Mysql : Aborted connection .../... (Got an error reading communication packets)

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

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

• Install PHP on another server that can be a dedicated web server.

• Increase the amount of RAM on the DB Server

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:

mysql> SET GLOBAL innodb_buffer_pool_size = 1024 * 1024 * 1024 * 2;

StackExchange Database Administrators Q#144773, answer score: 2