安装Memcached
// 安装libevent
$ wget https://github.com/downloads/libevent/libevent/libevent-1.4.14b-stable.tar.gz
$ tar zxvf libevent-1.4.14b-stable.tar.gz
$ cd libevent-1.4.14b-stable
$./configure --prefix=/usr/local
$ make
# make install
// 安装memcached
$wget http://Memcached.googlecode.com/files/Memcached-1.4.22.tar.gz
$ tar zxvf Memcached-1.4.22.tar.gz
$ cd Memcached-1.4.22
$ ./configure --with-libevent=/usr/local
$ make
# make install
设置代理
yum 代理
# vi /etc/profile
在文件末尾添加
proxy=http://trend\xandy_xu:shun#1211@cnnjproxy-ha.tw.trendnet.org:8080
安装telnet
#yum install telnet-server
#yum install telnet
测试
$ /usr/local/bin/memcached -d -vvv
$ telnet localhost 11211
[root@nj-grey-guo xandy]# telnet localhost 11211
Trying ::1...
Connected to localhost.
Escape character is '^]'.
注：ping和ssh都可以连得上，若telnet连接memcached server连接不上，则需要将防火墙关闭。 网上找了好久的资料，终于将这个问题解决了。
# iptables -F
存储命令
命令格式： <command name> <key> <flags> <exptime> <bytes> <data block> 命令解释: <command name> set/add/replace <key> 查找关键字 <flags> 客户机使用它存储关于键值对的额外信息 <exptime> 该数据的存活时间,0为永远 <bytes> 存储字节数 <data block> 存储的数据块
set server 0 0 9
localhost
STORED
add port 0 0 4
8080
STORED
get server
VALUE server 0 9
localhost
END
get port
VALUE port 0 4
8080
END
replace server 0 0 11
10.64.40.12
STORED
get server port
VALUE server 0 11
10.64.40.12
VALUE port 0 4
8080
END
set 无论如何都进行存储 add 只有数据不存在时进行添加 repalce 只有数据存在时进行替换
读取命令
get <key> <key>可以表示一个或多个键值，由空格隔开的字串
删除命令
delete <key> 删除键值为key的数据。
delete port
DELETED
状态命令
stats
stat
STAT pid 2769
STAT uptime 3347
STAT time 1423311919
STAT version 1.4.22
STAT libevent 1.4.14b-stable
STAT pointer_size 64
STAT rusage_user 0.068989
STAT rusage_system 0.109983
STAT curr_connections 11
STAT total_connections 15
STAT connection_structures 12
STAT reserved_fds 20
STAT cmd_get 26
STAT cmd_set 11
STAT cmd_flush 0
STAT cmd_touch 0
STAT get_hits 22
STAT get_misses 4
STAT delete_misses 0
STAT delete_hits 1
STAT incr_misses 0
STAT incr_hits 0
STAT decr_misses 0
STAT decr_hits 0
STAT cas_misses 0
STAT cas_hits 0
STAT cas_badval 0
STAT touch_hits 0
STAT touch_misses 0
STAT auth_cmds 0
STAT auth_errors 0
STAT bytes_read 1016
STAT bytes_written 1125
STAT limit_maxbytes 67108864
STAT accepting_conns 1
STAT listen_disabled_num 0
STAT threads 4
STAT conn_yields 0
STAT hash_power_level 16
STAT hash_bytes 524288
STAT hash_is_expanding 0
STAT malloc_fails 0
STAT bytes 155
STAT curr_items 2
STAT total_items 8
STAT expired_unfetched 0
STAT evicted_unfetched 0
STAT evictions 0
STAT reclaimed 0
STAT crawler_reclaimed 0
STAT lrutail_reflocked 0
END
debug Memecached
$ cd Memcached-1.4.22
#make uninstall
$ ./configure --with-libevent=/usr/local
$make CFLAGS="-g -O0"
$make install
Memcached对每一个存取操作都是加锁的。
(gdb) i breakpoint
Num Type Disp Enb Address What
1 breakpoint keep y 0x000000000040f478 in main at memcached.c:5027
breakpoint already hit 1 time
2 breakpoint keep y 0x000000000041376c in do_item_alloc at items.c:95
breakpoint already hit 5 times
3 breakpoint keep y 0x000000000041418d in do_item_link at items.c:317
breakpoint already hit 5 times
4 breakpoint keep y 0x000000000041458c in do_item_update at items.c:395
breakpoint already hit 1 time
5 breakpoint keep y 0x0000000000414600 in do_item_replace at items.c:413
breakpoint already hit 2 times
6 breakpoint keep y 0x00000000004153e8 in do_item_get at items.c:576
breakpoint already hit 7 times
7 breakpoint keep y 0x0000000000416453 in assoc_init at assoc.c:63
breakpoint already hit 1 time
8 breakpoint keep y 0x0000000000416514 in assoc_find at assoc.c:81
breakpoint already hit 7 times
9 breakpoint keep y 0x0000000000416879 in assoc_insert at assoc.c:160
breakpoint already hit 5 times
10 breakpoint keep y 0x00000000004169be in assoc_delete at assoc.c:180
breakpoint already hit 2 times
11 breakpoint keep y 0x0000000000417327 in create_worker at thread.c:307
breakpoint already hit 4 times
12 breakpoint keep y 0x000000000041739e in accept_new_conns at thread.c:320
13 breakpoint keep y 0x00000000004173cc in setup_thread at thread.c:330
breakpoint already hit 4 times
14 breakpoint keep y 0x00000000004175dc in thread_libevent_process at thread.c:388
