Multiprocessing warning in documentation (googleapis#4834)

chemelnucfin · web-flow · commit db4c151cdb9b · 2018-02-22T13:42:03.000-08:00
* Spanner: multiprocessing warning in documentation

* Review Changes
diff --git a/docs/spanner/usage.rst b/docs/spanner/usage.rst
@@ -87,6 +87,13 @@ Configuration
 
     Be sure to use the **Project ID**, not the **Project Number**.
 
+Warnings about Multiprocessing
+-------------------------------------------------
+- When using multiprocessing, the application may hang if a
+  :class:~google.cloud.spanner_v1.client.Client instance is created before
+  :class:multiprocessing.Pool or :class:multiprocessing.Process invokes :func:os.fork.
+  The issue is under investigation, but may be only happening on Macintosh and not Linux.
+  See `GRPC/GRPC#12455 <https://github.com/grpc/grpc/issues/12455#issuecomment-348578950>`_ for more information.
 
 Next Step
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