mongodb find上的性能非常慢

Question

我是nodejs和mongodb的新手。 為了進行測試，我從#oscars中捕獲了2.500.000條推文。 現在，我正在處理數據，但是下面的查詢非常慢……（最多40秒）（我直接在控制台上進行查詢）

db.oscars.find({user.screen_name: "monxas"})

難道我做錯了什么？ 無論如何有加速這個查詢？

推文具有這種結構，如果有幫助的話：

 {
  "_id" : ObjectId("54ea1f0f5fbae7a02067024b"),
  "created_at" : "Sun Feb 22 18:25:20 +0000 2015",
  "id" : 5.6956360590721434E+17,
  "id_str" : "569563605907214338",
  "text" : "#Oscars2015 Who will win tonight? All hopes are on you guys.",
  "source" : "<a href=\"http://twitter.com/#!/download/ipad\" rel=\"nofollow\">Twitter for iPad</a>",
  "truncated" : false,
  "in_reply_to_status_id" : null,
  "in_reply_to_status_id_str" : null,
  "in_reply_to_user_id" : null,
  "in_reply_to_user_id_str" : null,
  "in_reply_to_screen_name" : null,
  "user" : {
    "id" : 2596742425.0,
    "id_str" : "2596742425",
    "name" : "jclivesforever26",
    "screen_name" : "jacuasay092600",
    "location" : "",
    "url" : null,
    "description" : "Da Bulls!!! Ed Sheeran is life!!!",
    "protected" : false,
    "verified" : false,
    "followers_count" : 21,
    "friends_count" : 183,
    "listed_count" : 0,
    "favourites_count" : 78,
    "statuses_count" : 283,
    "created_at" : "Mon Jun 30 18:13:13 +0000 2014",
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    "geo_enabled" : true,
    "lang" : "en",
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    "profile_background_color" : "C0DEED",
    "profile_background_image_url" : "http://abs.twimg.com/images/themes/theme1/bg.png",
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    "profile_link_color" : "0084B4",
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  "entities" : {
    "hashtags" : [{
        "text" : "Oscars2015",
        "indices" : [0, 11]
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}

Answer 1

使用explain游標方法查找有關查詢計划的更多信息

db.oscars.find({user.screen_name: "monxas"}).explain();

如果沒有定義索引，則可以在user.screen_name上添加一個user.screen_name以使用ensureIndex加快查詢速度，如下所示

db.oscars.ensureIndex({"user.screen_name": 1});