+++ /dev/null
-# groupcache
-
-## Summary
-
-groupcache is a caching and cache-filling library, intended as a
-replacement for memcached in many cases.
-
-For API docs and examples, see http://godoc.org/github.com/golang/groupcache
-
-## Comparison to memcached
-
-### **Like memcached**, groupcache:
-
- * shards by key to select which peer is responsible for that key
-
-### **Unlike memcached**, groupcache:
-
- * does not require running a separate set of servers, thus massively
- reducing deployment/configuration pain. groupcache is a client
- library as well as a server. It connects to its own peers.
-
- * comes with a cache filling mechanism. Whereas memcached just says
- "Sorry, cache miss", often resulting in a thundering herd of
- database (or whatever) loads from an unbounded number of clients
- (which has resulted in several fun outages), groupcache coordinates
- cache fills such that only one load in one process of an entire
- replicated set of processes populates the cache, then multiplexes
- the loaded value to all callers.
-
- * does not support versioned values. If key "foo" is value "bar",
- key "foo" must always be "bar". There are neither cache expiration
- times, nor explicit cache evictions. Thus there is also no CAS,
- nor Increment/Decrement. This also means that groupcache....
-
- * ... supports automatic mirroring of super-hot items to multiple
- processes. This prevents memcached hot spotting where a machine's
- CPU and/or NIC are overloaded by very popular keys/values.
-
- * is currently only available for Go. It's very unlikely that I
- (bradfitz@) will port the code to any other language.
-
-## Loading process
-
-In a nutshell, a groupcache lookup of **Get("foo")** looks like:
-
-(On machine #5 of a set of N machines running the same code)
-
- 1. Is the value of "foo" in local memory because it's super hot? If so, use it.
-
- 2. Is the value of "foo" in local memory because peer #5 (the current
- peer) is the owner of it? If so, use it.
-
- 3. Amongst all the peers in my set of N, am I the owner of the key
- "foo"? (e.g. does it consistent hash to 5?) If so, load it. If
- other callers come in, via the same process or via RPC requests
- from peers, they block waiting for the load to finish and get the
- same answer. If not, RPC to the peer that's the owner and get
- the answer. If the RPC fails, just load it locally (still with
- local dup suppression).
-
-## Users
-
-groupcache is in production use by dl.google.com (its original user),
-parts of Blogger, parts of Google Code, parts of Google Fiber, parts
-of Google production monitoring systems, etc.
-
-## Presentations
-
-See http://talks.golang.org/2013/oscon-dl.slide
-
-## Help
-
-Use the golang-nuts mailing list for any discussion or questions.
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