of RAM. I added a 1GB swap file and that fixed my problem.
Check your memory with free -h to see if that's what's causing it.
On windows those guys using xampp should use this path xampp/mysql/bin/my.ini and change max_allowed_packet(under section[mysqld])to your choice size.
e.g
max_allowed_packet=8M
Again on php.ini(xampp/php/php.ini) change upload_max_filesize the choice size.
e.g
upload_max_filesize=8M
Gave me a headache for sometime till i discovered this. Hope it helps.
It was RAM problem for me.
I was having the same problem even on a server with 12 CPU cores and 32 GB RAM. I researched more and tried to free up RAM. Here is the command I used on Ubuntu 14.04 to free up RAM:
sync && echo 3 | sudo tee /proc/sys/vm/drop_caches
And, it fixed everything. I have set it under cron to run every hour.
crontab -e
0 * * * * bash /root/ram.sh;
And, you can use this command to check how much free RAM available:
free -h
And, you will get something like this:
total used free shared buffers cached
Mem: 31G 12G 18G 59M 1.9G 973M
-/+ buffers/cache: 9.9G 21G
Swap: 8.0G 368M 7.6G
In my case it was low value of open_files_limit variable, which blocked the access of mysqld to data files.
I checked it with :
mysql> SHOW VARIABLES LIKE 'open%';
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| open_files_limit | 1185 |
+------------------+-------+
1 row in set (0.00 sec)
After I changed the variable to big value, our server was alive again :
[mysqld]
open_files_limit = 100000
This generally indicates MySQL server connectivity issues or timeouts.
Can generally be solved by changing wait_timeout and max_allowed_packet in my.cnf or similar.
I would suggest these values:
wait_timeout = 28800
max_allowed_packet = 8M
If you are using the 64Bit WAMPSERVER, please search for multiple occurrences of max_allowed_packet because WAMP uses the value set under [wampmysqld64] and not the value set under [mysqldump], which for me was the issue, I was updating the wrong one. Set this to something like max_allowed_packet = 64M.
Hopefully this helps other Wampserver-users out there.
There is an easier way if you are using XAMPP.
Open the XAMPP control panel, and click on the config button in mysql section.
Now click on the my.ini and it will open in the editor. Update the max_allowed_packet to your required size.
Then restart the mysql service. Click on stop on the Mysql service click start again. Wait for a few minutes.
Then try to run your Mysql query again. Hope it will work.
It's always a good idea to check the logs of the Mysql server, for the reason why it went away.
It will tell you.
MAMP 5.3, you will not find my.cnf and adding them does not work as that max_allowed_packet is stored in variables.
One solution can be:
Go to http://localhost/phpmyadmin
Go to SQL tab
Run SHOW VARIABLES and check the values, if it is small then run with big values
Run the following query, it set max_allowed_packet to 7gb:
set global max_allowed_packet=268435456;
For some, you may need to increase the following values as well:
set global wait_timeout = 600;
set innodb_log_file_size =268435456;
For Vagrant Box, make sure you allocate enough memory to the box
config.vm.provider "virtualbox" do |vb|
vb.memory = "4096"
end
This might be a problem of your .sql file size.
If you are using xampp. Go to the xampp control panel -> Click MySql config -> Open my.ini.
Increase the packet size.
max_allowed_packet = 2M -> 10M
The unlikely scenario is you have a firewall between the client and the server that forces TCP reset into the connection.
I had that issue, and I found our corporate F5 firewall was configured to terminate inactive sessions that are idle for more than 5 mins.
Once again, this is the unlikely scenario.
uncomment the ligne below in your my.ini/my.cnf, this will split your large file into smaller portion
# binary logging format - mixed recommended
# binlog_format=mixed
TO
# binary logging format - mixed recommended
binlog_format=mixed
I found the solution to "#2006 - MySQL server has gone away" this error.
Solution is just you have to check two files
config.inc.php
config.sample.inc.php
Path of these files in windows is
C:\wamp64\apps\phpmyadmin4.6.4
In these two files the value of this:
$cfg['Servers'][$i]['host']must be 'localhost' .
In my case it was:
$cfg['Servers'][$i]['host'] = '127.0.0.1';
change it to:
"$cfg['Servers'][$i]['host']" = 'localhost';
Make sure in both:
config.inc.php
config.sample.inc.php files it must be 'localhost'.
And last set:
$cfg['Servers'][$i]['AllowNoPassword'] = true;
Then restart Wampserver.
To change phpmyadmin user name and password
You can directly change the user name and password of phpmyadmin through config.inc.php file
These two lines
$cfg['Servers'][$i]['user'] = 'root';
$cfg['Servers'][$i]['password'] = '';
Here you can give new user name and password.
After changes save the file and restart WAMP server.
I got Error 2006 message in different MySQL clients software on my Ubuntu desktop. It turned out that my JDBC driver version was too old.
I had the same problem in docker adding below setting in docker-compose.yml:
db:
image: mysql:8.0
command: --wait_timeout=800 --max_allowed_packet=256M --character-set-server=utf8 --collation-server=utf8_general_ci --default-authentication-plugin=mysql_native_password
volumes:
- ./docker/mysql/data:/var/lib/mysql
- ./docker/mysql/dump:/docker-entrypoint-initdb.d
ports:
- 3306:3306
environment:
MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
MYSQL_DATABASE: ${MYSQL_DATABASE}
MYSQL_USER: ${MYSQL_USER}
MYSQL_PASSWORD: ${MYSQL_PASSWORD}
I also encountered this error. But even with the increased max_allowed_packet or any increase of value in the my.cnf, the error still persists.
