php - How large must be a file to prevent you use DOM or SimpleXML and use a pull parser instead? -

i going build script , handle big xml file. question when have move pull parser instead of using dom or simplexml?

when xml file loaded memory, loaded every time each user requests data it, simultaneously or single time period ?

should follow "chunk method" or avoid , use sax/xmlreader ?

thank you.

tree-based representations of xml, such dom, use 5-to-10 times source document size. becomes pain above 200mb or (or less if you're trying handle high concurrency , throughput, of course).

if want avoid repeatedly loading same document memory, application should maintain cache.