Speed up side-by-side diffs

[GoogleCodeExporter]

People have complained that it's slow to click on a sbs link.  Since we 
already load all the patches when the user goes to the issue page, we 
should store them in memcache, that way the sbs link doesn't load them 
again.

We should also load the patchsets into memcache so that the other people 
visiting the issue page get quicker access.

Definitely lots of room for improvement.  I'll try to make room for this 
next month, but if anyone has time before, feel free to take this on.  It 
hits Chrome teams more cause our patches are so large :)

Original issue reported on code.google.com by john.abd...@gmail.com on 4 Mar 2009 at 10:35

[GoogleCodeExporter]

Original comment by albrecht.andi on 6 Apr 2012 at 7:41

• Added labels: Component-Server

[GoogleCodeExporter]

Now that we are using ndb, the entities should often be in memcache.  But, 
there is still a lot of time spent in computing the diff and generating HTML 
fragments.    These could be stored in memcache, as suggested, or I might try 
doing more of the work of displaying the side-by-side view on the client side.

Original comment by jrobbins@google.com on 12 Jul 2014 at 5:56

• Changed title: Speed up side-by-side diffs
• Changed state: Accepted