MySQL server has gone away cause analysis and solutions

1, applications (such as PHP) for a long time to execute the batch of MySQL statements. The most common is acquisition or new and old data conversion.
Solution:
Add or modify the following two variables in the my.cnf file:
wait_timeout=2880000
Interactive_timeout = 2880000
A specific description of two variables can be Google or read the Official Handbook. If you cannot modify MY.CNF, you can set up client_interactive when you connect to the database, for example:
sql = "Set interactive_timeout=24*3600";
Mysql_real_query (...)

2, execute a SQL, but the SQL statement is too large or the statement contains a BLOB or Longblob field. For example, the processing of image data
Solution:
Add or modify the following variables in the my.cnf file:
Max_allowed_packet = 10M (You can also set the size you want)
The function of the Max_allowed_packet parameter is to control the maximum length of its communication buffer.

There is also a possibility for some reason to timeout, such as the use of singleton in the process of getting a database connection, although the database is connected multiple times, but in fact, the same connection is used, and a two times in the program of the operation of the database Time exceeded wait_timeout (show Status to see this setting), there may be a problem. The simplest way is to change the wait_timeout, of course, you can also in the program occasionally mysql_ping (), so that MySQL knows it is not a person in the fight.

The "MySQL (best combination of PHP) server has gone away" error occurs when you import a backup using MySQL (the best combination of PHP), possibly because some of the INSERT statements are larger than the MySQL ( The best combination of PHP with the size of the buffer currently set.

Solutions

1. When using phpMyAdmin to back up MySQL (the best combination of PHP), select only

Data:
Full insert
Extended Insert

Expand insert do not tick

2. Use MySQL (best combination of PHP) dump backup without adding--opt

This will only generate a complete INSERT statement, and there will be no error during import.

3. Modify My.ini

Open My.ini and find the [MySQL (best combination of PHP) d] line, add the following

[The best combination of MySQL (and PHP) d]

#扩大缓冲区
max_allowed_packet=32m
After saving, restart MySQL (the best combination with PHP)