\/\/\u5ba2\u6237\u7aefA\u6267\u884c\u4ee5\u4e0b\u4ee3\u7801\n \/\/\u83b7\u53d6user1\u7684\u6027\u522b\uff0c\u5982\u679c\u6027\u522b\u662f\u7537\uff0c\u5934\u50cf\u8bbe\u7f6e\u4e3a\u7537\u6027\u89d2\u8272\n \/\/\u5426\u5219\u5934\u50cf\u8bbe\u7f6e\u4e3a\u5973\u6027\u89d2\u8272\n gender =<\/span>redis->get('user1_gender');\n if(gender === 'male'){<\/span>redis->set('user1_photo','male.png');\n }else{\n $redis->set('user1_photo','female.png');\n }\n<\/code><\/pre>\n \/\/\u5ba2\u6237\u7aefB\u6267\u884c\u4ee5\u4e0b\u4ee3\u7801\n \/\/\u66f4\u6539user1\u7684\u6027\u522b\uff0c\u5982\u679c\u662f\u7537\u5219\u6539\u4e3a\u5973\uff0c\u5982\u679c\u662f\u5973\u5219\u6539\u4e3a\u7537\n \/\/\u5e76\u6839\u636e\u6027\u522b\u8bbe\u7f6e\u5934\u50cf\n gender =<\/span>redis->get('user1_gender');\n if(gender === 'male'){<\/span>redis->set('user1_gender','female');\n redis->set('user1_photo','female.png');\n }else{<\/span>redis->set('user1_gender','male');\n $redis->set('user1_photo','male.png');\n }\n\n<\/code><\/pre>\n\u5982\u679c\u5ba2\u6237\u7aefA\u3001B\u540c\u65f6\u53ea\u6709\u4e00\u4e2a\u6267\u884c\uff0c\u90a3\u4e48\u6027\u522b\u548c\u5934\u50cf\u4e00\u5b9a\u662f\u5bf9\u5e94\u7684\u3002\u4f46\u662fA\u3001B\u540c\u65f6\u6267\u884c\uff0c\u5e76\u4e14\u6267\u884c\u987a\u5e8f\u5982\u4e0b:
\n![\"\u65f6\u5e8f\u56fe\"](\"https:\/\/www.myway5.com\/wp-content\/uploads\/2018\/03\/%E6%B7%B1%E5%BA%A6%E6%88%AA%E5%9B%BE_%E9%80%89%E6%8B%A9%E5%8C%BA%E5%9F%9F_20180308151942.png\")
<\/p>\n
\u90a3\u4e48\u6267\u884c\u7ed3\u679c\u5c31\u662fuser1\u6027\u522b\u4e3a\u5973\uff0c\u4f46\u5934\u50cf\u4e3a\u7537\u6027\u89d2\u8272\u3002<\/p>\n
\u6240\u4ee5\u9488\u5bf9\u4e8e\u8fd9\u79cd\u60c5\u51b5\uff0c\u6211\u4eec\u9700\u8981\u4e00\u5b9a\u7684\u63aa\u65bd\u53bb\u9884\u9632\u3002<\/p>\n
redis\u7684\u4e8b\u52a1\u5b9e\u73b0\u65b9\u5f0f\u6709\u591a\u79cd\u3002\u636e\u6211\u6240\u77e5\u6709\u4e09\u79cd\u65b9\u5f0f\uff1a<\/p>\n
\n- 1.
MULTI<\/code>\/EXEC<\/code><\/li>\n- 2.
