Avoid useless or redundant db operations. Faster.

Moving operations into the "with self._connect" means less opening and
closing of the database.  Returning early if there is no data to write
avoids writing empty contexts.

1 files changed, 2 insertions, 0 deletions

diff --git a/CHANGES.rst b/CHANGES.rst
index 52ec0761..ec5fea2d 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -32,6 +32,8 @@ Unreleased
     information to each covered line.  Hovering over the "ctx" marker at the
     end of the line reveals a list of the contexts that covered the line.
 
+- Dynamic contexts with no data are no longer written to the database.
+
 - Added the classmethod :meth:`Coverage.current` to get the latest started
   `Coverage` instance.