MAX_DELIVERY_THREADS: new variable which controls the number of

threads used to deliver messages when recipient lists are broken into
multiple chunks.  Python must be built with threads support for this
to work.  Read the comments for details.

1 files changed, 14 insertions, 0 deletions

diff --git a/Mailman/Defaults.py.in b/Mailman/Defaults.py.in
index 623ad3bd8..5108a01fb 100644
--- a/Mailman/Defaults.py.in
+++ b/Mailman/Defaults.py.in
@@ -101,6 +101,20 @@ MAX_SPAWNS        = 40
 # transaction.
 SMTP_MAX_RCPTS = 500
 
+#
+# Maximum number of simulatenous subthreads that will be used for SMTP
+# delivery.  After the recipients list is chunked according to SMTP_MAX_RCPTS,
+# each chunk is handed off to the smptd by a separate such thread.  If your
+# Python interpreter was not built for threads, this feature is disabled.  You
+# can explicitly disable it in all cases by setting MAX_DELIVERY_THREADS to
+# 0.  This feature is only supported with the SMTPDirect DELIVERY_MODULE.
+#
+# NOTE: This is an experimental feature and limited testing shows that it may
+# in fact degrade performance, possibly due to Python's global interpreter
+# lock.
+MAX_DELIVERY_THREADS = 0
+
+#
 # Delivery module for the message pipeline.  See
 # Mailman/Handlers/HandlerAPI.py for details.  Unless overridden specifically
 # in that module, this handler is used for message delivery to the list, and