breakpoint already hit 9 times
15 breakpoint keep y 0x00000000004178e3 in item_get at thread.c:493
breakpoint already hit 2 times
16 breakpoint keep y 0x0000000000417b54 in item_update at thread.c:562
breakpoint already hit 1 time
17 breakpoint keep y 0x0000000000417d61 in item_stats at thread.c:625
18 breakpoint keep y 0x0000000000418ade in memcached_thread_init at thread.c:772
breakpoint already hit 1 time
19 breakpoint keep y 0x0000000000411401 in slabs_init at slabs.c:96
breakpoint already hit 1 time
20 breakpoint keep y 0x0000000000411877 in do_slabs_newslab at slabs.c:196
breakpoint already hit 1 time
(gdb) bt
#0 process_get_command (c=0x7fffe00261c0, tokens=0x7ffff7d24b50, ntokens=3, return_cas=false) at memcached.c:2877
#1 0x000000000040bc55 in process_command (c=0x7fffe00261c0, command=0x7fffe00263d0 "get") at memcached.c:3433
#2 0x000000000040cba6 in try_read_command (c=0x7fffe00261c0) at memcached.c:3768
#3 0x000000000040d8b9 in drive_machine (c=0x7fffe00261c0) at memcached.c:4113
#4 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#5 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#6 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#7 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#8 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#9 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) i threads
6 Thread 0x7ffff5521700 (LWP 6074) 0x0000003bce00b5bc in pthread_cond_wait@@GLIBC_2.3.2 ()
from /lib64/libpthread.so.0
5 Thread 0x7ffff5f22700 (LWP 6073) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
4 Thread 0x7ffff6923700 (LWP 6071) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
3 Thread 0x7ffff7324700 (LWP 6069) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
* 2 Thread 0x7ffff7d25700 (LWP 6068) process_get_command (c=0x7fffe00261c0, tokens=0x7ffff7d24b50, ntokens=3,
return_cas=false) at memcached.c:2877
1 Thread 0x7ffff7dd1700 (LWP 5794) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
set hi 0 0 7
welcome
(gdb) bt
#0 do_item_get (key=0x7ffff4b20e28 "hi", nkey=2, hv=1421556408) at items.c:576
#1 0x0000000000407e5e in do_store_item (it=0x7ffff4b20df0, comm=2, c=0x7fffe00261c0, hv=1421556408) at memcached.c:2290
#2 0x0000000000417cd8 in store_item (item=0x7ffff4b20df0, comm=2, c=0x7fffe00261c0) at thread.c:595
#3 0x000000000040473b in complete_nread_ascii (c=0x7fffe00261c0) at memcached.c:896
#4 0x0000000000407dda in complete_nread (c=0x7fffe00261c0) at memcached.c:2276
#5 0x000000000040d9ec in drive_machine (c=0x7fffe00261c0) at memcached.c:4151
#6 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#7 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#8 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#9 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#10 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#11 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) bt
#0 assoc_insert (it=0x7ffff4b20df0, hv=1421556408) at assoc.c:166
#1 0x000000000041427f in do_item_link (it=0x7ffff4b20df0, hv=1421556408) at items.c:329
#2 0x000000000040854c in do_store_item (it=0x7ffff4b20df0, comm=2, c=0x7fffe00261c0, hv=1421556408) at memcached.c:2385
#3 0x0000000000417cd8 in store_item (item=0x7ffff4b20df0, comm=2, c=0x7fffe00261c0) at thread.c:595
#4 0x000000000040473b in complete_nread_ascii (c=0x7fffe00261c0) at memcached.c:896
#5 0x0000000000407dda in complete_nread (c=0x7fffe00261c0) at memcached.c:2276
#6 0x000000000040d9ec in drive_machine (c=0x7fffe00261c0) at memcached.c:4151
#7 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#8 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#9 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#10 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#11 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#12 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb)
930 out_string(c, "STORED");
(gdb) bt
#0 complete_nread_ascii (c=0x7fffe00261c0) at memcached.c:930
#1 0x0000000000407dda in complete_nread (c=0x7fffe00261c0) at memcached.c:2276
#2 0x000000000040d9ec in drive_machine (c=0x7fffe00261c0) at memcached.c:4151
