一. memcached install
prefix: download memcached and libmemcached sources
1. libevent
cd libevent-1.4.13-stable/
./configure --prefix=/usr ##默认/usr/local
make
sudo make install
2. memcached
cd memcached-1.4.5
./configure
make
sudo make install
二. use memcached.
memcached -h
memcached 1.4.5
-p <num> TCP port number to listen on (default: 11211)
-U <num> UDP port number to listen on (default: 11211, 0 is off)
-s <file> UNIX socket path to listen on (disables network support)
-a <mask> access mask for UNIX socket, in octal (default: 0700)
-l <ip_addr> interface to listen on (default: INADDR_ANY, all addresses)
-d run as a daemon
-r maximize core file limit
-u <username> assume identity of <username> (only when run as root)
-m <num> max memory to use for items in megabytes (default: 64 MB)
-M return error on memory exhausted (rather than removing items)
-c <num> max simultaneous connections (default: 1024)
-k lock down all paged memory. Note that there is a
limit on how much memory you may lock. Trying to
allocate more than that would fail, so be sure you
set the limit correctly for the user you started
the daemon with (not for -u <username> user;
under sh this is done with 'ulimit -S -l NUM_KB').
-v verbose (print errors/warnings while in event loop)
-vv very verbose (also print client commands/reponses)
-vvv extremely verbose (also print internal state transitions)
-h print this help and exit
-i print memcached and libevent license
-P <file> save PID in <file>, only used with -d option
-f <factor> chunk size growth factor (default: 1.25)
-n <bytes> minimum space allocated for key+value+flags (default: 48)
-L Try to use large memory pages (if available). Increasing
the memory page size could reduce the number of TLB misses
and improve the performance. In order to get large pages
from the OS, memcached will allocate the total item-cache
in one large chunk.
-D <char> Use <char> as the delimiter between key prefixes and IDs.
This is used for per-prefix stats reporting. The default is
":" (colon). If this option is specified, stats collection
is turned on automatically; if not, then it may be turned on
by sending the "stats detail on" command to the server.
-t <num> number of threads to use (default: 4)
-R Maximum number of requests per event, limits the number of
requests process for a given connection to prevent
starvation (default: 20)
-C Disable use of CAS
-b Set the backlog queue limit (default: 1024)
-B Binding protocol - one of ascii, binary, or auto (default)
-I Override the size of each slab page. Adjusts max item size
(default: 1mb, min: 1k, max: 128m)
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memcached -vv
slab class 1: chunk size 80 perslab 13107
slab class 2: chunk size 104 perslab 10082
slab class 3: chunk size 136 perslab 7710
slab class 4: chunk size 176 perslab 5957
slab class 5: chunk size 224 perslab 4681
slab class 6: chunk size 280 perslab 3744
slab class 7: chunk size 352 perslab 2978
slab class 8: chunk size 440 perslab 2383
slab class 9: chunk size 552 perslab 1899
slab class 10: chunk size 696 perslab 1506
slab class 11: chunk size 872 perslab 1202
slab class 12: chunk size 1096 perslab 956
slab class 13: chunk size 1376 perslab 762
slab class 14: chunk size 1720 perslab 609
slab class 15: chunk size 2152 perslab 487
slab class 16: chunk size 2696 perslab 388
slab class 17: chunk size 3376 perslab 310
slab class 18: chunk size 4224 perslab 248
slab class 19: chunk size 5280 perslab 198
slab class 20: chunk size 6600 perslab 158
slab class 21: chunk size 8256 perslab 127
slab class 22: chunk size 10320 perslab 101
slab class 23: chunk size 12904 perslab 81
slab class 24: chunk size 16136 perslab 64
slab class 25: chunk size 20176 perslab 51
slab class 26: chunk size 25224 perslab 41
slab class 27: chunk size 31536 perslab 33
slab class 28: chunk size 39424 perslab 26
slab class 29: chunk size 49280 perslab 21
slab class 30: chunk size 61600 perslab 17
slab class 31: chunk size 77000 perslab 13
slab class 32: chunk size 96256 perslab 10
slab class 33: chunk size 120320 perslab 8
slab class 34: chunk size 150400 perslab 6
slab class 35: chunk size 188000 perslab 5
slab class 36: chunk size 235000 perslab 4
slab class 37: chunk size 293752 perslab 3
slab class 38: chunk size 367192 perslab 2
slab class 39: chunk size 458992 perslab 2
slab class 40: chunk size 573744 perslab 1
slab class 41: chunk size 717184 perslab 1
slab class 42: chunk size 1048576 perslab 1
<26 server listening (auto-negotiate)
<27 server listening (auto-negotiate)
<28 send buffer was 112640, now 268435456
<29 send buffer was 112640, now 268435456
<28 server listening (udp)
<28 server listening (udp)
<28 server listening (udp)
<29 server listening (udp)
<28 server listening (udp)
<29 server listening (udp)
<29 server listening (udp)
<29 server listening (udp)
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三. 简单使用memcached
1. telnet测试
先看一下memcached的protocol吧(source/doc/protocol.txt)：
Storage commands
----------------
First, the client sends a command line which looks like this:
<command name> <key> <flags> <exptime> <bytes> [noreply]\r\n
cas <key> <flags> <exptime> <bytes> <cas unique> [noreply]\r\n
- <command name> is "set", "add", "replace", "append" or "prepend"
"set" means "store this data".
"add" means "store this data, but only if the server *doesn't* already
hold data for this key".
"replace" means "store this data, but only if the server *does*
already hold data for this key".
"append" means "add this data to an existing key after existing data".
"prepend" means "add this data to an existing key before existing data".
The append and prepend commands do not accept flags or exptime.
They update existing data portions, and ignore new flag and exptime
settings.
"cas" is a check and set operation which means "store this data but
only if no one else has updated since I last fetched it."
- <key> is the key under which the client asks to store the data
- <flags> is an arbitrary 16-bit unsigned integer (written out in
decimal) that the server stores along with the data and sends back
when the item is retrieved. Clients may use this as a bit field to
store data-specific information; this field is opaque to the server.
Note that in memcached 1.2.1 and higher, flags may be 32-bits, instead
of 16, but you might want to restrict yourself to 16 bits for
compatibility with older versions.
- <exptime> is expiration time. If it's 0, the item never expires
(although it may be deleted from the cache to make place for other
items). If it's non-zero (either Unix time or offset in seconds from
current time), it is guaranteed that clients will not be able to
retrieve this item after the expiration time arrives (measured by
server time).
- <bytes> is the number of bytes in the data block to follow, *not*
including the delimiting \r\n. <bytes> may be zero (in which case
it's followed by an empty data block).
- is a unique 64-bit value of an existing entry.
Clients should use the value returned from the "gets" command
when issuing "cas" updates.
- "noreply" optional parameter instructs the server to not send the
reply. NOTE: if the request line is malformed, the server can't
parse "noreply" option reliably. In this case it may send the error
to the client, and not reading it on the client side will break
things. Client should construct only valid requests.
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$ telnet localhost 11211
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
set key1 0 300 5
abcde
STORED
get key1
VALUE key1 0 5
abcde
END
set key2 0 300 10
aaabbbcccd
STORED
get key2
VALUE key2 0 10
aaabbbcccd
END
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set 第一个参数是key, 然后是flag(0), expiretime(300s), value_len(5bytes)
2. 用libmemcached测试(C++ library)
1)install libmemcached
cd libmemcached-0.43/
./configure --prefix=/usr
make && make install
2) memtest.c
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <libmemcached/memcached.h>
//compile:gcc -o memtest2 memtest2.c -Wall -g -lmemcached
int main(int argc, char *argv[])
{
memcached_st *mc;
memcached_return_t rc;
memcached_server_st *servers;
char vbuf[1024] = {0};
mc = memcached_create(NULL);
servers = memcached_server_list_append(NULL, "localhost", 11211, &rc);
rc = memcached_server_push(mc, servers);
strcpy(vbuf, "This is the first value of key1");
char *key1 = "key1";
rc = memcached_set(mc, key1, strlen(key1), vbuf, strlen(vbuf), (time_t)180, (uint32_t)0);
if (rc == MEMCACHED_SUCCESS){
printf("Store %s->%s\n", key1, vbuf);
}
char *vptr;
size_t vlen;
uint32_t vflag;
vptr = memcached_get(mc, key1, strlen(key1), &vlen, &vflag, &rc);
if (rc == MEMCACHED_SUCCESS){
printf("Get %s->%s\n", key1, vptr);
}
memcached_free(mc);
memcached_server_free(servers);
return 0;
}
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./memtest
Store key1->This is the first value of key1
Get key1->This is the first value of key1
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