PHP execution limits¶

There are several PHP configuration settings that may be responsible for prematurely halting a script. This is a frequent problem in many installations, especially when handling large file uploads. In the PHP site there is also a useful guide we recommend reading: Common pitfalls.

max_execution_time:

Limits the running time of a script (in seconds), e.g.:

max_execution_limit = 30

memory_limit:

Limits the amount of memory a script may consume (in bytes [B], kilobytes [K], megabytes [M] or gigabytes [G]).

memory_limit = 128M

Please note that this memory limit is not related to the amount of system memory (RAM) available, but is an artificial limit imposed by PHP to avoid run-away scripts from consuming all system resources. This implies that adjusting the PHP configuration should be done before deciding whether adding more RAM to your system may be beneficial. This limit is especially important if you are trying to process digital objects because it is needed to allocate enough memory to process both the input and the output digital object. See the following table:

Size (MB)	Megapixels
100	13
128	18
256	35
512	70