Active rehashing

1 files changed, 20 insertions, 0 deletions

diff --git a/redis.conf b/redis.conf
index 3b9a8e224..c9ff26cf9 100644
--- a/redis.conf
+++ b/redis.conf
@@ -262,6 +262,26 @@ glueoutputbuf yes
 hash-max-zipmap-entries 64
 hash-max-zipmap-value 512
 
+# Active rehashing uses 1 millisecond every 100 milliseconds of CPU time in
+# order to help rehashing the main Redis hash table (the one mapping top-level
+# keys to values). The hash table implementation redis uses (see dict.c)
+# performs a lazy rehashing: the more operation you run into an hash table
+# that is rhashing, the more rehashing "steps" are performed, so if the
+# server is idle the rehashing is never complete and some more memory is used
+# by the hash table.
+# 
+# The default is to use this millisecond 10 times every second in order to
+# active rehashing the main dictionaries, freeing memory when possible.
+#
+# If unsure:
+# use "activerehashing no" if you have hard latency requirements and it is
+# not a good thing in your environment that Redis can reply form time to time
+# to queries with 2 milliseconds delay.
+#
+# use "activerehashing yes" if you don't have such hard requirements but
+# want to free memory asap when possible.
+activerehashing yes
+
 ################################## INCLUDES ###################################
 
 # Include one or more other config files here.  This is useful if you