WATCH<\/code>\/UNWATCH<\/code><\/li>\n- 3.lua\u811a\u672c<\/li>\n<\/ul>\n
1.1 MULTI<\/code>\/EXEC<\/code><\/h3>\nMULTI<\/code>\/EXEC<\/code>\u662f\u6210\u5bf9\u51fa\u73b0\u7684\u6307\u4ee4\u3002\u5927\u5bb6\u90fd\u77e5\u9053\uff0credis\u6267\u884c\u6307\u4ee4\u662f\u5355\u7ebf\u7a0b\u7684\uff0c\u4e5f\u5c31\u662f\u8bf4\u6240\u6709\u6307\u4ee4\u90fd\u5904\u4e8e\u4e00\u4e2a\u961f\u5217\uff0c\u4e00\u4e2a\u4e00\u4e2a\u6267\u884c\u3002MULTI<\/code>\/EXEC<\/code>\u53ef\u4ee5\u4fdd\u8bc1\u6240\u6709\u7684\u6307\u4ee4\u90fd\u4f1a\u88ab\u540c\u65f6\u653e\u677e\u5230redis\u4e2d\uff0c\u4e2d\u95f4\u4e0d\u4f1a\u63ba\u6742\u6765\u81ea\u5176\u4ed6\u5ba2\u6237\u7aef\u7684\u6307\u4ee4\u3002<\/p>\n\u4f46\u662f\u8fd9\u4e2a\u9488\u5bf9\u4e8e\u4e0a\u8ff0\u60c5\u51b5\u5e76\u4e0d\u9002\u7528\u3002\u56e0\u4e3a\u6211\u4eec\u9700\u8981\u5728GET\u5230\u6570\u636e\u4e4b\u540e\uff0c\u624d\u80fd\u505a\u4e0b\u9762\u7684\u66f4\u65b0\u64cd\u4f5c\u3002<\/p>\n
1.2 WATCH<\/code>\/UNWATCH<\/code><\/h3>\n\u5728redis\u4e2d\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528watch\u6765\u76d1\u89c6\u4e00\u4e2a\u503c\u3002<\/p>\n
redis> WATCH name\nOK\n\nredis> MULTI\nOK\n\nredis> SET name peter\nQUEUED\n\nredis> EXEC\n(nil)\n<\/code><\/pre>\n\u6bd4\u5982\u8fd9\u6bb5\u4ee3\u7801\uff0c\u5728\u6211\u4eecWATCH name\u540e\uff0c\u5982\u679c\u53e6\u5916\u4e00\u4e2a\u5ba2\u6237\u7aef\u4fee\u6539\u4e86name\u7684\u503c\uff0c\u90a3\u4e48\u8fd9\u4e2a\u5ba2\u6237\u7aef\u518d\u6b21\u4fee\u6539name\u5219\u65e0\u6cd5\u6210\u529f\u3002\u8fd9\u5176\u5b9e\u5c31\u662f\u4e50\u89c2\u9501\u7684\u4e00\u79cd\u5b9e\u73b0\u3002\u5b83\u4fdd\u8bc1\u4e86\u4ee3\u7801\u7684\u6267\u884c\u7ed3\u679c\u4e0d\u4f1a\u9519\u4e71\u3002\u7528\u4e00\u5f00\u59cb\u7684\u4f8b\u5b50\u6765\u8bf4\uff0c\u5c31\u662f\u4e0d\u4f1a\u51fa\u73b0\u6027\u522b\u548c\u5934\u50cf\u4e0d\u5bf9\u5e94\u7684\u60c5\u51b5\u3002<\/p>\n
1.3 lua\u811a\u672c
\nredis\u4e2d\u53ef\u4ee5\u6267\u884clua\u811a\u672c\u6765\u5b8c\u6210\u4e8b\u52a1\u64cd\u4f5c\u3002lua\u811a\u672c\u548cMULTI\/EXEC\u5f88\u50cf\uff0c\u4e5f\u5c31\u662f\u8bf4\u5728lua\u811a\u672c\u6267\u884c\u7684\u8fc7\u7a0b\u4e2d\uff0credis\u662f\u4e0d\u6267\u884c\u5176\u4ed6\u5ba2\u6237\u7aef\u7684\u6307\u4ee4\u7684\u3002<\/p>\n
