This error message had submitted many times in this forum.
I have tried the following without success.
Context
This is a Symfony1/Doctrine1 web application.
The error appear on my computer and on a serveur (both on Ubuntu).
At the browser level (Chrome) I've got an error :
POST http://*****/administration_dev.php/utilisateur net::ERR_EMPTY_RESPONSE
Here's my computer details :
$ uname -a
Linux Bureau 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04 LTS"
$ dpkg -l |grep php
ii libapache2-mod-php 1:7.0+35ubuntu6 all server-side, HTML-embedded scripting language (Apache 2 module) (default)
ii libapache2-mod-php7.0 7.0.4-7ubuntu2.1 amd64 server-side, HTML-embedded scripting language (Apache 2 module)
ii php 1:7.0+35ubuntu6 all server-side, HTML-embedded scripting language (default)
.../...
$ dpkg -l |grep mysql-
ii mysql-client-5.7 5.7.13-0ubuntu0.16.04.2 amd64 MySQL database client binaries
ii mysql-client-core-5.7 5.7.13-0ubuntu0.16.04.2 amd64 MySQL database core client binaries
ii mysql-common 5.7.13-0ubuntu0.16.04.2 all MySQL database common files, e.g. /etc/mysql/my.cnf
ii mysql-server 5.7.13-0ubuntu0.16.04.2 all MySQL database server (metapackage depending on the latest version)
ii mysql-server-5.7 5.7.13-0ubuntu0.16.04.2 amd64 MySQL database server binaries and system database setup
ii mysql-server-core-5.7 5.7.13-0ubuntu0.16.04.2 amd64 MySQL database server binaries
The error appear when I try to create a new user during the save process.
Proposition tried
#1 MySQL Error Reading Communication Packets
$ mysql -uroot -p -e "SET GLOBAL max_allowed_packet = 1024 * 1024 * 1024;"
Enter password:
$ mysql -uroot -p -e "SHOW VARIABLES LIKE 'max_allowed_packet';"
Enter password:
+--------------------+------------+
| Variable_name | Value |
+--------------------+------------+
| max_allowed_packet | 1073741824 |
+--------------------+------------+
$ tail -f -n0 /var/log/mysql/error.log
2016-07-24T19:41:32.736817Z 23 [Note] Aborted connection 23 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:41:32.906433Z 24 [Note] Aborted connection 24 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:41:33.056226Z 25 [Note] Aborted connection 25 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:41:33.212496Z 26 [Note] Aborted connection 26 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:41:33.363754Z 27 [Note] Aborted connection 27 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:41:33.516194Z 28 [Note] Aborted connection 28 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:41:33.668201Z 29 [Note] Aborted connection 29 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
#2 MySQL: Error reading communication packets
$ cat /etc/mysql/conf.d/david.cnf
[mysqld]
sql-mode=NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
max_allowed_packet = 256M
innodb_log_buffer_size = 32M
innodb_log_file_size = 2047M
$ mysql -uroot -p -e "SET GLOBAL innodb_fast_shutdown = 0;"
$ sudo service mysql stop
$ sudo mv /var/lib/mysql/ib_logfile0 /var/lib/mysql/ib_logfile0.bak
$ sudo mv /var/lib/mysql/ib_logfile1 /var/lib/mysql/ib_logfile1.bak
$ sudo service mysql start
$ tail -f -n0 /var/log/mysql/error.log
2016-07-24T19:56:02.342912Z 7 [Note] Aborted connection 7 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:56:02.494024Z 8 [Note] Aborted connection 8 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:56:02.642960Z 9 [Note] Aborted connection 9 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:56:02.787908Z 10 [Note] Aborted connection 10 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:56:02.933718Z 11 [Note] Aborted connection 11 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:56:03.084066Z 12 [Note] Aborted connection 12 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
2016-07-24T19:56:03.235319Z 13 [Note] Aborted connection 13 to db: 'pfs2' user: 'pfs2' host: 'localhost' (Got an error reading communication packets)
I'm running out of ideas and suggestions so I'm calling for help here.
Thanks for your support, I will give you more information if you need.
David.
Best Answer
You are running MySQL 5.7 with PHP on the one server. This shows me that your server is not dedicated to MySQL. PHP and MySQL are evidently competing for RAM.
I also do not see any attempt to set the InnoDB buffer pool size. The default value for innodb_buffer_pool_size is 128M (134217728).
Please keep in mind something about max_allowed_packet. As the variable name suggests, it is the maximum size allowed for a MySQL Packet. According the MySQL Documentation, the MySQL Packet does not start out as 1G. Its initial size is based on the value of net_buffer_length. The MySQL Packet will then dynamically expand to max_allowed_packet as needed.
Your attempts to tune around the MySQL Packet will be nullified by a lack of RAM.
SUGGESTION #1
SUGGESTION #2
If you cannot afford another server, then just increase RAM and the Buffer Pool size.
SUGGESTION #3 (OPTIONAL)
Since you are using MySQL 5.7, you can expand the Buffer Pool dynamically.
Do the following to set it to 2GB: