{"id":315,"date":"2012-03-16T20:45:13","date_gmt":"2012-03-16T12:45:13","guid":{"rendered":"http:\/\/www.royalwzy.com\/?p=315"},"modified":"2014-01-16T20:55:08","modified_gmt":"2014-01-16T12:55:08","slug":"mongodb%e5%ad%a6%e4%b9%a004-%e6%80%a7%e8%83%bd%e5%88%86%e6%9e%90%e5%8f%8a%e7%b4%a2%e5%bc%95%e6%93%8d%e4%bd%9c","status":"publish","type":"post","link":"http:\/\/www.royalwzy.com\/?p=315","title":{"rendered":"MongoDB\u5b66\u4e6004–\u6027\u80fd\u5206\u6790\u53ca\u7d22\u5f15\u64cd\u4f5c"},"content":{"rendered":"
MongoDB\u4e2d\u7684\u6027\u80fd\u5206\u6790\u53ca\u7d22\u5f15\u64cd\u4f5c<\/p>\n
\n
    \n
  1. \u6027\u80fd\u5206\u6790\u51fd\u6570explain();\n
      \n
    1. \u8bed\u6cd5:cursor.explain(verbose),verbose\u4e3atrue\u6216\u80051\u7684\u65f6\u5019\u4f1a\u8f93\u51fa\u6240\u6709\u7684\u6267\u884c\u8ba1\u5212\u548c\u65e7\u7684\u6267\u884c\u8ba1\u5212;<\/li>\n
    2. \u4e00\u822c\u662f\u8ddf\u5728find()\u64cd\u4f5c\u540e\u4f7f\u7528(eg:db.mycoll.find().explain()),\u5b83\u7684\u6267\u884c\u901f\u5ea6\u51b3\u5b9a\u4e8e\u5b9e\u9645\u67e5\u8be2\u7684\u901f\u5ea6,\u5c3d\u7ba1explain()\u4f1a\u989d\u5916\u751f\u6210\u4e00\u7cfb\u5217\u5019\u9009\u7684\u6267\u884c\u8ba1\u5212,\u4f46\u662f\u8ddf\u5b9e\u9645\u67e5\u8be2\u7684\u6027\u80fd\u76f8\u5dee\u4e0d\u5927;<\/li>\n
    3. explain\u51fd\u6570\u7684\u8f93\u51fa\u7ed3\u679c; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"\"<\/li>\n
    4. explain()\u51fd\u6570\u8f93\u51fa\u7ed3\u679c\u542b\u4e49:\n
        \n
      1. cursor:\u67e5\u627e\u4f7f\u7528\u7684cursor\u7c7b\u578b\u548c\u7d22\u5f15\u540d\u79f0;<\/li>\n
      2. isMultiKey:\u662f\u5426\u662f\u8054\u5408\u7d22\u5f15;<\/li>\n
      3. n:\u8fd4\u56de\u8bb0\u5f55\u7684\u4e2a\u6570;<\/a><\/li>\n
      4. nscannedObjects:\u904d\u5386\u7684\u6587\u6863\u5bf9\u8c61\u7684\u4e2a\u6570;<\/li>\n
      5. nscanned:\u904d\u5386\u7684\u6587\u6863\u7684\u4e2a\u6570;<\/li>\n
      6. nscannedObjectsAllPlans: <num>;<\/li>\n
      7. nscannedAllPlans: <num>;<\/li>\n
      8. scanAndOrder: <boolean>;<\/li>\n
      9. indexOnly: <boolean>;<\/li>\n
      10. nYields: <num>;<\/li>\n
      11. nChunkSkips: <num>;<\/li>\n
      12. millis:\u6d88\u8017\u7684\u65f6\u95f4,\u5355\u4f4d\u662fms;<\/li>\n
      13. indexBounds:\u7d22\u5f15\u7684\u8303\u56f4,\u5982\u679c\u4e3a\u7a7a\u8868\u793a\u6ca1\u6709\u7528\u5230\u7d22\u5f15;<\/li>\n
      14. llPlans:\u4ea7\u751f\u7684\u6240\u6709\u7684\u5019\u9009\u7684\u6267\u884c\u8ba1\u5212;<\/li>\n
      15. oldPlan:\u65e7\u7684\u6267\u884c\u8ba1\u5212;<\/li>\n
      16. server:\u4e3b\u673a\u540d\u548c\u7aef\u53e3\u53f7<host:port>;<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/li>\n
      17. \u521b\u5efa\/\u5220\u9664\u7d22\u5f15,\u53ca\u524d\u540e\u6548\u7387\u7684\u5bf9\u6bd4;\n
          \n
        1. \u521b\u5efa\u7d22\u5f15\u8bed\u6cd5:db.mycoll.ensureIndex(keypattern[,options]);\n