\u4f46\u662flua\u811a\u672c\u7684\u4e0d\u540c\u4e4b\u5904\u5728\u4e8e\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528GET\u64cd\u4f5c\u6765\u83b7\u53d6\u6570\u636e\u5e76\u5224\u65ad\uff0c\u518d\u6267\u884c\u540e\u6765\u7684\u64cd\u4f5c\u3002<\/p>\n
2.\u5728redis\u64cd\u4f5c\u4e2d\u4f7f\u7528\u9501<\/h2>\n
\u5728\u591a\u7ebf\u7a0b\u73af\u5883\u4e2d\uff0c\u4e3a\u4e86\u9632\u6b62\u8d44\u6e90\u51fa\u73b0race condition\uff0c\u9700\u8981\u501f\u52a9\u9501\u6765\u4e92\u65a5\u7684\u8bbf\u95ee\u8d44\u6e90\u3002\u5728\u8fd9\u91cc\u4e5f\u662f\u4e00\u6837\u7684\uff0cuser1_gender\u5c31\u662f\u6211\u4eec\u8981\u4e92\u65a5\u8bbf\u95ee\u7684\u8d44\u6e90\u3002<\/p>\n
\u8fd8\u662f\u4e0a\u8ff0\u90a3\u4e2a\u4f8b\u5b50\uff0c\u5982\u679c\u6211\u4eec\u4f7f\u7528\u60b2\u89c2\u9501\uff0c\u53ea\u6709\u83b7\u5f97\u9501\u7684\u5ba2\u6237\u7aef\u624d\u80fd\u8bfb\u53d6\u548c\u4fee\u6539user1\u7684\u7684\u503c\uff0c\u4e5f\u53ef\u4ee5\u5f88\u597d\u7684\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n
\u4f2a\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
$can_lock = lock('user1_gender'); \/\/\u5f97\u5230\u9501\nif($can_lock){\n do_something();\n $release_lock('user1_gender'); \/\/\u91ca\u653e\u9501\n}\n<\/code><\/pre>\n\u4e0d\u540c\u4e8e\u591a\u7ebf\u7a0b\u73af\u5883\u4e0b\u7684\u662f\uff0c\u6211\u4eec\u8fd9\u91cc\u7684\u9501\u7684\u8303\u56f4\u662f\u9488\u5bf9\u4e8e\u4e0d\u540c\u7684\u5ba2\u6237\u7aef\u3002\u56e0\u6b64\u6ca1\u6cd5\u4f7f\u7528\u57fa\u4e8e\u7cfb\u7edf\u7684\u3001\u6216\u8005\u57fa\u4e8e\u8bed\u8a00\u7684\u9501\uff0c\u800c\u662f\u5f97\u4f7f\u7528\u5206\u5e03\u5f0f\u7684\u9501\u3002\u8fd9\u6837\u7684\u5206\u5e03\u5f0f\u9501\u6211\u4eec\u540c\u6837\u53ef\u4ee5\u501f\u52a9\u4e8eredis\u6765\u5b9e\u73b0\u3002<\/p>\n
\u6574\u4e2a\u5206\u5e03\u5f0f\u9501\u7684\u5b9e\u73b0\u53ef\u4ee5\u6982\u62ec\u4e3a\u4ee5\u4e0b\u51e0\u4e2a\u6b65\u9aa4\uff1a<\/p>\n
\n- \n
\n- \u83b7\u5f97\u9501\u3002\u5f97\u5230\u8981\u9501\u7684\u8d44\u6e90\u7684\u552f\u4e00hash\uff1a
