我已經到位以下蒙戈測試集羣MongoDB的慢查詢性能
- 沒有碎片-2
- 沒有配置服務器-1
- mongos實例-2
- 複製的未啓用
我有大約4100萬條記錄在整個碎片中分割,我定義了一個複合索引{field1:1,field2:1,field3:1},我的查詢是(x和y之間的字段= 1和字段2),我預計複合索引對於這些查詢很有用,但查詢響應時間大約爲8秒,對於我描述的查詢。當我執行查找時,我只指定了感興趣的字段。
Mongos安裝在執行查詢的機器上,我使用java來執行查詢。
有人可以拋出一些可能的原因,爲什麼這個查詢需要這麼長的時間?如果需要,我很樂意提供更多信息。
以下是輸出解釋命令
{
"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
}
在我的分貝的樣品文件是如下
{
"_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"
}
有在上述文檔一些其它字段我不能暴露外,但它的字符串和字符串的簡單鍵值
這是我如何查詢數據庫
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。感謝任何幫助。
請運行'你的查詢explain'和結果添加到您的文章 –
看來,查詢計劃會掃描索引LOGIN_ID每個值,共有將近180萬登錄記錄。你可以添加你的查詢和一個示例文檔。另外,您使用的是哪個版本的MongoDB? –
此查詢返回多少個文檔?如果它提取的文檔太多,請嘗試'limit' –