            \n
          1. keypattern:\u662f\u7d22\u5f15\u7684\u952e;<\/li>\n
          2. options:\u53ef\u4ee5\u53d6name,unique,dropDups,sparse\u7b49\u503c;<\/li>\n
          3. \u53ea\u6709\u5728\u67d0\u4e2a\u5217\u4e0a\u6ca1\u6709\u7d22\u5f15\u624d\u4f1a\u521b\u5efa,\u5982\u679c\u5b58\u5728\u7d22\u5f15\u7684\u8bdd\u5c31\u4e0d\u518d\u521b\u5efa;<\/li>\n
          4. \u9ed8\u8ba4\u521b\u5efa\u7684\u662fb-tree\u7d22\u5f15;<\/li>\n
          5. \u53ef\u4ee5\u5728\u5b50\u6587\u6863\u4e0a\u521b\u5efa\u7d22\u5f15:db.mycoll.ensureIndex({“object.attritude”:1});<\/li>\n<\/ol>\n<\/li>\n
          6. \u6ca1\u6709\u521b\u5efa\u7d22\u5f15\u65f6,\u67e5\u627ename=index10000\u7684\u6548\u7387:db.index.find({“name”:”index10000″}).explain();\u4f7f\u7528\u7684\u662fBasicCursor\u5373\u6ca1\u6709\u7d22\u5f15,\u626b\u63cf\u4e8610w\u6761\u8bb0\u5f55\u540e\u8fd4\u56de1\u6761\u8bb0\u5f55,\u6d88\u8017\u4e86192ms; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"\"<\/li>\n
          7. \u5728name\u5217\u521b\u5efa\u4e00\u4e2a\u540d\u4e3aidx_index_name\u7684\u7d22\u5f15:db.index.ensureIndex({name:1}, {name:”idx_index_name”}),\u5982\u679c\u4e0d\u6307\u5b9a\u7b2c\u4e8c\u4e2a\u53c2\u6570\u4e2d\u7684name\u7684\u8bdd,\u5219\u7cfb\u7edf\u4f1a\u81ea\u52a8\u751f\u6210\u4e00\u4e2a\u7d22\u5f15\u7684\u540d\u79f0; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"\"<\/li>\n
          8. \u67e5\u770b\u521b\u5efa\u7d22\u5f15\u540e\u7684\u6548\u7387,\u53d1\u73b0\u4f7f\u7528\u4e86Btree\u7d22\u5f15,\u4e00\u5171\u626b\u63cf\u4e00\u6761\u8bb0\u5f55,\u8fd4\u56de1\u6761\u8bb0\u5f55,\u5e76\u4e14\u77ac\u95f4\u8fd4\u56de; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"\"<\/li>\n
          9. \u5220\u9664\u7d22\u5f15\u8bed\u6cd5:db.mycoll.dropIndex(index),\u53ef\u4ee5\u6839\u636e\u540d\u79f0\u5220\u9664\u7d22\u5f15,\u6216\u8005\u6839\u636e\u521b\u5efa\u65f6\u6307\u5b9a\u7684\u952e\u503c;\n
              \n
            1. db.mycoll.dropIndex(“indexName”):\u6839\u636e\u7d22\u5f15\u540d\u79f0\u5220\u9664;<\/li>\n
            2. db.mycoll.dropIndex({ “indexKey” : 1 }):\u6839\u636ekey\u503c\u5220\u9664\u7d22\u5f15;<\/li>\n
            3. \u5982\u679c\u8981\u5220\u9664\u67d0\u4e2a\u96c6\u5408\u4e0b\u6240\u6709\u7684\u7d22\u5f15,\u5219\u4f7f\u7528db.mycoll.dropIndexes(),\u4f46\u662f\u65e0\u6cd5\u5220\u9664\u7cfb\u7edf\u81ea\u52a8\u521b\u5efa\u7684\u57fa\u4e8e_id\u5217\u7684\u7d22\u5f15,\u5b83\u7531\u6570\u636e\u5e93\u81ea\u5df1\u7ef4\u62a4;<\/li>\n<\/ol>\n<\/li>\n
            4. \u91cd\u5efa\u7d22\u5f15:db.mycoll.reIndex(),\u662f\u628a\u539f\u6765\u7684\u7d22\u5f15\u5220\u6389\u540e\u91cd\u5efa; \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\"\"<\/li>\n<\/ol>\n<\/li>\n
            5. \u552f\u4e00\u7d22\u5f15:\n
                \n
              1. \u8bed\u6cd5:db.mycoll.ensureIndex(keypattern, {unique:true});<\/li>\n