What I did is I troubleshoot my database:
I checked the tables where the error persists
Then I checked each row
There are rows that are okay to fetch and there are rows where the error only shows up
It seems that there are value in these rows that is causing this error
But even by selecting only the primary column, the error still shows up (SELECT primary_id FROM table)
The solution that I thought of is to reimport the database. Good thing is I have a backup of this database. But I only dropped the problematic table, then import my backup of this table. That solved my problem.
My takeaway of this problem:
Always have a backup of your database. Either manually or thru CRON job
I noticed that there are special characters in the affected rows. So when I recovered the table, I immediately changed the collation of this table from latin1_swedish_ci to utf8_general_ci
My database was working fine before then my system suddenly encountered this problem. Maybe it also has something to do with the upgrade of the MySQL database by our hosting provider. So frequent backup is a must!
Just in case this helps anyone:
I got this error when I opened and closed connections in a function which would be called from several parts of the application.
We got too many connections so we thought it might be a good idea to reuse the existing connection or throw it away and make a new one like so:
public static function getConnection($database, $host, $user, $password){
if (!self::$instance) {
return self::newConnection($database, $host, $user, $password);
} elseif ($database . $host . $user != self::$connectionDetails) {
self::$instance->query('KILL CONNECTION_ID()');
self::$instance = null;
return self::newConnection($database, $host, $user, $password);
}
return self::$instance;
}
Well turns out we've been a little too thorough with the killing and so the processes doing important things on the old connection could never finish their business.
So we dropped these lines
self::$instance->query('KILL CONNECTION_ID()');
self::$instance = null;
and as the hardware and setup of the machine allows it we increased the number of allowed connections on the server by adding
max_connections = 500
to our configuration file. This fixed our problem for now and we learned something about killing mysql connections.
For users using XAMPP, there are 2 max_allowed_packet parameters in C:\xampp\mysql\bin\my.ini.
This error happens basically for two reasons.
You have a too low RAM.
The database connection is closed when you try to connect.
You can try this code below.
# Simplification to execute an SQL string of getting a data from the database
def get(self, sql_string, sql_vars=(), debug_sql=0):
try:
self.cursor.execute(sql_string, sql_vars)
return self.cursor.fetchall()
except (AttributeError, MySQLdb.OperationalError):
self.__init__()
self.cursor.execute(sql_string, sql_vars)
return self.cursor.fetchall()
It mitigates the error whatever the reason behind it, especially for the second reason.
If it's caused by low RAM, you either have to raise database connection efficiency from the code, from the database configuration, or simply raise the RAM.
For me it helped to fix one's innodb table's corrupted index tree. I localized such a table by this command
mysqlcheck -uroot --databases databaseName
result
mysqlcheck: Got error: 2013: Lost connection to MySQL server during query when executing 'CHECK TABLE ...
as followed I was able to see only from the mysqld logs /var/log/mysqld.log which table was causing troubles.
FIL_PAGE_PREV links 2021-08-25T14:05:22.182328Z 2 [ERROR] InnoDB: Corruption of an index tree: table `database`.`tableName` index `PRIMARY`, father ptr page no 1592, child page no 1234'
The mysqlcheck command did not fix it, but helped to unveil it.
Ultimately I fixed it as followed by a regular mysql command from a mysql cli
OPTIMIZE table theCorruptedTableNameMentionedAboveInTheMysqld.log
I get this error when I try to source a large SQL file (a big INSERT query).
mysql> source file.sql
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 2
Current database: *** NONE ***
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 3
Current database: *** NONE ***
Nothing in the table is updated. I've tried deleting and undeleting the table/database, as well as restarting MySQL. None of these things resolve the problem.
Here is my max-packet size:
+--------------------+---------+
| Variable_name | Value |
+--------------------+---------+
| max_allowed_packet | 1048576 |
+--------------------+---------+
Here is the file size:
$ ls -s file.sql
79512 file.sql
When I try the other method...
$ ./mysql -u root -p my_db < file.sql
Enter password:
ERROR 2006 (HY000) at line 1: MySQL server has gone away
max_allowed_packet=64M
Adding this line into my.cnf file solves my problem.
This is useful when the columns have large values, which cause the issues, you can find the explanation here.
On Windows this file is located at: "C:\ProgramData\MySQL\MySQL Server
5.6"
On Linux (Ubuntu): /etc/mysql
You can increase Max Allowed Packet
SET GLOBAL max_allowed_packet=1073741824;
http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html#sysvar_max_allowed_packet
The global update and the my.cnf settings didn't work for me for some reason. Passing the max_allowed_packet value directly to the client worked here:
mysql -h <hostname> -u username -p --max_allowed_packet=1073741824 <databasename> < db.sql
In general the error:
Error: 2006 (CR_SERVER_GONE_ERROR) - MySQL server has gone away
means that the client couldn't send a question to the server.
mysql import
In your specific case while importing the database file via mysql, this most likely mean that some of the queries in the SQL file are too large to import and they couldn't be executed on the server, therefore client fails on the first occurred error.
So you've the following possibilities:
Add force option (-f) for mysql to proceed and execute rest of the queries.
This is useful if the database has some large queries related to cache which aren't relevant anyway.
Increase max_allowed_packet and wait_timeout in your server config (e.g. ~/.my.cnf).
Dump the database using --skip-extended-insert option to break down the large queries. Then import it again.
