@@ -1,3 +1,14 @@ += Unreleased + +* Implement a consistent hashing algorithm, as described in libketama. + This dramatically reduces the cost of adding or removing servers dynamically + as keys are much more likely to map to the same server. + + Take a scenario where we add a fourth server. With a dumb modulo algorithm, about + 25% of the keys will map to the same server. In other words, 75% of your memcached + content suddenly becomes invalid. With a consistent algorithm, 75% of the keys + will map to the same server as before - only 25% will be invalidated. + = 1.5.0.5 * Remove native C CRC32_ITU_T extension in favor of Zlib's crc32 method. History.txt @@ -46,9 +46,3 @@ memcache-client also comes with a wrapper called Cache in memcache_util.rb for use with Rails. To use it be sure to assign your memcache connection to CACHE. Cache returns nil on all memcache errors so you don't have to rescue the errors yourself. It has #get, #put and #delete module functions. - -=== Improving Performance === - -Performing the CRC-32 ITU-T step to determine which server to use for a given key -is VERY slow in Ruby. RubyGems should compile a native library for performing this -operation when the gem is installed. README.txt 7e0744387b4136a4915cd914e79aec2497d505dc Mike Perham mperham@gmail.com http://github.com/fiveruns/memcache-client/commit/fad65897338b4fda5bd49b65132f83a846583415 fad65897338b4fda5bd49b65132f83a846583415 2009-01-13T22:38:58-08:00 2009-01-13T22:38:58-08:00 Update docs 47a3868f38df03263706566a3e67fe7d51fd2c67 Mike Perham mperham@gmail.com