我使用的是 MongoDB 版本 2.4.8。
[test] 2014-03-25 14:42:13.0 >>> db.users.getIndexes();
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "test.users",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"username" : 1,
"age" : 1
},
"ns" : "test.users",
"name" : "username_1_age_1"
},
{
"v" : 1,
"key" : {
"age" : 1,
"username" : 1
},
"ns" : "test.users",
"name" : "age_1_username_1"
}
]
[test] 2014-03-25 14:44:36.550 >>>
[test] 2014-03-25 14:33:12.945 >>> db.users.find({"age" : 14, "username" : /.*/}).explain()
{
"cursor" : "BtreeCursor age_1_username_1 multi",
"isMultiKey" : false,
"n" : 16850,
"nscannedObjects" : 16850,
"nscanned" : 16850,
"nscannedObjectsAllPlans" : 16850,
"nscannedAllPlans" : 16850,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 86,
"indexBounds" : {
"age" : [
[
14,
14
]
],
"username" : [
[
"",
{
}
],
[
/.*/,
/.*/
]
]
},
"server" : "server01:27017"
}
解释输出的含义是什么username
part?
"username" : [
[
"",
{
}
],
[
/.*/,
/.*/
]
]
我很难理解这部分 否
无论我以正式还是非正式的方式看待它,这都很重要。