lockname<\/code>,\u4ee5\u53ca\u4e00\u4e2a\u968f\u673a\u5b57\u7b26\u4e32\uff1aidentifier<\/code>\uff0c\u8bbe\u7f6eexpire\uff1a20s,\u8fd9\u4e2aexpire\u5c31\u662f\u9501\u7684\u6709\u6548\u671f\uff0c\u5728\u6709\u6548\u671f\u540e\u9501\u4f1a\u81ea\u52a8\u91ca\u653e\uff0c\u9632\u6b62\u51fa\u73b0\u6b7b\u9501\u3002\u5728redis\u4e2d\u4f7f\u7528setnx(lockname,identifier,expire)\u3002\u8fd9\u53e5\u4ee3\u7801\u7684\u610f\u601d\u662f:\u5982\u679credis\u4e2d\u4e0d\u5b58\u5728lockname\uff0c\u5219\u5b58\u5165lockname\uff0c\u503c\u4e3aidentifier\uff0c\u8fc7\u671f\u65f6\u95f4\u662fexpire\u3002<\/li>\n<\/ol>\n<\/li>\n- \n
\n- \u7b2c\u4e00\u6b65\u6211\u4eec\u5c31\u5f97\u5230\u4e86\u4e00\u4e2a\u9501\uff0c\u8fd9\u4e00\u6b65\u6211\u4eec\u5f00\u59cb\u6267\u884c\u83b7\u5f97\u9501\u4e4b\u540e\u7684\u4ee3\u7801<\/li>\n<\/ol>\n<\/li>\n
- \n
\n- \u91ca\u653e\u9501\u3002\u6211\u4eec\u6839\u636elockname\u6765\u4eceredis\u4e2d\u67e5\u627e\u3002\u5982\u679cget(lockname) identifier\uff0c\u5219\u8868\u793a\u6211\u4eec\u4ecd\u7136\u6301\u6709\u8fd9\u628a\u9501\uff0c\u4f7f\u7528delete(lockname)\u6765\u91ca\u653e\u9501\u3002\u5982\u679c\u4e0d\u7b49\u4e8e\uff0c\u8bf4\u660e\u6211\u4eec\u5df2\u7ecf\u4e0d\u6301\u6709\u8fd9\u628a\u9501\u4e86\uff0c\u5219\u4ec0\u4e48\u4e5f\u4e0d\u505a\u3002<\/span><\/li>\n<\/ol>\n<\/li>\n<\/ul>\n
\u90a3\u4e48lock\u51fd\u6570\u53ef\u4ee5\u7528\u4ee5\u4e0b\u4ee3\u7801\u6765\u63cf\u8ff0:<\/p>\n
function lock(lockname,<\/span>identifier,expire = 20){<\/span>acquire_timeout = 10; \/\/\u82b1\u8d3910\u79d2\u53bb\u83b7\u5f97\u9501\uff0c\u5426\u5219\u5c31\u653e\u5f03\n end = time() +<\/span>acquire_timeout\n while (time() < end){<\/span>can_lock = redis->setnx(<\/span>lockname,identifier,<\/span>expire);\n if($can_lock){\n return true;\n }\n sleep(0.1);\n }\n\n return false;\n}\n<\/code><\/pre>\n function release_lock(lockname,<\/span>identifier){\n redis->watch(<\/span>lockname);\n try{\n if(redis->get(<\/span>lockname) === identifier){\n \/\/\u9501\u4ecd\u7136\u6301\u6709\uff0c\u91ca\u653e\u9501<\/span>redis->delete(lockname);\n return true;\n }<\/span>redis->unwatch();\n }catch(Exception $e){\n\n }\n\n return false;\n }\n<\/code><\/pre>\n\u8fd9\u6837\u6211\u4eec\u5c31\u5f88\u8f7b\u677e\u7684\u5f97\u5230\u4e86\u501f\u52a9\u4e8eredis\u5b9e\u73b0\u7684\u5206\u5e03\u5f0f\u9501\u3002\u4f46\u662f\u8fd9\u6837\u7684\u5b9e\u73b0\u65b9\u5f0f\u4f9d\u7136\u662f\u6709\u95ee\u9898\u7684\u3002<\/p>\n