#3 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#4 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#5 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#6 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#7 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#8 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) bt
#0 drive_machine (c=0x7fffe00261c0) at memcached.c:4269
#1 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#2 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#3 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#4 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#5 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#6 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) i threads
6 Thread 0x7ffff5521700 (LWP 6074) 0x0000003bce00b5bc in pthread_cond_wait@@GLIBC_2.3.2 ()
from /lib64/libpthread.so.0
5 Thread 0x7ffff5f22700 (LWP 6073) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
4 Thread 0x7ffff6923700 (LWP 6071) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
3 Thread 0x7ffff7324700 (LWP 6069) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
* 2 Thread 0x7ffff7d25700 (LWP 6068) drive_machine (c=0x7fffe00261c0) at memcached.c:4269
1 Thread 0x7ffff7dd1700 (LWP 5794) 0x0000003bcdce8fd3 in epoll_wait () from /lib64/libc.so.6
delete hi
3413 fprintf(stderr, "<%d %s\n", c->sfd, command);
(gdb) p command
$33 = 0x7fffe00263d0 "delete hi"
(gdb) bt
#0 process_command (c=0x7fffe00261c0, command=0x7fffe00263d0 "delete hi") at memcached.c:3413
#1 0x000000000040cba6 in try_read_command (c=0x7fffe00261c0) at memcached.c:3768
#2 0x000000000040d8b9 in drive_machine (c=0x7fffe00261c0) at memcached.c:4113
#3 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#4 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#5 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#6 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#7 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#8 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) bt
#0 process_delete_command (c=0x7fffe00261c0, tokens=0x7ffff7d24b50, ntokens=3) at memcached.c:3324
#1 0x000000000040beb8 in process_command (c=0x7fffe00261c0, command=0x7fffe00263d0 "delete") at memcached.c:3462
#2 0x000000000040cba6 in try_read_command (c=0x7fffe00261c0) at memcached.c:3768
#3 0x000000000040d8b9 in drive_machine (c=0x7fffe00261c0) at memcached.c:4113
#4 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#5 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#6 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#7 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#8 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#9 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) bt
#0 do_item_unlink (it=0x7ffff4b20df0, hv=1421556408) at items.c:339
#1 0x0000000000417b36 in item_unlink (item=0x7ffff4b20df0) at thread.c:553
#2 0x000000000040b99c in process_delete_command (c=0x7fffe00261c0, tokens=0x7ffff7d24b50, ntokens=3)
at memcached.c:3357
#3 0x000000000040beb8 in process_command (c=0x7fffe00261c0, command=0x7fffe00263d0 "delete") at memcached.c:3462
#4 0x000000000040cba6 in try_read_command (c=0x7fffe00261c0) at memcached.c:3768
#5 0x000000000040d8b9 in drive_machine (c=0x7fffe00261c0) at memcached.c:4113
#6 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#7 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#8 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#9 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#10 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#11 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) p *it
$45 = {next = 0x7ffff4b20e50, prev = 0x0, h_next = 0x0, time = 1723, exptime = 0, nbytes = 9, refcount = 2,
nsuffix = 6 '\006', it_flags = 11 '\v', slabs_clsid = 1 '\001', nkey = 2 '\002', data = 0x7ffff4b20df0}
(gdb) ptype it
type = struct _stritem {
struct _stritem *next;
struct _stritem *prev;
struct _stritem *h_next;
rel_time_t time;
rel_time_t exptime;
int nbytes;
short unsigned int refcount;
uint8_t nsuffix;
uint8_t it_flags;
uint8_t slabs_clsid;
uint8_t nkey;
union {
uint64_t cas;
char end;
} data[];
} *
