tree 0e248a407f4cf774ced463d36a362a3ee4d433a5
parent 3d271c0c6666cf9c00c32c9bab56fcf54186c583
author Dave Borowitz <dborowitz@google.com> 1373495359 -0700
committer Dave Borowitz <dborowitz@google.com> 1380740442 -0700

Don't return futures from ChangeIndex methods

In I1b3c5ba0 ChangeIndex.replace was modified to return a future, but
ChangeIndexer.Task was not changed to call those futures before
returning.

In retrospect this was a mistake anyway. The only path by which these
methods are currently called is from ChangeIndexerImpl, which turns
around and wraps them in a Callable and submits them to the same
executor, tying up twice as many threads as necessary.

Similarly, to avoid additional fanout in ChangeIndexerImpl, we should
not write to multiple index versions in parallel, so remove the TODO
to try that. The current behavior slows down individual writes for the
relatively short period of an online version upgrade, but that is
acceptable given the improved thread utilization overall.

Change-Id: I5fff470214ecd69a261dec1c10b9f7bdd0a1907e