runtimequestion 372 Threading & Multiprocessing · easy
Fix the lock that protects nothing
A page-view counter is updated from many web-server threads and still loses views under load, although record uses with and a lock. Find why the lock protects nothing and fix it.
Read and diagnose: this can't run in the browser, so you'll read real code and output and answer questions about it.
Class
PageViews(lock_factory=threading.Lock) with counts (a dictionary) and record(page)record(page)adds 1 to
counts[page] (missing pages start at 0) while holding the counter's lockRulethe counter creates one lock (with
lock_factory()) and every update uses it