Add a small note about the performance implications of complicated

ratelimit setups.

diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index 7938870650aea9a9aeef1883f294dd9c8325cd73..6ef8f2855ec0414669b863547d288aa8fa7c9354 100644 (file)
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.53 2005/06/27 14:34:33 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.54 2005/06/29 14:29:05 fanf2 Exp $
 
 New Features in Exim
 --------------------
@@ -235,6 +235,14 @@ TF/04 There is a new ratelimit ACL condition which can be used to measure
                         cdb {DB/ratelimits.cdb} \
                         {$value} {RATELIMIT} }
 
+      Warning: if you have a busy server with a lot of ratelimit tests,
+      especially with the per_rcpt option, you may suffer from a performance
+      bottleneck caused by locking on the ratelimit hints database. Apart from
+      making your ACLs less complicated, you can reduce the problem by using a
+      RAM disk for Exim's hints directory, /var/spool/exim/db/. However this
+      means that Exim will lose its hints data after a reboot (including retry
+      hints, the callout cache, and ratelimit data).
+
 TK/01 Added an 'spf' lookup type that will return an SPF result for a given
       email address (the key) and an IP address (the database):