我有一个如下查询。显然更好的索引是“platform_1_keyuserAccountID_1_weiboAccountID_1_postTime_1”,但是 mongodb 选择“weiboAccountID_1”,我做错了吗?
db.inbox_weibo.find({platform: "sina", keyuserAccountID:"1665337047", weiboAccountID: "2271338624"}).explain(true);
{ "cursor" : "BtreeCursor weiboAccountID_1", “isMultiKey”:假, “n”:1, “nscannedObjects”:1, “nscanned”:1, “nscannedObjectsAllPlans”:24, “nscannedAllPlans”:634425, “scanAndOrder”:假, “indexOnly”:假, “nYields”:1, “nChunkSkips”:0, “毫”:2912, “索引边界”:{ “微博账号”:[ [ "2271338624", “2271338624” ] ] }, “所有计划”:[ { "cursor" : "BtreeCursor weiboAccountID_1", “isMultiKey”:假, “n”:1, “nscannedObjects”:1, “nscanned”:1, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “微博账号”:[ [ "2271338624", “2271338624” ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_dealed_1_operatorID_1_weiboAccountID_1_postTIme_-1", “isMultiKey”:假, “n”:1, “nscannedObjects”:1, “nscanned”:62, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “操作员ID”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “微博账号”:[ [ "2271338624", “2271338624” ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_weiboAccountID_1_postTime_-1", “isMultiKey”:假, “n”:1, “nscannedObjects”:1, “nscanned”:1, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “微博账号”:[ [ "2271338624", “2271338624” ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }, { "cursor" : "BtreeCursor platform_keyuserAccountID_dealed_postTime_weiboAccountID", “isMultiKey”:假, “n”:1, “nscannedObjects”:1, “nscanned”:634331, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “微博账号”:[ [ "2271338624", “2271338624” ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_mid_1", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “中” : [ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_dealerID_1", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “经销商ID”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ] } }, { "cursor" : "BtreeCursor distinctAccountAgg", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “操作员ID”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }, { "cursor" : "BtreeCursor fanCountUndealed", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “来自类型”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “粉丝数”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “使用图片”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ] } }, { "cursor" : "BtreeCursor retweetCountUndealed", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “来自类型”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “sourceRetweetCount”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “使用图片”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ] } }, { "cursor" : "BtreeCursor interactUndealed", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “来自类型”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “用户交互计数”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ], “使用图片”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_dealed_1_dealTime_-1", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “交易时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_dealerID_1_postTime_-1", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “经销商ID”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }, { "cursor" : "BtreeCursor platform_1_keyuserAccountID_1_postTime_-1", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “平台” : [ [ “新浪”, “新浪” ] ], “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “后时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }, { "cursor" : "BtreeCursor keyuserAccountID_dealed_createTime_-1", “isMultiKey”:假, “n”:0, “nscannedObjects”:2, “nscanned”:3, “scanAndOrder”:假, “indexOnly”:假, “nChunkSkips”:0, “索引边界”:{ “keyuserAccountID”:[ [ "1665337047", “1665337047” ] ], “成交”:[ [ { “$minElement”:1 }, { “$ 最大元素”:1 } ] ], “创建时间”:[ [ { “$ 最大元素”:1 }, { “$minElement”:1 } ] ] } }