Try applying --max-allowed-packet option for mysql.
Common reasons
In general this error could mean several things, such as:
a query to the server is incorrect or too large,
Solution: Increase max_allowed_packet variable.
Make sure the variable is under [mysqld] section, not [mysql].
Don't afraid to use large numbers for testing (like 1G).
Don't forget to restart the MySQL/MariaDB server.
Double check the value was set properly by:
mysql -sve "SELECT ##max_allowed_packet" # or:
mysql -sve "SHOW VARIABLES LIKE 'max_allowed_packet'"
You got a timeout from the TCP/IP connection on the client side.
Solution: Increase wait_timeout variable.
You tried to run a query after the connection to the server has been closed.
Solution: A logic error in the application should be corrected.
Host name lookups failed (e.g. DNS server issue), or server has been started with --skip-networking option.
Another possibility is that your firewall blocks the MySQL port (e.g. 3306 by default).
The running thread has been killed, so retry again.
You have encountered a bug where the server died while executing the query.
A client running on a different host does not have the necessary privileges to connect.
And many more, so learn more at: B.5.2.9 MySQL server has gone away.
Debugging
Here are few expert-level debug ideas:
Check the logs, e.g.
sudo tail -f $(mysql -Nse "SELECT ##GLOBAL.log_error")
Test your connection via mysql, telnet or ping functions (e.g. mysql_ping in PHP).
Use tcpdump to sniff the MySQL communication (won't work for socket connection), e.g.:
sudo tcpdump -i lo0 -s 1500 -nl -w- port mysql | strings
On Linux, use strace. On BSD/Mac use dtrace/dtruss, e.g.
sudo dtruss -a -fn mysqld 2>&1
See: Getting started with DTracing MySQL
Learn more how to debug MySQL server or client at: 26.5 Debugging and Porting MySQL.
For reference, check the source code in sql-common/client.c file responsible for throwing the CR_SERVER_GONE_ERROR error for the client command.
MYSQL_TRACE(SEND_COMMAND, mysql, (command, header_length, arg_length, header, arg));
if (net_write_command(net,(uchar) command, header, header_length,
arg, arg_length))
{
set_mysql_error(mysql, CR_SERVER_GONE_ERROR, unknown_sqlstate);
goto end;
}
I solved the error ERROR 2006 (HY000) at line 97: MySQL server has gone away and successfully migrated a >5GB sql file by performing these two steps in order:
Created /etc/my.cnf as others have recommended, with the following contents:
[mysql]
connect_timeout = 43200
max_allowed_packet = 2048M
net_buffer_length = 512M
debug-info = TRUE
Appending the flags --force --wait --reconnect to the command (i.e. mysql -u root -p -h localhost my_db < file.sql --verbose --force --wait --reconnect).
Important Note: It was necessary to perform both steps, because if I didn't bother making the changes to /etc/my.cnf file as well as appending those flags, some of the tables were missing after the import.
System used: OSX El Capitan 10.11.5; mysql Ver 14.14 Distrib 5.5.51 for osx10.8 (i386)
Just in case, to check variables you can use
$> mysqladmin variables -u user -p
This will display the current variables, in this case max_allowed_packet, and as someone said in another answer you can set it temporarily with
mysql> SET GLOBAL max_allowed_packet=1072731894
In my case the cnf file was not taken into account and I don't know why, so the SET GLOBAL code really helped.
You can also log into the database as root (or SUPER privilege) and do
set global max_allowed_packet=64*1024*1024;
doesn't require a MySQL restart as well. Note that you should fix your my.cnf file as outlined in other solutions:
[mysqld]
max_allowed_packet=64M
And confirm the change after you've restarted MySQL:
show variables like 'max_allowed_packet';
You can use the command-line as well, but that may require updating the start/stop scripts which may not survive system updates and patches.
As requested, I'm adding my own answer here. Glad to see it works!
The solution is increasing the values given the wait_timeout and the connect_timeout parameters in your options file, under the [mysqld] tag.
I had to recover a 400MB mysql backup and this worked for me (the values I've used below are a bit exaggerated, but you get the point):
[mysqld]
port=3306
explicit_defaults_for_timestamp = TRUE
connect_timeout = 1000000
net_write_timeout = 1000000
wait_timeout = 1000000
max_allowed_packet = 1024M
interactive_timeout = 1000000
net_buffer_length = 200M
net_read_timeout = 1000000
set GLOBAL delayed_insert_timeout=100000
Blockquote
I had the same problem but changeing max_allowed_packet in the my.ini/my.cnf file under [mysqld] made the trick.
add a line
max_allowed_packet=500M
now restart the MySQL service once you are done.
A couple things could be happening here;
Your INSERT is running long, and client is disconnecting. When it reconnects it's not selecting a database, hence the error. One option here is to run your batch file from the command line, and select the database in the arguments, like so;
$ mysql db_name < source.sql
Another is to run your command via php or some other language. After each long - running statement, you can close and re-open the connection, ensuring that you're connected at the start of each query.
If you are on Mac and installed mysql through brew like me, the following worked.
cp $(brew --prefix mysql)/support-files/my-default.cnf /usr/local/etc/my.cnf
Source: For homebrew mysql installs, where's my.cnf?
add max_allowed_packet=1073741824 to /usr/local/etc/my.cnf
mysql.server restart
I had the same problem in XAMMP
Metode-01: I changed max_allowed_packet in the D:\xampp\mysql\bin\my.ini file like that below:
max_allowed_packet=500M
Finally restart the MySQL service once and done.