              2. \u521b\u5efa\u4e00\u4e2a\u57fa\u4e8ename\u5217\u7684\u552f\u4e00\u7d22\u5f15unq_index_name:db.index.ensureIndex({name:1}, {name:”unq_index_name”, unique:true});\"\"<\/li>\n
              3. \u5982\u679c\u67d0\u4e00\u4e2a\u5217\u4e0a\u5df2\u7ecf\u5b58\u5728\u7684\u91cd\u590d\u503c,\u5728\u8fd9\u6837\u7684\u5217\u4e0a\u521b\u5efa\u552f\u4e00\u7d22\u5f15\u7684\u8bdd\u53ef\u4ee5\u4f7f\u7528dropDups\u9009\u9879,\u8fd9\u6837\u7cfb\u7edf\u4f1a\u4fdd\u7559\u7b2c\u4e00\u6761\u8bb0\u5f55,\u5220\u9664\u5269\u4e0b\u91cd\u590d\u7684\u8bb0\u5f55:db.mycoll.ensureIndex(keypattern, {unique:true, dropDups:true});<\/li>\n
              4. \u5982\u679c\u67d0\u4e00\u4e2a\u5217\u662f\u552f\u4e00\u5217,\u63d2\u5165\u6570\u636e\u65f6\u6ca1\u6709\u63d2\u5165\u6b64\u5217\u7684\u8bdd\u4f1a\u4fdd\u5b58\u4e00\u4e2anull\u503c,\u4e00\u4e2a\u552f\u4e00\u5217\u4e2d\u53ea\u80fd\u6709\u4e00\u4e2anull\u503c;(\u8fd9\u70b9\u4e0e\u5173\u7cfb\u578b\u6570\u636e\u5e93\u4e0d\u540c,\u5173\u7cfb\u578b\u6570\u636e\u5e93\u4e2d\u552f\u4e00\u5217\u4e2d\u53ef\u4ee5\u4fdd\u5b58null\u503c,\u4f46\u662f\u5728mongodb\u4e2dnull\u503c\u4f5c\u4e3a\u4e86\u4e00\u4e2a\u503c\u6765\u6bd4\u8f83)<\/li>\n<\/ol>\n<\/li>\n
              5. \u7ec4\u5408\u7d22\u5f15:\n
                  \n
                1. \u8bed\u6cd5\u4e0e\u666e\u901a\u7d22\u5f15\u76f8\u540c,\u53ea\u662f\u9700\u8981\u591a\u6307\u5b9a\u51e0\u4e2a\u5217:db.mycoll.ensureIndex({key1:value1, key2:value2, …});<\/li>\n
                2. \u952e\u540e\u9762\u7684\u6570\u5b57\u8868\u793a\u7d22\u5f15\u7684\u5b58\u50a8\u987a\u5e8f,\u5176\u4e2d1\u8868\u793a\u5347\u5e8f,-1\u8868\u793a\u964d\u5e8f.\u5728\u968f\u673a\u8bbf\u95ee\u7684\u65f6\u5019\u610f\u4e49\u4e0d\u5927,\u4f46\u662f\u5728\u6392\u5e8f\u6216\u8005\u662f\u8303\u56f4\u67e5\u8be2\u65f6\u5f88\u91cd\u8981;<\/li>\n
                3. \u5982\u679c\u5728a,b,c\u4e09\u5217\u4e0a\u521b\u5efa\u4e86\u8fd9\u7d22\u5f15,\u5219\u4ee5a,ab,abc\u5f00\u5934\u7684\u6761\u4ef6\u90fd\u53ef\u4ee5\u4f7f\u7528\u5230\u6b64\u7d22\u5f15;<\/li>\n<\/ol>\n<\/li>\n
                4. \u7a00\u758f\u7d22\u5f15:\n
                    \n
                  1. Sparse indexes only contain entries for documents that have the indexes field, any document that is missing the field is not indexes;<\/li>\n
                  2. By contrast, non-sparse indexes contrain all documents in collection, and store null values for documents that do not contrain the indexes field;<\/li>\n
                  3. \u8bed\u6cd5:db.mycoll.ensureIndex(keypattern, {sparse:true});<\/li>\n
                  4. \u7a00\u758f\u7d22\u5f15\u4e0e\u975e\u7a00\u758f\u7d22\u5f15\u7684\u5bf9\u6bd4;<\/li>\n<\/ol>\n<\/li>\n
                  5. hint:\n
                      \n
