RebuildNotedb: batch changes by project
If we batch changes by project before rebuilding them and writing them
to the notedb, we can use a single BatchRefUpdate for all of the
changes in a project, which reduces overhead for writing every change
to the notedb.
Additionally, within the code the rebuilds each change, I synchronized
on the BatchRefUpdate object because it is not thread safe. Since all
changes in a project will be using the same one, we can just
synchronize the function calls that modify that BatchRefUpdate.
Change-Id: I4af196fa720180b0846e9a6e7cc6d9083a75f695
2 files changed
