MongoDB生成测试数据脚本
for (var i = 1; i <= 9000000; i++) {
db.testData.insert( { x : i , name: "MACLEAN" , name1:"MACLEAN", name2:"MACLEAN", name3:"MACLEAN"} )
}
db.testData.find().count();
x小于0
db.testData.find({x: {$lt : 0}});
x大于400
db.testData.find({x: {$gt : 400}});
> db.testData.find({x: {$gt : 400}}).explain();
{
"cursor" : "BasicCursor",
"isMultiKey" : false,
"n" : 5860637,
"nscannedObjects" : 5861039,
"nscanned" : 5861039,
"nscannedObjectsAllPlans" : 5861039,
"nscannedAllPlans" : 5861039,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 45789,
"nChunkSkips" : 0,
"millis" : 2598,
"server" : "macleandeMacBook-Pro.local:27017",
"filterSet" : false
}
>
>
>
>
> db.testData.ensureIndex({x:1});
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
>
>
>
>
> db.testData.find({x: {$gt : 400}}).explain();
{
"cursor" : "BtreeCursor x_1",
"isMultiKey" : false,
"n" : 5860637,
"nscannedObjects" : 5860637,
"nscanned" : 5860637,
"nscannedObjectsAllPlans" : 5860637,
"nscannedAllPlans" : 5860637,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 45786,
"nChunkSkips" : 0,
"millis" : 6165,
"indexBounds" : {
"x" : [
[
400,
Infinity
]
]
},
"server" : "macleandeMacBook-Pro.local:27017",
"filterSet" : false
}
> db.testData.find({x: {$lt : 0}}).explain();
{
"cursor" : "BtreeCursor x_1",
"isMultiKey" : false,
"n" : 0,
"nscannedObjects" : 0,
"nscanned" : 0,
"nscannedObjectsAllPlans" : 0,
"nscannedAllPlans" : 0,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 0,
"indexBounds" : {
"x" : [
[
-Infinity,
0
]
]
},
"server" : "macleandeMacBook-Pro.local:27017",
"filterSet" : false
}
> db.testData.find({x: {$lt : 0}}).explain();
{
"cursor" : "BtreeCursor x_1",
"isMultiKey" : false,
"n" : 0,
"nscannedObjects" : 0,
"nscanned" : 0,
"nscannedObjectsAllPlans" : 0,
"nscannedAllPlans" : 0,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 0,
"indexBounds" : {
"x" : [
[
-Infinity,
0
]
]
},
"server" : "macleandeMacBook-Pro.local:27017",
"filterSet" : false
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