                    1. \u67e5\u8be2\u4f18\u5316\u5668\u4f1a\u9009\u62e9\u6700\u4f18\u7684\u6267\u884c\u8ba1\u5212,\u800c\u4e14\u7b2c\u4e00\u6b21\u6267\u884c\u540e\u7684\u6267\u884c\u8ba1\u5212\u5c06\u4f1a\u88ab\u4fdd\u5b58;\u5982\u679c\u9700\u8981\u4f7f\u7528\u81ea\u5df1\u6307\u5b9a\u7684\u67e5\u8be2\u65b9\u6848\u7684\u8bdd\u53ef\u4ee5\u4f7f\u7528hint;<\/li>\n
                    2. \u8bed\u6cd5:cursor.hint(index);\n
                        \n
                      1. db.mycoll.find().hint(“index_name”):\u901a\u8fc7\u6307\u5b9a\u7d22\u5f15\u540d\u79f0\u6765\u5b9e\u73b0hint;<\/li>\n
                      2. db.mycoll.find().hint({key:value}):\u901a\u8fc7\u6307\u5b9a\u521b\u5efa\u7d22\u5f15\u65f6\u7684key\u7684\u987a\u5e8f\u6765\u5b9e\u73b0hint,\u53ef\u4ee5\u4e4b\u524d\u901a\u8fc7db.mycoll.getIndexes()\u67e5\u770b;<\/li>\n<\/ol>\n<\/li>\n
                      3. \u67e5\u770bhint\u7684\u6027\u80fd:db.mycoll.find().hint(index).explain();<\/li>\n<\/ol>\n<\/li>\n
                      4. \u6ce8\u610f\u4e8b\u9879:\n
                          \n
                        1. MongoDB\u4e2d\u7684\u7d22\u5f15\u662f\u5927\u5c0f\u5199\u654f\u611f\u7684;<\/li>\n
                        2. \u5f53\u66f4\u65b0\u5bf9\u8c61\u65f6,\u53ea\u6709\u5728\u7d22\u5f15\u4e0a\u7684\u8fd9\u4e9bkey\u53d1\u751f\u53d8\u5316\u624d\u66f4\u65b0,\u6240\u4ee5\u63d0\u9ad8\u4e86\u6027\u80fd;\u5f53\u5bf9\u8c61\u589e\u957f\u4e86\u6216\u8005\u79fb\u52a8\u65f6,\u6240\u6709\u7684\u7d22\u5f15\u90fd\u5fc5\u987b\u66f4\u65b0,\u4f1a\u5f88\u6162;<\/li>\n
                        3. \u7d22\u5f15\u7684\u4fe1\u606f\u4f1a\u4fdd\u5b58\u5728system.indexes\u96c6\u5408\u4e2d,\u8fd0\u884cdb.system.indexes.find()\u53ef\u4ee5\u67e5\u770b\u8fd9\u4e9b\u6570\u636e;<\/li>\n
                        4. \u7d22\u5f15\u7684\u5b57\u6bb5\u7684\u5927\u5c0f\u9650\u5236\u76ee\u524d\u662f800bytes,\u5927\u4e8e\u4e4b\u540e\u53ef\u4ee5\u5728\u8fd9\u4e2a\u5b57\u6bb5\u4e0a\u521b\u5efa\u7d22\u5f15,\u4f46\u662f\u8be5\u5b57\u6bb5\u4e0d\u4f1a\u88ab\u7d22\u5f15;<\/li>\n
                        5. \u5982\u679c\u6570\u636e\u96c6\u5408\u6bd4\u8f83\u5c0f(4M),\u53ef\u4ee5\u8054\u5408\u4f7f\u7528limit()\u548csort()\u51fd\u6570\u800c\u4e0d\u9700\u8981\u521b\u5efa\u7d22\u5f15\u6765\u67e5\u8be2\u6570\u636e;<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n
                          <\/div>\n<\/div>\n
                          ———————-\u00a010w\u6761\u6d4b\u8bd5\u6570\u636e\u00a0———————-<\/div>\n
                          db.index.remove()<\/div>\n
                          for(var i = 0; i < 100000; i++){<\/div>\n
                          \u00a0 \u00a0 \u00a0db.index.insert({name:”index”+i, age:i})<\/div>\n
                          }<\/div>\n
                          \"\"<\/div>\n
                          ———————-\u00a010w\u6761\u6d4b\u8bd5\u6570\u636e\u00a0———————-<\/div>\n
                          <\/div>\n
                          ———————- \u7a00\u758f\u7d22\u5f15\u4e0e\u975e\u7a00\u758f\u7d22\u5f15\u7684\u5bf9\u6bd4\u00a0———————-<\/div>\n
