Mongodb:高获取数据库锁

Question

我遇到了与MongoDb性能相关的问题.查询是几十秒,通过命令db.currentOp()我可以看到,我的所有查询都在等待数据库锁定.例如:

只是简单的查询

"desc" : "conn36316",
"threadId" : "7420",
"connectionId" : 36316,
"client" : "127.0.0.1:34538",
"active" : true,
"opid" : 197242270,
"secs_running" : 190,
"microsecs_running" : NumberLong(190574655),
"op" : "query",
"ns" : "db.items",
"query" : {
    "find" : "items",
    "filter" : {
        "$msg" : "query not recording (too large)"
    }
},
"numYields" : 92,
"locks" : {
    "Global" : "r",
    "Database" : "r"
},
"waitingForLock" : true,
"lockStats" : {
    "Global" : {
        "acquireCount" : {
            "r" : NumberLong(186)
        },
        "acquireWaitCount" : {
            "r" : NumberLong(1)
        },
        "timeAcquiringMicros" : {
            "r" : NumberLong(24392)
        }
    },
    "Database" : {
        "acquireCount" : {
            "r" : NumberLong(93)
        },
        "acquireWaitCount" : {
            "r" : NumberLong(53)
        },
        "timeAcquiringMicros" : {
            "r" : NumberLong(60099891)
        }
    },
    "Collection" : {
        "acquireCount" : {
            "r" : NumberLong(92)
        }
    }
}

构建索引查询

 "desc" : "TTLMonitor",
 "threadId" : "12592",
 "active" : true,
 "opid" : 958,
 "op" : "none",
 "ns" : "",
 "query" : {

 },
 "numYields" : 0,
 "locks" : {
         "Global" : "r",
         "Database" : "r"
 },
 "waitingForLock" : true,
 "lockStats" : {
         "Global" : {
                 "acquireCount" : {
                         "r" : NumberLong(4)
                 }
         },
         "Database" : {
                 "acquireCount" : {
                         "r" : NumberLong(2)
                 },
                 "acquireWaitCount" : {
                         "r" : NumberLong(1)
                 },
                 "timeAcquiringMicros" : {
                         "r" : NumberLong("3571165481")
                 }
         },
         "Collection" : {
                 "acquireCount" : {
                         "r" : NumberLong(3)
                 }
         }
 }

正如您所看到的,等待获取锁定需要花费大量时间.对于常见查询,它等于60秒,对于索引,它等于3571秒.

我的工作计算机可以更快地创建类似的索引,它可以在服务器上创建.

我的服务器是具有10个内核的虚拟机,40GB的内存和磁盘是raid1阵列.

我正在使用MongoDb版本3.2.6(WiredTiger).

可能是什么问题呢？我该如何诊断问题？

Answer 1

我的问题是磁盘子系统速度慢，根据官方文档更换ssd解决了问题