Metode-02:
the easier way if you are using XAMPP. Open the XAMPP control panel, and click on the config button in mysql section.
Now click on the my.ini and it will open in the editor. Update the max_allowed_packet to your required size.
Then restart the mysql service. Click on stop on the Mysql service click start again. Wait for a few minutes.
Then try to run your Mysql query again. Hope it will work.
I encountered this error when I use Mysql Cluster, I do not know this question is from a cluster usage or not. As the error is exactly the same, so give my solution here.
Getting this error because the data nodes suddenly crash. But when the nodes crash, you can still get the correct result using cmd:
ndb_mgm -e 'ALL REPORT MEMORYUSAGE'
And the mysqld also works correctly.So at first, I can not understand what is wrong. And about 5 mins later, ndb_mgm result shows no data node working. Then I realize the problem. So, try to restart all the data nodes, then the mysql server is back and everything is OK.
But one thing is weird to me, after I lost mysql server for some queries, when I use cmd like show tables, I can still get the return info like 33 rows in set (5.57 sec), but no table info is displayed.
This error message also occurs when you created the SCHEMA with a different COLLATION than the one which is used in the dump. So, if the dump contains
CREATE TABLE `mytab` (
..
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
you should also reflect this in the SCHEMA collation:
CREATE SCHEMA myschema COLLATE utf8_unicode_ci;
I had been using utf8mb4_general_ci in the schema, cause my script came from a fresh V8 installation, now loading a DB on old 5.7 crashed and drove me nearly crazy.
So, maybe this helps you saving some frustating hours... :-)
(MacOS 10.3, mysql 5.7)
Add max_allowed_packet=64M to [mysqld]
[mysqld]
max_allowed_packet=64M
Restart the MySQL server.
If it's reconnecting and getting connection ID 2, the server has almost definitely just crashed.
Contact the server admin and get them to diagnose the problem. No non-malicious SQL should crash the server, and the output of mysqldump certainly should not.
It is probably the case that the server admin has made some big operational error such as assigning buffer sizes of greater than the architecture's address-space limits, or more than virtual memory capacity. The MySQL error-log will probably have some relevant information; they will be monitoring this if they are competent anyway.
This is more of a rare issue but I have seen this if someone has copied the entire /var/lib/mysql directory as a way of migrating their DB to another server. The reason it doesn't work is because the database was running and using log files. It doesn't work sometimes if there are logs in /var/log/mysql. The solution is to copy the /var/log/mysql files as well.
For amazon RDS (it's my case), you can change the max_allowed_packet parameter value to any numeric value in bytes that makes sense for the biggest data in any insert you may have (e.g.: if you have some 50mb blob values in your insert, set the max_allowed_packet to 64M = 67108864), in a new or existing parameter-group. Then apply that parameter-group to your MySQL instance (may require rebooting the instance).
For Drupal 8 users looking for solution for DB import failure:
At end of sql dump file there can commands inserting data to "webprofiler" table.
That's I guess some debug log file and is not really important for site to work so all this can be removed. I deleted all those inserts including LOCK TABLES and UNLOCK TABLES (and everything between). It's at very bottom of the sql file. Issue is described here:
https://www.drupal.org/project/devel/issues/2723437
But there is no solution for it beside truncating that table.
BTW I tried all solutions from answers above and nothing else helped.
I've tried all of above solutions, all failed.
I ended up with using -h 127.0.0.1 instead of using default var/run/mysqld/mysqld.sock.
If you have tried all these solutions, esp. increasing max_allowed_packet up to the maximum supported amount of 1GB and you are still seeing these errors, it might be that your server literally does not have enough free RAM memory available...
The solution = upgrade your server to more RAM memory, and try again.
Note: I'm surprised this simple solution has not been mentioned after 8+ years of discussion on this thread... sometimes we developers tend to overthink things.
Eliminating the errors which triggered Warnings was the final solution for me. I also changed the max_allowed_packet which helped with smaller files with errors. Eliminating the errors also sped up the process incredibly.
if none of this answers solves you the problem, I solved it by removing the tables and creating them again automatically in this way:
when creating the backup, first backup structure and be sure of add:
DROP TABLE / VIEW / PROCEDURE / FUNCTION / EVENT
CREATE PROCEDURE / FUNCTION / EVENT
IF NOT EXISTS
AUTO_INCREMENT
then just use this backup with your db and it will remove and recreate the tables you need.
Then you backup just data, and do the same, and it will work.
How about using the mysql client like this:
mysql -h <hostname> -u username -p <databasename> < file.sql
I tried to import a large sql file through phpMyAdmin...But it kept showing error
'MySql server has gone away'
What to do?
As stated here:
Two most common reasons (and fixes) for the MySQL server has gone away
(error 2006) are:
Server timed out and closed the connection. How to fix:
check that wait_timeout variable in your mysqld’s my.cnf configuration file is large enough. On Debian: sudo nano
/etc/mysql/my.cnf, set wait_timeout = 600 seconds (you can
tweak/decrease this value when error 2006 is gone), then sudo
/etc/init.d/mysql restart. I didn't check, but the default value for
wait_timeout might be around 28800 seconds (8 hours).
Server dropped an incorrect or too large packet. If mysqld gets a packet that is too large or incorrect, it assumes that something has
gone wrong with the client and closes the connection. You can increase
the maximal packet size limit by increasing the value of
max_allowed_packet in my.cnf file. On Debian: sudo nano
/etc/mysql/my.cnf, set max_allowed_packet = 64M (you can
tweak/decrease this value when error 2006 is gone), then sudo
/etc/init.d/mysql restart.
