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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