CL-MEMCACHED
CL-MEMCACHED is a simple, fast & thread-safe library to interface with the memcached object caching system. It implements the Memcached TEXT protocol.
According to the home page :
memcached is a high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.
Tested on SBCL, CCL & CMUCL.
Global variables
*memcache*
Most commands have this as a fallback binding. Useful if we are only using one cache or if we want to bind it to a cache and then use it multiple places.
*mc-use-pool*
If this is true then the connection pool will be used. On SBCL this is about 3x faster.
*mc-default-encoding*
Babel is used for encodeing/decoding the data. Memcached expects octets. Default encoding is UTF-8.
make-memcache &key (ip "127.0.0.1") (port 11211) (name "Memcache") (pool-size 2)
Makes a memcached data-structure. We use this for further transactions. This has a inbuilt pool and know how to make new pool items.
mc-set key data &key (memcache *memcache*) (timeout 0) (flags 0) (noreply nil) (cas-unique nil) (mc-use-pool *mc-use-pool*)
Stores data for the key in the memcache. The parameters have same value as the memcached server commands.
We have similar mc-add, mc-replace, mc-append, mc-prepend functions available.
mc-cas key data cas-unique &key (memcache *memcache*) (timeout 0) (flags 0) (noreply nil) (external-format *mc-default-encoding*) (mc-use-pool *mc-use-pool*)
This is a Check & Store operation.
mc-get keys-list &key (memcache *memcache*) (mc-use-pool *mc-use-pool*)
Returns a list of lists corresponding to responses to found keys in the keys-list.
mc-get+ key-or-list-of-keys &key (memcache *memcache*) (mc-use-pool *mc-use-pool*)
This is a wrapper around mc-get. It accepts 1 or many keys. Returns 1 or many memcache-response type structures containing all the pieces of the response.
The memcache-response structure has these slots : key, flags, bytes, cas-unique, data-raw. All the slot accessors start with mc-
mc-data response &key (external-format *mc-default-encoding*)
Takes the data-raw, which is in octets, and converts it to string using the external-format.
mc-get-value key &key (memcache *memcache*) (mc-use-pool *mc-use-pool*) (external-format *mc-default-encoding*)
A wrapper around mc-data and mc-get+. Give it a key and it gets a string value in return. Misuse is entierly the users responsibility. :)
mc-del key &key (memcache *memcache*) (noreply nil) (mc-use-pool *mc-use-pool*)
Deletes key from the cache.
mc-incr key &key (value 1) (noreply nil) (memcache *memcache*) (mc-use-pool *mc-use-pool*)
Increments key in place by value. If key not found then will return NOT_FOUND.
mc-decr key &key (value 1) (noreply nil) (memcache *memcache*) (mc-use-pool *mc-use-pool*)
Decrements key by value. If key not found then will return NOT_FOUND.
mc-touch key expiry-time &key ( noreply nil ) ( memcache *memcache* ) ( mc-use-pool *mc-use-pool* )
Change expiry time of key.
mc-flush-all &key ( delay 0 ) ( noreply nil) ( memcache *memcache* ) ( mc-use-pool *mc-use-pool* )
expires all the current keys.
mc-version &key ( memcache *memcache* ) ( mc-use-pool *mc-use-pool* )
Returns a text string with the version of the memcached server
mc-verbosity &key ( level 1 ) ( noreply nil) ( memcache *memcache* ) ( mc-use-pool *mc-use-pool* )
Sets the verbosity level of the logging output
mc-stats &key (memcache *memcache*) (noreply nil) (mc-use-pool *mc-use-pool*)
Returns a alist of the stats.
mc-stats-summary &key (memcache *memcache*)
Prints all the details from the alist. ;) Not too hot, but hey.
Example Usage for testing.
CL-USER> (require 'cl-memcached)
NIL
CL-MEMCACHED> (in-package :cl-memcached)
#<PACKAGE "CL-MEMCACHED">
CL-MEMCACHED> (setf *memcache* (make-memcache))
#<MEMCACHED-SERVER Name:Memcache IP:127.0.0.1 Port:11211 >
CL-MEMCACHED> (mc-quick-test "foo" "bar")
Success SET
Success GET
NIL
CL-MEMCACHED> (mc-set "t1" "oooooooooooooooooooooo")
STORED
:INTERNAL
CL-MEMCACHED> (mc-get+ "t1")
#<MEMCACHED-RESPONSE Key:t1 Data-Length:22 >
CL-MEMCACHED> (describe *)
#<MEMCACHED-RESPONSE Key:t1 Data-Length:22 >
[structure-object]
Slots with :INSTANCE allocation:
KEY = "t1"
FLAGS = "0"
BYTES = 22
CAS-UNIQUE = NIL
DATA-RAW = #(111 111 111 111 111 111 111 111 111 111 111 111 111 111 111 111 111..
; No value
CL-MEMCACHED> (mc-data (mc-get+ "t1"))
"oooooooooooooooooooooo"
CL-MEMCACHED> (mc-get-value "t1")
"oooooooooooooooooooooo"
CL-MEMCACHED> (mc-set "t2" "0")
STORED
:INTERNAL
CL-MEMCACHED> (mc-incr "t3")
NOT_FOUND
CL-MEMCACHED> (mc-incr "t2")
1
1
CL-MEMCACHED> (mc-incr "t2")
2
1
CL-MEMCACHED> (mc-decr "t2")
1
1
AUTHORS:
Abhijit 'quasi' Rao quasi@quasilabs.in
DEPENDENCIES:
- usocket http://www.cliki.net/usockes
- split-sequence http://www.cliki.net/SPLIT-SEQUENCE
- babel http://common-lisp.net/project/babel/
- pooler https://github.com/quasi/pooler
Note : The http://common-lisp.net/project/cl-memcached/ is the homepage. But the version there is older and the documentation out of date. I have lost the creds, :-). Till I manage to set that right please ignore that one.
Benchmark
Host OS : OSX 10.8.4 Dataset: 1024 bytes (1kb) text string. Repeat 10000 times.
|-------------------+------------------+---------------+------------------+---------------|
| implementation | SET without pool | SET with pool | GET without pool | GET with pool |
|-------------------+------------------+---------------+------------------+---------------|
| SBCL 1.1.10 | 4.942 | 0.713 | 4.905 | 0.690 |
| CCL 1.9-r15759 | 4.711 | 0.847 | 4.506 | 0.648 |
| CMUCL 20D Unicode | 4.460 | 0.970 | 4.290 | 0.810 |
|-------------------+------------------+---------------+------------------+---------------|
| Dalli on Ruby 1.9 | | 0.957 | | 1.033 |
|-------------------+------------------+---------------+------------------+---------------|
When we do not use the pool we make a new socket connection every time.
The Ruby 'dalli' client, which implements the binary protocol, uses the same socket (I think) so this should be comparable with our with-pool.