我已经到位以下蒙戈测试集群MongoDB的慢查询性能
- 没有碎片-2
- 没有配置服务器-1
- mongos实例-2
- 复制的未启用
我有大约4100万条记录在整个碎片中分割,我定义了一个复合索引{field1:1,field2:1,field3:1},我的查询是(x和y之间的字段= 1和字段2),我预计复合索引对于这些查询很有用,但查询响应时间大约为8秒,对于我描述的查询。当我执行查找时,我只指定了感兴趣的字段。
Mongos安装在执行查询的机器上,我使用java来执行查询。
有人可以抛出一些可能的原因,为什么这个查询需要这么长的时间?如果需要,我很乐意提供更多信息。
以下是输出解释命令
{
"indexBounds": {
"LOGIN_ID": [
[
{
"$minElement": 1
},
{
"$maxElement": 1
}
]
],
"LOGIN_TIME": [
[
1262332800000,
1293782400000
]
]
},
"nYields": 7,
"millisShardTotal": 7410,
"millisShardAvg": 7410,
"numQueries": 1,
"nChunkSkips": 0,
"shards": {
"server1:27017": [
{
"nYields": 7,
"nscannedAllPlans": 1769804,
"allPlans": [
{
"cursor": "BtreeCursor LOGIN_TIME_1_LOGIN_ID_1",
"indexBounds": {
"LOGIN_ID": [
[
{
"$minElement": 1
},
{
"$maxElement": 1
}
]
],
"LOGIN_TIME": [
[
1262332800000,
1293782400000
]
]
},
"nscannedObjects": 1763903,
"nscanned": 1763903,
"n": 14081
},
{
"cursor": "BasicCursor",
"indexBounds": {},
"nscannedObjects": 5901,
"nscanned": 5901,
"n": 0
}
],
"millis": 7410,
"nChunkSkips": 0,
"server": "server2:27017",
"n": 14081,
"cursor": "BtreeCursor LOGIN_TIME_1_LOGIN_ID_1",
"oldPlan": {
"cursor": "BtreeCursor LOGIN_TIME_1_LOGIN_ID_1",
"indexBounds": {
"LOGIN_ID": [
[
{
"$minElement": 1
},
{
"$maxElement": 1
}
]
],
"LOGIN_TIME": [
[
1262332800000,
1293782400000
]
]
}
},
"scanAndOrder": false,
"indexBounds": {
"LOGIN_ID": [
[
{
"$minElement": 1
},
{
"$maxElement": 1
}
]
],
"LOGIN_TIME": [
[
1262332800000,
1293782400000
]
]
},
"nscannedObjectsAllPlans": 1769804,
"isMultiKey": false,
"indexOnly": false,
"nscanned": 1763903,
"nscannedObjects": 1763903
}
]
},
"n": 14081,
"cursor": "BtreeCursor LOGIN_TIME_1_LOGIN_ID_1",
"oldPlan": {
"cursor": "BtreeCursor LOGIN_TIME_1_LOGIN_ID_1",
"indexBounds": {
"LOGIN_ID": [
[
{
"$minElement": 1
},
{
"$maxElement": 1
}
]
],
"LOGIN_TIME": [
[
1262332800000,
1293782400000
]
]
}
},
"numShards": 1,
"clusteredType": "ParallelSort",
"nscannedAllPlans": 1769804,
"nscannedObjectsAllPlans": 1769804,
"millis": 7438,
"nscanned": 1763903,
"nscannedObjects": 1763903
}
在我的分贝的样品文件是如下
{
"_id" : ObjectId("52d5192c1a45f84e48c24e2f"),
"LOGIN_ID" : <loginId>,
"LOGIN_TIME" : NumberLong("1372343932000"),
"BUSINESS_ID" : <businessId>,
"USER_ID" : <userid>,
"EMAIL" : "[email protected]",
"SITE_POD_NAME" : "x",
"USER_AGENT" : "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.31 (KHTML. like Gecko) Chrome/26.0.1410.43 Safari/537.31"
}
有在上述文档一些其它字段我不能暴露外,但它的字符串和字符串的简单键值
这是我如何查询数据库
DBObject dbObject = new BasicDBObject("BUSINESS_ID", businessId)
.append("LOGIN_TIME",
new BasicDBObject("$gte",start).append("$lt", end))
.append("LOGIN_TYPE", loginType);
long startTime = System.currentTimeMillis();
DBObject keys = new BasicDBObject("LOGIN_TIME", 1);
DBCursor find = collection.find(dbObject, keys);
int count = 0;
while (find.hasNext()) {
find.next();
count++;
}
long endTime = System.currentTimeMillis();
Mongo DB版本是2.4.9。感谢任何帮助。
请运行'你的查询explain'和结果添加到您的文章 –
看来,查询计划会扫描索引LOGIN_ID每个值,共有将近180万登录记录。你可以添加你的查询和一个示例文档。另外,您使用的是哪个版本的MongoDB? –
此查询返回多少个文档?如果它提取的文档太多,请尝试'limit' –