Why Does my MySQL Server Keep Saying \"General error: 2006 MySQL server has gone away\"?

MySQL Server Has Gone Away: Delving into the 'General error: 2006' Enigma

When performing bulk inserts into a MySQL database, the dreaded "SQLSTATE[HY000]: General error: 2006 MySQL server has gone away" error can surface. This seemingly elusive issue hinders the smooth execution of database operations. To unravel its secrets, we embark on a journey to understand this cryptic error and explore potential solutions.

Unveiling the Hidden Cause: The wait_timeout

The "MySQL server has gone away" error often stems from a timeout limitation. Specifically, it originates from the MySQL variable named wait_timeout. This variable determines the time (in seconds) that MySQL will patiently await client activity before terminating the connection.

By default, wait_timeout is set to 30 seconds on shared hosts. However, when a database operation exceeds this time limit, the connection is abruptly terminated, leading to the aforementioned error.

Resolving the Issue: Adjusting wait_timeout

To resolve this issue, we need to extend the wait time to accommodate the duration of our database operation. This can be achieved by issuing the query "SET session wait_timeout=28800," which sets the wait_timeout for the current session to 28800 seconds (8 hours).

Additional Considerations: Interactive Timeout

In certain scenarios, you may also need to modify the interactive_timeout variable alongside wait_timeout. This variable controls the maximum duration for idle interactive connections. If interactive_timeout is lower than the operation's execution time, the connection will be abruptly closed, resulting in the same error.

Implementation: PHP Code

To implement this solution in PHP, utilize the following code sample:

<code class="php">$results = $db->query("SHOW VARIABLES LIKE '%timeout%'", TRUE);
echo "<pre class="brush:php;toolbar:false">";
var_dump($results);
echo "

"; $results = $db->query("SET session wait_timeout=28800", FALSE); // UPDATE - this is also needed $results = $db->query("SET session interactive_timeout=28800", FALSE); $results = $db->query("SHOW VARIABLES LIKE '%timeout%'", TRUE); echo "

";
var_dump($results);
echo "

";

Before executing your database operation, add these lines to your PHP script to adjust the timeout settings. This allows the operation to complete without encountering the "MySQL server has gone away" error.

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