Merge branch 'stable-3.1' into stable-3.2

* stable-3.1:
  Update git submodules
  Update git submodules
  Update git submodules
  Schema_146: Disable bitmap index re-build during full gc
  Schema_154: Disable bitmap index re-build during full gc
  Schema_154: Periodically run full gc
  Schema_146: Periodically run full gc
  Revert "Keep alive database connection to prevent exceeding wait timeout"

Change-Id: I303494eb6fbbb59500635321f2920955ddfb652f