Edit:
Notice that MySQL option files do not have their commands already available as comments (like in php.ini for instance). So you must type any change/tweak in my.cnf or my.ini and place them in mysql/data directory or in any of the other paths, under the proper group of options such as [client], [myslqd], etc. For example:
[mysqld]
wait_timeout = 600
max_allowed_packet = 64M
Then restart the server. To get their values, type in the mysql client:
> select ##wait_timeout;
> select ##max_allowed_packet;
For me this solution didn't work out so I executed
SET GLOBAL max_allowed_packet=1073741824;
in my SQL client.
If not able to change this with MYSql service running, you should stop the service and change the variable in "my.ini" file.
For example:
max_allowed_packet=20M
If you are working on XAMPP then you can fix the MySQL Server has gone away issue with following changes..
open your my.ini file
my.ini location is (D:\xampp\mysql\bin\my.ini)
change the following variable values
max_allowed_packet = 64M
innodb_lock_wait_timeout = 500
If you are running with default values then you have a lot of room to optimize your mysql configuration.
The first step I recommend is to increase the max_allowed_packet to 128M.
Then download the MySQL Tuning Primer script and run it. It will provide recommendations to several facets of your config for better performance.
Also look into adjusting your timeout values both in MySQL and PHP.
How big (file size) is the file you are importing and are you able to import the file using the mysql command line client instead of PHPMyAdmin?
If you are using MAMP on OS X, you will need to change the max_allowed_packet value in the template for MySQL.
You can find it at: File > Edit template > MySQL my.cnf
Then just search for max_allowed_packet, change the value and
save.
I had this error and other related ones, when I imported at 16 GB SQL file. For me, editing my.ini and setting the following (based on several different posts) in the [mysqld] section:
max_allowed_packet = 110M
innodb_buffer_pool_size=511M
innodb_log_file_size=500M
innodb_log_buffer_size = 800M
net_read_timeout = 600
net_write_timeout = 600
If you are running under Windows, go to the control panel, services, and look at the details for MySQL and you will see where my.ini is. Then after you edit and save my.ini, restart the mysql service (or restart the computer).
If you are using HeidiSQL, you can also set some or all of these using that.
I solved my issue with this short /etc/mysql/my.cnf file :
[mysqld]
wait_timeout = 600
max_allowed_packet = 100M
The other reason this can happen is running out of memory. Check /var/log/messages and make sure that your my.cnf is not set up to cause mysqld to allocate more memory than your machine has.
Your mysqld process can actually be killed by the kernel and then re-started by the "safe_mysqld" process without you realizing it.
Use top and watch the memory allocation while it's running to see what your headroom is.
make a backup of my.cnf before changing it.
I got same issue with
$image_base64 = base64_encode(file_get_contents($_FILES['file']['tmp_name']) );
$image = 'data:image/jpeg;base64,'.$image_base64;
$query = "insert into images(image) values('".$image."')";
mysqli_query($con,$query);
In \xampp\mysql\bin\my.ini file of phpmyadmin we get only
[mysqldump]
max_allowed_packet=110M
which is just for mysqldump -u root -p dbname . I resolved my issue by replacing above code with
max_allowed_packet=110M
[mysqldump]
max_allowed_packet=110M
I updated "max_allowed_packet" to 1024M, but it still wasn't working. It turns out my deployment script was running:
mysql --max_allowed_packet=512M --database=mydb -u root < .\db\db.sql
Be sure to explicitly specify a bigger number from the command line if you are donig it this way.
If your data includes BLOB data:
Note that an import of data from the command line seems to choke on BLOB data, resulting in the 'MySQL server has gone away' error.
To avoid this, re-create the mysqldump but with the --hex-blob flag:
http://dev.mysql.com/doc/refman/5.7/en/mysqldump.html#option_mysqldump_hex-blob
which will write out the data file with hex values rather than binary amongst other text.
PhpMyAdmin also has the option "Dump binary columns in hexadecimal notation (for example, "abc" becomes 0x616263)" which works nicely.
Note that there is a long-standing bug (as of December 2015) which means that GEOM columns are not converted:
Back up a table with a GEOMETRY column using mysqldump?
so using a program like PhpMyAdmin seems to be the only workaround (the option noted above does correctly convert GEOM columns).
If it takes a long time to fail, then enlarge the wait_timeout variable.
If it fails right away, enlarge the max_allowed_packet variable; it it still doesn't work, make sure the command is valid SQL. Mine had unescaped quotes which screwed everything up.
Also, if feasible, consider limiting the number of inserts of a single SQL command to, say, 1000. You can create a script that creates multiple statements out of a single one by reintroducing the INSERT... part every n inserts.
i got a similar error.. to solve this just open my.ini file..here at line no 36 change the value of maximum allowed packet size ie. max_allowed_packet = 20M
Make sure mysqld process does not restart because of service managers like systemd.
I had this problem in vagrant with centos 7. Configuration tweaks didn't help. Turned out it was systemd which killed mysqld service every time when it took too much memory.
I had similar error today when duplicating database (MySQL server has gone away...), but when I tried to restart mysql.server restart I got error
ERROR! The server quit without updating PID ...