Breakpoint 10, assoc_delete (key=0x7ffff4b20e28 "hi", nkey=2, hv=1421556408) at assoc.c:180
180 item **before = _hashitem_before(key, nkey, hv);
(gdb) bt
#0 assoc_delete (key=0x7ffff4b20e28 "hi", nkey=2, hv=1421556408) at assoc.c:180
#1 0x00000000004143b3 in do_item_unlink (it=0x7ffff4b20df0, hv=1421556408) at items.c:346
#2 0x0000000000417b36 in item_unlink (item=0x7ffff4b20df0) at thread.c:553
#3 0x000000000040b99c in process_delete_command (c=0x7fffe00261c0, tokens=0x7ffff7d24b50, ntokens=3)
at memcached.c:3357
#4 0x000000000040beb8 in process_command (c=0x7fffe00261c0, command=0x7fffe00263d0 "delete") at memcached.c:3462
#5 0x000000000040cba6 in try_read_command (c=0x7fffe00261c0) at memcached.c:3768
#6 0x000000000040d8b9 in drive_machine (c=0x7fffe00261c0) at memcached.c:4113
#7 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#8 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#9 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#10 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#11 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#12 0x0000003bcdce89dd in clone () from /lib64/libc.so.6
(gdb) ptype key
type = const char *
(gdb) p key
$46 = 0x7ffff4b20e28 "hi"
分配空间，然后再读取。
set comany 0 0 11
Trend Micro
(gdb) p *c
$48 = {sfd = 40, sasl_conn = 0x0, authenticated = false, state = conn_parse_cmd, substate = bin_no_state,
last_cmd_time = 4651, event = {ev_next = {tqe_next = 0x0, tqe_prev = 0x7fffe0013560}, ev_active_next = {
tqe_next = 0x0, tqe_prev = 0x63d290}, ev_signal_next = {tqe_next = 0x0, tqe_prev = 0x0},
min_heap_idx = 4294967295, ev_base = 0x63c870, ev_fd = 40, ev_events = 18, ev_ncalls = 0,
ev_pncalls = 0x7ffff7d24e4e, ev_timeout = {tv_sec = 0, tv_usec = 0}, ev_pri = 0,
ev_callback = 0x40e3a8 <event_handler>, ev_arg = 0x7fffe00261c0, ev_res = 2, ev_flags = 130}, ev_flags = 18,
which = 2, rbuf = 0x7fffe00263d0 "set company 0 0 11", rcurr = 0x7fffe00263d0 "set company 0 0 11", rsize = 2048,
rbytes = 20, wbuf = 0x7fffe0026be0 "ERROR\r\n\r\nROR bad command line format\r\n",
wcurr = 0x7fffe00296d0 "STAT pid 5794\r\nSTAT uptime 3112\r\nSTAT time 1423478618\r\nSTAT version 1.4.22\r\nSTAT libevent 1.4.14b-stable\r\nSTAT pointer_size 64\r\nSTAT rusage_user 0.017997\r\nSTAT rusage_system 3.215511\r\nSTAT curr_connec"..., wsize = 2048, wbytes = 1106, write_and_go = conn_new_cmd, write_and_free = 0x0, ritem = 0x7ffff4b20e3a "",
rlbytes = 0, item = 0x0, sbytes = 0, iov = 0x7fffe0027af0, iovsize = 400, iovused = 4, msglist = 0x7fffe0029400,
msgsize = 10, msgused = 1, msgcurr = 1, msgbytes = 37, ilist = 0x7fffe00273f0, isize = 200, icurr = 0x7fffe00273f0,
ileft = 0, suffixlist = 0x7fffe0027a40, suffixsize = 20, suffixcurr = 0x7fffe0027a40, suffixleft = 0,
protocol = ascii_prot, transport = tcp_transport, request_id = 0, request_addr = {sin6_family = 2, sin6_port = 49642,
sin6_flowinfo = 86523914, sin6_addr = {__in6_u = {__u6_addr8 = '\000' <repeats 15 times>, __u6_addr16 = {0, 0, 0,
0, 0, 0, 0, 0}, __u6_addr32 = {0, 0, 0, 0}}}, sin6_scope_id = 0}, request_addr_size = 16, hdrbuf = 0x0,
hdrsize = 0, noreply = false, stats = {buffer = 0x0, size = 2048, offset = 1106}, binary_header = {request = {
magic = 0 '\000', opcode = 0 '\000', keylen = 0, extlen = 0 '\000', datatype = 0 '\000', reserved = 0,
bodylen = 0, opaque = 0, cas = 0}, bytes = '\000' <repeats 23 times>}, cas = 7, cmd = -1, opaque = 0, keylen = 0,
next = 0x0, thread = 0x62fa60}
(gdb) bt
#0 process_command (c=0x7fffe00261c0, command=0x7fffe00263d0 "set company 0 0 11") at memcached.c:3412
#1 0x000000000040cba6 in try_read_command (c=0x7fffe00261c0) at memcached.c:3768
#2 0x000000000040d8b9 in drive_machine (c=0x7fffe00261c0) at memcached.c:4113
#3 0x000000000040e427 in event_handler (fd=40, which=2, arg=0x7fffe00261c0) at memcached.c:4358
#4 0x00007ffff7de8c29 in event_process_active (base=0x63c870, flags=<value optimized out>) at event.c:395
#5 event_base_loop (base=0x63c870, flags=<value optimized out>) at event.c:547
#6 0x00000000004175bf in worker_libevent (arg=0x62fa60) at thread.c:378
#7 0x0000003bce0079d1 in start_thread () from /lib64/libpthread.so.0
#8 0x0000003bcdce89dd in clone () from /lib64/libc.so.6