From eac31fc24a64a7a4a3a4ba3d412effb3e8ea519d Mon Sep 17 00:00:00 2001
From: bwarsaw
Date: Fri, 12 Sep 2003 13:47:12 +0000
Subject: SYNC_AFTER_WRITE: New flag which controls whether os.fsync() is
 called on the file descriptor for data files after they've been written.  We
 always flush the buffer, but sync'ing can be a huge performance hit. Still,
 some sites might want to enable this for additional data integrity.  It's
 disabled by default.

enqueue(): Return the newly calculated filebase.  This let's the shunt
message in Runner.py display the correct (new) filename.
---
 Mailman/Queue/Switchboard.py | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/Mailman/Queue/Switchboard.py b/Mailman/Queue/Switchboard.py
index 77179fcfe..4a56223d4 100644
--- a/Mailman/Queue/Switchboard.py
+++ b/Mailman/Queue/Switchboard.py
@@ -50,7 +50,20 @@ from Mailman.Logging.Syslog import syslog
 # 20 bytes of all bits set, maximum sha.digest() value
 shamax = 0xffffffffffffffffffffffffffffffffffffffffL
 
-SAVE_MSGS_AS_PICKLES = 1
+try:
+    True, False
+except NameError:
+    True = 1
+    False = 0
+
+# This flag causes Mailman to fsync() the file after writing and flushing its
+# contents.  While this ensures the data is written to disk, avoiding data
+# loss, it is a huge performance killer.
+SYNC_AFTER_WRITE = False
+# This flag causes messages to be written as pickles (when True) or text files
+# (when False).  Pickles are more efficient because the message doesn't need
+# to be re-parsed every time it's unqueued, but pickles are not human readable.
+SAVE_MSGS_AS_PICKLES = True
 
 
 
@@ -127,6 +140,7 @@ class _Switchboard:
         tmpfile = dbfile + '.tmp'
         self._ext_write(tmpfile, data)
         os.rename(tmpfile, dbfile)
+        return filebase
 
     def dequeue(self, filebase):
         # Calculate the .db and .msg filenames from the given filebase.
@@ -239,6 +253,10 @@ class MarshalSwitchboard(_Switchboard):
             else:
                 dict[attr] = repr(fval)
         marshal.dump(dict, fp)
+        # Make damn sure that the data we just wrote gets flushed to disk
+        fp.flush()
+        if SYNC_AFTER_WRITE:
+            os.fsync(fp.fileno())
         fp.close()
 
     def _ext_read(self, filename):
@@ -307,6 +325,10 @@ class ASCIISwitchboard(_Switchboard):
             os.umask(omask)
         for k, v in dict.items():
             print >> fp, '%s = %s' % (k, repr(v))
+        # Make damn sure that the data we just wrote gets flushed to disk
+        fp.flush()
+        if SYNC_AFTER_WRITE:
+            os.fsync(fp.fileno())
         fp.close()
 
     def _ext_read(self, filename):
-- 
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