This is how I solved it:
I opened up Applications/Utilities/ and ran Activity Monitor
quit mysqld
then was able to solve the error problem with
mysql.server restart
I am doing some large calculations which involves the mysql connection to stay long time and with heavy data. i was facing this "Mysql go away issue". So i tried t optimize the queries but that doen't helped me then i increased the mysql variables limit which is set to a lower value by default.
wait_timeout
max_allowed_packet
To the limit what ever suits to you it should be the Any Number * 1024(Bytes). you can login to terminal using 'mysql -u username - p' command and can check and change for these variable limits.
For GoDaddy shared hosting
On GoDaddy shared hosting accounts, it is tricky to tweak the PHP.ini etc files. However, there is another way and it just worked perfectly for me. (I just successfully uploaded a 3.8Mb .sql text file, containing 3100 rows and 145 cols. Using the IMPORT command in phpMyAdmin, I was getting the dreaded MySQL server has gone away error, and no further information.)
I found that Matt Butcher had the right answer. Like Matt, I had tried all kinds of tricks, from exporting MySQL databases in bite-sized chunks, to writing scripts that break large imports into smaller ones. But here is what worked:
(1) CPANEL ---> FILES (group) ---> BACKUP
(2a) Under "Partial Backups" heading...
(2b) Under "Download a MySQL Database Backup"
(2c) Choose your database and download a backup (this step optional, but wise)
(3a) Directly to the right of 2b, under heading "Restore a MySQL Database Backup"
(3b) Choose the .SQL import file from your local drive
(3c) True happiness will be yours (shortly....) Mine took about 5 seconds
I was able to use this method to import a single table. Nothing else in my database was affected -- but that is what step (2) above is intended to protect against.
Notes:
a. If you are unsure how to create a .SQL import file, use phpMyAdmin to export a table and modify that file structure.
SOURCE:
Matt Butcher 2010 Article
If increasing max_allowed_packet doesn't help.
I was getting the same error as you when importing a .sql file into my database via Sequel Pro.
The error still persisted after upping the max_allowed_packet to 512M so I ran the import in the command line instead with:
mysql --verbose -u root -p DatabaseName < MySQL.sql
It gave the following error:
ASCII '\0' appeared in the statement, but this is not allowed unless option --binary-mode is enabled
I found a couple helpful StackOverflow questions:
Enable binary mode while restoring a Database from an SQL dump
Mysql ERROR: ASCII '\0' while importing sql file on linux server
In my case, my .sql file was a little corrupt or something. The MySQL dump we get comes in two zip files that need to be concatenated together and then unzipped. I think the unzipping was interrupted initially, leaving the file with some odd characters and encodings. Getting a fresh MySQL dump and unzipping it properly worked for me.
Just wanted to add this here in case others find that increasing the max_allowed_packet variable was not helping.
None of the solutions regarding packet size or timeouts made any difference for me. I needed to disable ssl
mysql -u -p -hmyhost.com --disable-ssl db < file.sql
https://dev.mysql.com/doc/refman/5.7/en/encrypted-connections.html
I tried to import a large sql file through phpMyAdmin...But it kept showing error
'MySql server has gone away'
What to do?
As stated here:
Two most common reasons (and fixes) for the MySQL server has gone away
(error 2006) are:
Server timed out and closed the connection. How to fix:
check that wait_timeout variable in your mysqld’s my.cnf configuration file is large enough. On Debian: sudo nano
/etc/mysql/my.cnf, set wait_timeout = 600 seconds (you can
tweak/decrease this value when error 2006 is gone), then sudo
/etc/init.d/mysql restart. I didn't check, but the default value for
wait_timeout might be around 28800 seconds (8 hours).
Server dropped an incorrect or too large packet. If mysqld gets a packet that is too large or incorrect, it assumes that something has
gone wrong with the client and closes the connection. You can increase
the maximal packet size limit by increasing the value of
max_allowed_packet in my.cnf file. On Debian: sudo nano
/etc/mysql/my.cnf, set max_allowed_packet = 64M (you can
tweak/decrease this value when error 2006 is gone), then sudo
/etc/init.d/mysql restart.
Edit:
Notice that MySQL option files do not have their commands already available as comments (like in php.ini for instance). So you must type any change/tweak in my.cnf or my.ini and place them in mysql/data directory or in any of the other paths, under the proper group of options such as [client], [myslqd], etc. For example:
[mysqld]
wait_timeout = 600
max_allowed_packet = 64M
Then restart the server. To get their values, type in the mysql client:
> select ##wait_timeout;
> select ##max_allowed_packet;
For me this solution didn't work out so I executed
SET GLOBAL max_allowed_packet=1073741824;
in my SQL client.
If not able to change this with MYSql service running, you should stop the service and change the variable in "my.ini" file.
For example:
max_allowed_packet=20M
If you are working on XAMPP then you can fix the MySQL Server has gone away issue with following changes..
open your my.ini file
my.ini location is (D:\xampp\mysql\bin\my.ini)
change the following variable values
max_allowed_packet = 64M
innodb_lock_wait_timeout = 500
If you are running with default values then you have a lot of room to optimize your mysql configuration.
The first step I recommend is to increase the max_allowed_packet to 128M.
Then download the MySQL Tuning Primer script and run it. It will provide recommendations to several facets of your config for better performance.
Also look into adjusting your timeout values both in MySQL and PHP.
How big (file size) is the file you are importing and are you able to import the file using the mysql command line client instead of PHPMyAdmin?
If you are using MAMP on OS X, you will need to change the max_allowed_packet value in the template for MySQL.
You can find it at: File > Edit template > MySQL my.cnf
Then just search for max_allowed_packet, change the value and
save.
