From customer:
-----------------------------------------
We have just upgraded eZ to 4.4 and php to 5.3 yesterday. But the system is not stable, our pages show very often, a Fatal error due to Memory Limit:

PHP Fatal error: Allowed memory size of 1073741824 bytes exhausted (tried to allocate 523800 bytes) in
lib/ezutils/classes/ezdebug.php on line 414 or 885 for example

After some first debug, I can say the bug doesn't really come from the logging.
eZ is looping on an error 'MySQL is gone away' like this (20s generate 200Mb of logs)

)'eZDBInterface::commit TRANSID-3e498e3dd076bd61b57d13ec4f82ea48:
Transaction in progress failed due to DB error, transaction was rollbacked. Transaction ID is TRANSID-3e498e3dd076bd61b57d13ec4f82ea48.'truearray (
0 => 'var/log/',
1 => 'error.log',
)'eZMySQLiDB:
Query error (2006): MySQL server has gone away. Query: ROLLBACK'truearray (
0 => 'var/log/',
1 => 'error.log',
)'eZMySQLiDB:
Query error (2006): MySQL server has gone away. Query: ROLLBACK'truearray (
0 => 'var/log/',
1 => 'error.log',
)'eZDBInterface::commit TRANSID-23838038ada2d2dffe30ffb9595bf325:
Transaction in progress failed due to DB error, transaction was rollbacked. Transaction ID is TRANSID-23838038ada2d2dffe30ffb9595bf325.'truearray (
0 => 'var/log/',
1 => 'error.log',
)'eZDBInterface::commit TRANSID-1bb19138a2e1e5a5cd54d63c368deb44:
Transaction in progress failed due to DB error, transaction was rollbacked. Transaction ID is TRANSID-1bb19138a2e1e5a5cd54d63c368deb44.'truearray (
0 => 'var/log/',
1 => 'error.log',
)'eZMySQLiDB:
Query error (2006): MySQL server has gone away. Query: ROLLBACK'truearray (
0 => 'var/log/',
1 => 'error.log',
)'eZMySQLiDB:
Query error (2006): MySQL server has gone away. Query: ROLLBACK'truearray (
0 => 'var/log/',
1 => 'error.log',
-----------------------------------------
I have attached a patch for mysql and mysqli. Unknown if other databases are affected.

Steps to reproduce

Confirmed on git master. See attached test script for reproducing.