                          — 1.\u6d4b\u8bd5\u6570\u636e;<\/div>\n
                          db.sparse.insert({name:”sparse1″, age:20})<\/div>\n
                          db.sparse.insert({name:”sparse2″})<\/div>\n
                          db.sparse.find()<\/div>\n
                          \"\"<\/div>\n
                          <\/div>\n
                          — 2.\u5728age\u5217\u521b\u5efa\u4e00\u4e2a\u7a00\u758f\u7d22\u5f15;<\/div>\n
                          db.sparse.ensureIndex({age:1}, {name:”idx_sparse_age”, sparse:true})<\/div>\n
                          db.sparse.getIndexes()<\/div>\n
                          \"\"<\/div>\n
                          <\/div>\n
                          — 3.\u67e5\u770b\u6570\u636e,\u7a00\u758f\u7d22\u5f15\u4e2d\u4e0d\u5305\u542b\u5217\u4e3anull\u7684\u6587\u6863,\u53ea\u6709\u7a00\u758f\u7d22\u5f15\u4e2d\u7684\u6587\u6863\u624d\u4f1a\u88ab\u8fd4\u56de;<\/div>\n
                          db.sparse.find()<\/div>\n
                          db.sparse.find().sort({age:1})<\/div>\n
                          db.sparse.find({name:{$ne:0}})<\/div>\n
                          \"\"<\/div>\n
                          <\/div>\n
                          — 4.\u5220\u9664\u7a00\u758f\u7d22\u5f15,\u5e76\u521b\u5efa\u4e00\u822c\u7684\u7d22\u5f15;<\/div>\n
                          db.sparse.dropIndex(“idx_sparse_age”)<\/div>\n
                          db.sparse.ensureIndex({age:1}, {name:”idx_sparse_age”})<\/div>\n
                          db.sparse.getIndexes()<\/div>\n
                          \"\"<\/div>\n
                          <\/div>\n
                          — \u67e5\u770b\u6570\u636e,\u975e\u7a00\u758f\u7d22\u5f15\u4e2d\u5305\u542b\u4e86\u5217\u4e3anull\u7684\u6587\u6863;<\/div>\n
                          \"\"<\/div>\n
                          ———————- \u7a00\u758f\u7d22\u5f15\u4e0e\u975e\u7a00\u758f\u7d22\u5f15\u7684\u5bf9\u6bd4\u00a0———————-<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

                          MongoDB\u4e2d\u7684\u6027\u80fd\u5206\u6790\u53ca\u7d22\u5f15\u64cd\u4f5c \u6027\u80fd\u5206\u6790\u51fd\u6570explain(); \u8bed\u6cd5:cursor.explain(v […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[24,25],"class_list":["post-315","post","type-post","status-publish","format-standard","hentry","category-nosql","tag-mongodb","tag-nosql"],"_links":{"self":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts\/315","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=315"}],"version-history":[{"count":0,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts\/315\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=315"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=315"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=315"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}