I had this error and other related ones, when I imported at 16 GB SQL file. For me, editing my.ini and setting the following (based on several different posts) in the [mysqld] section:
max_allowed_packet = 110M
innodb_buffer_pool_size=511M
innodb_log_file_size=500M
innodb_log_buffer_size = 800M
net_read_timeout = 600
net_write_timeout = 600
If you are running under Windows, go to the control panel, services, and look at the details for MySQL and you will see where my.ini is. Then after you edit and save my.ini, restart the mysql service (or restart the computer).
If you are using HeidiSQL, you can also set some or all of these using that.
I solved my issue with this short /etc/mysql/my.cnf file :
[mysqld]
wait_timeout = 600
max_allowed_packet = 100M
The other reason this can happen is running out of memory. Check /var/log/messages and make sure that your my.cnf is not set up to cause mysqld to allocate more memory than your machine has.
Your mysqld process can actually be killed by the kernel and then re-started by the "safe_mysqld" process without you realizing it.
Use top and watch the memory allocation while it's running to see what your headroom is.
make a backup of my.cnf before changing it.
I got same issue with
$image_base64 = base64_encode(file_get_contents($_FILES['file']['tmp_name']) );
$image = 'data:image/jpeg;base64,'.$image_base64;
$query = "insert into images(image) values('".$image."')";
mysqli_query($con,$query);
In \xampp\mysql\bin\my.ini file of phpmyadmin we get only
[mysqldump]
max_allowed_packet=110M
which is just for mysqldump -u root -p dbname . I resolved my issue by replacing above code with
max_allowed_packet=110M
[mysqldump]
max_allowed_packet=110M
I updated "max_allowed_packet" to 1024M, but it still wasn't working. It turns out my deployment script was running:
mysql --max_allowed_packet=512M --database=mydb -u root < .\db\db.sql
Be sure to explicitly specify a bigger number from the command line if you are donig it this way.
If your data includes BLOB data:
Note that an import of data from the command line seems to choke on BLOB data, resulting in the 'MySQL server has gone away' error.
To avoid this, re-create the mysqldump but with the --hex-blob flag:
http://dev.mysql.com/doc/refman/5.7/en/mysqldump.html#option_mysqldump_hex-blob
which will write out the data file with hex values rather than binary amongst other text.
PhpMyAdmin also has the option "Dump binary columns in hexadecimal notation (for example, "abc" becomes 0x616263)" which works nicely.
Note that there is a long-standing bug (as of December 2015) which means that GEOM columns are not converted:
Back up a table with a GEOMETRY column using mysqldump?
so using a program like PhpMyAdmin seems to be the only workaround (the option noted above does correctly convert GEOM columns).
If it takes a long time to fail, then enlarge the wait_timeout variable.
If it fails right away, enlarge the max_allowed_packet variable; it it still doesn't work, make sure the command is valid SQL. Mine had unescaped quotes which screwed everything up.
Also, if feasible, consider limiting the number of inserts of a single SQL command to, say, 1000. You can create a script that creates multiple statements out of a single one by reintroducing the INSERT... part every n inserts.
i got a similar error.. to solve this just open my.ini file..here at line no 36 change the value of maximum allowed packet size ie. max_allowed_packet = 20M
Make sure mysqld process does not restart because of service managers like systemd.
I had this problem in vagrant with centos 7. Configuration tweaks didn't help. Turned out it was systemd which killed mysqld service every time when it took too much memory.
I had similar error today when duplicating database (MySQL server has gone away...), but when I tried to restart mysql.server restart I got error
ERROR! The server quit without updating PID ...
This is how I solved it:
I opened up Applications/Utilities/ and ran Activity Monitor
quit mysqld
then was able to solve the error problem with
mysql.server restart
I am doing some large calculations which involves the mysql connection to stay long time and with heavy data. i was facing this "Mysql go away issue". So i tried t optimize the queries but that doen't helped me then i increased the mysql variables limit which is set to a lower value by default.
wait_timeout
max_allowed_packet
To the limit what ever suits to you it should be the Any Number * 1024(Bytes). you can login to terminal using 'mysql -u username - p' command and can check and change for these variable limits.
For GoDaddy shared hosting
On GoDaddy shared hosting accounts, it is tricky to tweak the PHP.ini etc files. However, there is another way and it just worked perfectly for me. (I just successfully uploaded a 3.8Mb .sql text file, containing 3100 rows and 145 cols. Using the IMPORT command in phpMyAdmin, I was getting the dreaded MySQL server has gone away error, and no further information.)
I found that Matt Butcher had the right answer. Like Matt, I had tried all kinds of tricks, from exporting MySQL databases in bite-sized chunks, to writing scripts that break large imports into smaller ones. But here is what worked:
(1) CPANEL ---> FILES (group) ---> BACKUP
(2a) Under "Partial Backups" heading...
(2b) Under "Download a MySQL Database Backup"
(2c) Choose your database and download a backup (this step optional, but wise)
(3a) Directly to the right of 2b, under heading "Restore a MySQL Database Backup"
(3b) Choose the .SQL import file from your local drive
(3c) True happiness will be yours (shortly....) Mine took about 5 seconds
I was able to use this method to import a single table. Nothing else in my database was affected -- but that is what step (2) above is intended to protect against.
Notes:
a. If you are unsure how to create a .SQL import file, use phpMyAdmin to export a table and modify that file structure.
SOURCE:
Matt Butcher 2010 Article
If increasing max_allowed_packet doesn't help.
