During an ODBC request , many lines (2000 to 10000) are retreived
if i make a simple echo "-", the end of program is finish with 1 or 2 seconds and no memory problem is seen .
If the result is stored with a persistant object in a MySQL table (a sort of self-made PDO
), the program is running during many minutes and memory of Apache process is growing and growing , 700Mo is the score today 
In the function that make the insert, the object is new and before the function end, i write a __destruct ... but is'n better ...