\u95ee\u98981\uff1a\u5982\u679c\u5728\u67d0\u4e2a\u5ba2\u6237\u7aef\u83b7\u5f97\u9501\u540e\uff0credis\u4e3b\u670d\u52a1\u5668\u5b95\u673a\u4e86\uff0c\u90a3\u4e48\u5373\u4f7f\u6211\u4eec\u4f7f\u7528\u4e86\u4e3b\u4ece\u5907\u4efd\uff0c\u4ece\u5c5e\u670d\u52a1\u5668\u88ab\u63d0\u5347\u4e3a\u4e3b\u670d\u52a1\u5668\uff0c\u56e0\u4e3aredis\u5907\u4efd\u662f\u5f02\u6b65\u7684\u539f\u56e0\uff0c\u8fd9\u91cc\u7684\u9501\u662f\u6ca1\u6cd5\u53ca\u65f6\u540c\u6b65\u5230\u4ece\u5c5e\u670d\u52a1\u5668\u7684\u3002<\/p>\n
\u95ee\u98982\uff1a\u5982\u679c\u4e00\u4e2a\u5ba2\u6237\u7aef\u5728\u83b7\u5f97\u9501\u540e\uff0c\u6267\u884c\u7684\u64cd\u4f5c\u8d85\u8fc7\u4e86\u9501\u7684\u6709\u6548\u671f\uff0c\u9501\u88ab\u81ea\u52a8\u91ca\u653e\u4e86\u3002\u90a3\u4e48\u540e\u7eed\u7684\u64cd\u4f5c\u662f\u6ca1\u6cd5\u53d7\u5230\u9501\u7684\u4fdd\u62a4\u7684\u3002<\/p>\n
\u95ee\u98982\u7684\u89e3\u51b3\u65b9\u6848\u53ef\u4ee5\u662fwatch\uff0c\u5728\u83b7\u53d6\u9501\u540e\uff0c\u53ef\u4ee5\u7acb\u523bwatch\u8d44\u6e90\uff0c\u7136\u540e\u518d\u6267\u884c\u4f59\u4e0b\u64cd\u4f5c\u3002<\/p>\n
\u95ee\u98981\u7684\u89e3\u51b3\u65b9\u6848\u5219\u662f\u63a5\u4e0b\u6765\u8981\u4ecb\u7ecd\u7684redlock\u7b97\u6cd5<\/p>\n
3.redlock<\/h2>\n
redlock\u7b97\u6cd5\u662fRedis\u7684\u4f5c\u8005antirez\u63d0\u51fa\u6765\u7684\u3002
\n\u53ef\u4ee5\u88ab\u6982\u8ff0\u4e3a\u4ee5\u4e0b\u51e0\u4e2a\u6b65\u9aa4\uff1a<\/p>\n
\n- 1.\u83b7\u53d6\u5f53\u524d\u65f6\u95f4\uff08\u6beb\u79d2\u6570\uff09:start_time\u3002<\/p>\n<\/li>\n
- \n
2.\u6309\u987a\u5e8f\u83b7\u5f97N\u4e2aRedis\u8282\u70b9\u7684\u9501\uff08\u4f7f\u7528\u76f8\u540c\u7684key\u548cidentifier\uff0c\u5e76\u8bbe\u7f6e\u521d\u59cb\u6709\u6548\u65f6\u95f4:init_validity_time\uff09\u3002\u5728\u83b7\u5f97\u6bcf\u4e2aredis\u7ed3\u70b9\u7684\u9501\u7684\u65f6\u5019\uff0c\u90fd\u8981\u8bbe\u7f6e\u4e00\u4e2atimeout\u53c2\u6570\uff0c\u8fd9\u4e2atimeout\u8981\u8fdc\u5c0f\u4e8e\u9501\u7684\u81ea\u52a8\u91ca\u653e\u65f6\u95f4\u3002\u4f8b\u5982\uff1a\u5982\u679c\u9501\u7684\u81ea\u52a8\u91ca\u653e\u65f6\u95f4\u662f10s\uff0ctimeout\u5e94\u8be5\u4e3a