syncbase: support restarts

MultiPart: 1/2

Implementation notes:
- Currently, I reinit in-memory data structures
  (apps and dbs maps) at syncbase startup.
- Testing strategy: v23 integration test starts a
  syncbase instance, writes to it, verifies what's
  written, restarts it, and verifies what's written
  a second time.
- Eventually we'll need to avoid having too many DBs
  open and running out of file descriptors or some
  other resource. The plan (discussed a bit with Bindu
  and Raja) is to do this by replacing DB's store.Store
  with a wrapper that handles store paging. I've added
  a TODO for this.

Change-Id: Iec64eee3971162104127d4732595d796fc17fcbe
11 files changed
tree: 3f97f41b5f7025923d6ea5c62063341146efbef4
  1. services/