I was getting the same error as you when importing a .sql file into my database via Sequel Pro.
The error still persisted after upping the max_allowed_packet to 512M so I ran the import in the command line instead with:
mysql --verbose -u root -p DatabaseName < MySQL.sql
It gave the following error:
ASCII '\0' appeared in the statement, but this is not allowed unless option --binary-mode is enabled
I found a couple helpful StackOverflow questions:
Enable binary mode while restoring a Database from an SQL dump
Mysql ERROR: ASCII '\0' while importing sql file on linux server
In my case, my .sql file was a little corrupt or something. The MySQL dump we get comes in two zip files that need to be concatenated together and then unzipped. I think the unzipping was interrupted initially, leaving the file with some odd characters and encodings. Getting a fresh MySQL dump and unzipping it properly worked for me.
Just wanted to add this here in case others find that increasing the max_allowed_packet variable was not helping.
None of the solutions regarding packet size or timeouts made any difference for me. I needed to disable ssl
mysql -u -p -hmyhost.com --disable-ssl db < file.sql
https://dev.mysql.com/doc/refman/5.7/en/encrypted-connections.html
I'm trying to upload a CSV into a mysql database using phpmyadmin
When I try with a shortened version of the database, the process works ok, but when I try with the full database, I get the error:
#2006 - MySQL server has gone away
The section of my CSV that is working is:
trans_id,price_paid,date,postcode,property_type,poperty_type_2,hold,add_num,add_flat,add_road,add_area,add_city,add_borough,add_county,add_rand
{33C588EE-BB09-4F6F-BA8C-000312C72B3B},159950,23/05/2014 00:00,SL6 9LX,F,N,L,2,,THE SHAW,COOKHAM,MAIDENHEAD,WINDSOR AND MAIDENHEAD,WINDSOR AND MAIDENHEAD,A
{2C650B8C-57C0-421C-A4A9-00037BDFDCFB},158000,30/05/2014 00:00,NN14 1RJ,T,N,F,4,,MIDLAND COTTAGES,RUSHTON,KETTERING,KETTERING,NORTHAMPTONSHIRE,A
{74FA45D0-CB64-40E1-94C4-00055AEBF72C},470000,30/05/2014 00:00,KT20 5SF,D,N,F,11,,CHAPEL ROAD,,TADWORTH,REIGATE AND BANSTEAD,SURREY,A
{054AB14B-0EED-48FD-B3CD-0005B154A5C3},135000,23/05/2014 00:00,NR27 9AZ,F,N,L,48,,ALBANY COURT,,CROMER,NORTH NORFOLK,NORFOLK,A
{86896E40-68BA-4BA2-8468-0006258B9C41},124995,09/05/2014 00:00,L24 9NA,S,Y,L,131,,ADDENBROOKE DRIVE,SPEKE,LIVERPOOL,LIVERPOOL,MERSEYSIDE,A
{A948BD6F-DD91-4DE9-82D1-0008226FC360},95000,13/06/2014 00:00,HU6 7XE,S,N,F,51,,DOWNFIELD AVENUE,,HULL,CITY OF KINGSTON UPON HULL,CITY OF KINGSTON UPON HULL,A
{7191F69F-7648-4603-9CE7-000882808E16},174000,19/05/2014 00:00,DT5 1HX,T,N,F,2,,LONG ACRE,,PORTLAND,WEYMOUTH AND PORTLAND,DORSET,A
{525BE511-1351-475F-9765-0009645D0B60},328000,11/06/2014 00:00,TW18 2EP,T,N,F,1,,EDGELL ROAD,,STAINES-UPON-THAMES,SPELTHORNE,SURREY,A
I've tried:
increasing the max_packet=64M in /etc/my.cnf to 64M, and the wait_timeout= 1000 but no luck.
I've also made the same changes for the packet size limit on the php.ini but no luck.
Any help would be appreciated
Thanks,
Mo
Check out the documentation on MySQL error #2006. I've included some of the more likely possibilities below:
You have encountered a timeout on the server side and the automatic reconnection in the client is disabled (the reconnect flag in the MYSQL structure is equal to 0).
You can also get these errors if you send a query to the server that is incorrect or too large. If mysqld receives a packet that is too large or out of order, it assumes that something has gone wrong with the client and closes the connection. If you need big queries (for example, if you are working with big BLOB columns), you can increase the query limit by setting the server's max_allowed_packet variable, which has a default value of 1MB. You may also need to increase the maximum packet size on the client end. More information on setting the packet size is given in Section B.5.2.10, “Packet Too Large”. This likely isn't the issue, as you've already done the suggested solution.
You also get a lost connection if you are sending a packet 16MB or larger if your client is older than 4.0.8 and your server is 4.0.8 and above, or the other way around.
There's also an error specific for Windows applications, so if you're using Windows, check that out:
You are using a Windows client and the server had dropped the connection (probably because wait_timeout expired) before the command was issued. The problem on Windows is that in some cases MySQL does not get an error from the OS when writing to the TCP/IP connection to the server, but instead gets the error when trying to read the answer from the connection. Prior to MySQL 5.0.19, even if the reconnect flag in the MYSQL structure is equal to 1, MySQL does not automatically reconnect and re-issue the query as it doesn't know if the server did get the original query or not. The solution to this is to either do a mysql_ping() on the connection if there has been a long time since the last query (this is what Connector/ODBC does) or set wait_timeout on the mysqld server so high that it in practice never times out.