Slow performance of POS tagging. Can I do some kind of pre-warming?

Question

I am using NLTK to POS-tag hundereds of tweets in a web request. As you know, Django instantiates a request handler for each request.

I noticed this: for a request (~200 tweets), the first tweet needs ~18 seconds to tag, while all subsequent tweets need ~120 milliseconds to tag. What can I do to speed up the process?

Can I do a "pre-warming request" so that the module data is already loaded for each request?

class MyRequestHandler(BaseHandler):
    def read(self, request): #this runs for a GET request
        #...in a loop:
            tokens = nltk.word_tokenize( tweet)
            tagged = nltk.pos_tag( tokens)

Answer 1

Those first 18 seconds are the POS tagger being unpickled from disk into RAM. If you want to get around this, load the tagger yourself outside of a request function.

import nltk.data, nltk.tag
tagger = nltk.data.load(nltk.tag._POS_TAGGER)

And then replace nltk.pos_tag with tagger.tag. The tradeoff is that app startup will now take +18seconds.