This commit leverages the ahocorasick algorithm to build a set of user_ids
that have their alert_words present in the message. It runs in linear time
of the order of length of the input message as opposed to number of
alert_words. This is after building a ahocorasick Automaton which runs
in O(number of alert_words in entire realm) which is usually cached.
This removes from our cache a moderate amount of totally useless alert
word data corresponding to users who don't have any alert words.
Thanks to @dbiollo for the suggestion!
We want to avoid opening a DB connection in the markdown thread
as its DB connection might live for a long time
(imported from commit 7700b2ca793ee5e9add7f071b92f22a4bf576b3d)
We found that since bugdown processes are threaded, the cost of
doing a db query in a markdown processor is quite high---each
thread must start up a new db connection including a SSL handshake
etc. We should strive to keep our rendering pipeline free of mandatory
DB queries.
(imported from commit 555066bd03da6c681b74ce6137acc264eb41c55d)
Bennet Sunder
Aditya Bansal
rht
Robert Hönig
Eklavya Sharma
Tim Abbott
Ashish
Tim Abbott
Luke Faraone
Leo Franchi