I used ini_set('memory_limit', '-1') in my code php. I googled it and I searched more, I found that I should change the "-1" to increase the size of the memory, but I work directly on the server of production, I change my file then I deploy it.
It have an effect when I upload or download the files ? It can a cause of the loss of my information when I do the dowload from Highchart ?
I think you have set in only on your your script page via php, so it will affect only your script. if you have altered php.ini server file then it will affect entire server memory limit.