~5-55ms\uff08\u8fd8\u5f97\u89c6\u7f51\u7edc\u60c5\u51b5\u51b3\u5b9a\uff09\u3002\u8fd9\u6837\u53ef\u4ee5\u9632\u6b62\u5728\u83b7\u53d6\u9501\u65f6\uff0c\u8282\u70b9\u5b95\u673a\uff0c\u5bfc\u81f4\u8017\u65f6\u8fc7\u957f\u9501\u88ab\u91ca\u653e\u4e86\u3002\u5982\u679c\u83b7\u53d6\u9501\u5931\u8d25\u5219\u7acb\u523b\u83b7\u53d6\u4e0b\u4e00\u4e2aredis\u8282\u70b9\u7684\u9501<\/p>\n<\/li>\n
- \n
3.client\u8ba1\u7b97\u4e3a\u4e86\u83b7\u53d6\u9501\u82b1\u4e86\u591a\u957f\u65f6\u95f4\uff1aused_time = current_time – start_time\u3002\u5f53\u4e14\u4ec5\u5f53client\u53ef\u4ee5\u83b7\u53d6\u5927\u591a\u6570\u5b9e\u4f8b\u7684\u65f6\u5019\uff08\u81f3\u5c11N \/ 2 + 1\u4e2a)\uff0c\u6240\u82b1\u8d39\u7684\u65f6\u95f4\u5c0f\u4e8e\u9501\u7684\u6709\u6548\u65f6\u95f4\uff0c\u624d\u8ba4\u4e3a\u83b7\u5f97\u4e86\u9501\u3002<\/p>\n<\/li>\n
- \n
4.\u5982\u679c\u83b7\u5f97\u4e86\u9501\uff0c\u91cd\u65b0\u8ba1\u7b97\u9501\u7684\u6709\u6548\u65f6\u95f4:validity_time = init_validity_time – used_time<\/p>\n<\/li>\n
- \n
5.\u5982\u679c\u9501\u83b7\u53d6\u5931\u8d25(\u65e0\u6cd5\u83b7\u53d6N\/2 + 1\u4e2a\u8282\u70b9\u7684\u9501\uff0c\u6216\u8005\u6709\u6548\u65f6\u95f4validity_time\u662f\u8d1f\u6570\uff09\uff0c\u5219\u91ca\u653e\u6240\u6709\u5b9e\u4f8b\u7684\u9501\uff08\u5373\u4f7f\u83b7\u5f97\u9501\u7684\u65f6\u5019\u5931\u8d25\u4e86\uff0c\u8fd9\u4e3b\u8981\u662f\u8003\u8651\u5230\u6709\u7684\u65f6\u5019\u9501\u83b7\u5f97\u6210\u529f\u4e86\uff0c\u4f46\u662f\u544a\u77e5\u5ba2\u6237\u7aef\u65f6\u7f51\u7edc\u5f02\u5e38\uff09\u3002<\/p>\n<\/li>\n<\/ul>\n
\u8fd9\u5f88\u597d\u7684\u89e3\u51b3\u4e86\u4e0a\u8ff0\u7684\u95ee\u98981\uff0c\u901a\u8fc7\u591a\u4e2aredis\u8282\u70b9\u4e86\u6765\u4fdd\u8bc1\u5206\u5e03\u5f0f\u9501\u670d\u52a1\u7684\u53ef\u9760\u6027\u3002<\/p>\n
\u53c2\u8003\u6587\u7ae0<\/h2>\n
Distributed locks with Redis<\/a><\/p>\n\u57fa\u4e8eRedis\u7684\u5206\u5e03\u5f0f\u9501\u5230\u5e95\u5b89\u5168\u5417\uff08\u4e0a\uff09\uff1f<\/a><\/p>\n\u57fa\u4e8eRedis\u7684\u5206\u5e03\u5f0f\u9501\u5230\u5e95\u5b89\u5168\u5417\uff08\u4e0b\uff09\uff1f<\/a><\/p>\nredis\u4e8b\u52a1<\/a><\/p>\n6.2.3 Building a lock in Redis<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"