They're valuable if the server is used to implement a COMET server.
We maintain a large number of connections (doing overlapping long polling) and we send the same information to each connection (about 30 times an hour at peak). Even if the query to produce that data was poorly optimised it's only being performed once and then the results pushed out to every connection.
We maintain a large number of connections (doing overlapping long polling) and we send the same information to each connection (about 30 times an hour at peak). Even if the query to produce that data was poorly optimised it's only being performed once and then the results pushed out to every connection.