同様の質問をいくつか見ましたが、問題は解決しませんでした ( 1、2、3 )。
ほぼ 2M のドキュメントを含むコレクションがあります。私の問題: 非常に単純なクエリ (find({id: 53})) は、ほぼ 5 分間実行されます (以下のすべての関連情報を参照してください)。
「id」フィールドでインデックスを追加しようとしましたが、ヒントを試してみましたが、scanAndOrderは false です。私は十分なメモリを持っています（今のところスワップはなく、サーバーで合計600MBしか使用されていません（まだ約1GBが空いています））。Debian 7 と mongodb 2.4.7 です。
多分これは問題です：昨日私はrepairDatabaseを実行し、その後問題に気づきました（しかし、それが以前だったかどうかはわかりません）。とにかく、コレクションに対して完全な検証を実行しましたが、すべて問題ないようです。また、昨日、もう 1 つのインデックス ({id: 1}) を追加しました。また、今日、コレクションのインデックスを再作成しました。
このような長いクエリの間、ディスクは非常に広範囲に使用されます。
> db.results.count()
1819411
> db.results.stats()
{
"ns" : "spider.results",
"count" : 1819411,
"size" : 26662218768,
"avgObjSize" : 14654.313273911172,
"storageSize" : 28309077856,
"numExtents" : 34,
"nindexes" : 4,
"lastExtentSize" : 2146426864,
"paddingFactor" : 1,
"systemFlags" : 0,
"userFlags" : 0,
"totalIndexSize" : 207245248,
"indexSizes" : {
"_id_" : 53144000,
"datetime_-1" : 45793776,
"id_1_datetime_1" : 62513696,
"id_1" : 45793776
},
"ok" : 1
}
> db.results.getIndices()
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "spider.results",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"datetime" : -1
},
"ns" : "spider.results",
"name" : "datetime_-1"
},
{
"v" : 1,
"key" : {
"id" : 1,
"datetime" : 1
},
"unique" : true,
"ns" : "spider.results",
"name" : "id_1_datetime_1"
},
{
"v" : 1,
"key" : {
"id" : 1
},
"ns" : "spider.results",
"name" : "id_1"
}
]
> db.results.validate(true)
{
"ns" : "spider.results",
"firstExtent" : "0:258000 ns:spider.results",
"lastExtent" : "18:2000 ns:spider.results",
"extentCount" : 34,
"extents" : [
{
"loc" : "0:258000",
"xnext" : "0:25a000",
"xprev" : "null",
"nsdiag" : "spider.results",
"size" : 8192,
"firstRecord" : "0:2580b0",
"lastRecord" : "0:2598b0"
},
{
"loc" : "0:25a000",
"xnext" : "0:29d000",
"xprev" : "0:258000",
"nsdiag" : "spider.results",
"size" : 274432,
"firstRecord" : "0:25a0b0",
"lastRecord" : "0:29c6b0"
},
{
"loc" : "0:29d000",
"xnext" : "0:3a9000",
"xprev" : "0:25a000",
"nsdiag" : "spider.results",
"size" : 1097728,
"firstRecord" : "0:29d0b0",
"lastRecord" : "0:3a6c30"
},
{
"loc" : "0:3a9000",
"xnext" : "0:7d9000",
"xprev" : "0:29d000",
"nsdiag" : "spider.results",
"size" : 4390912,
"firstRecord" : "0:3a90b0",
"lastRecord" : "0:7d8ab0"
},
{
"loc" : "0:7d9000",
"xnext" : "0:d81000",
"xprev" : "0:3a9000",
"nsdiag" : "spider.results",
"size" : 5931008,
"firstRecord" : "0:7d90b0",
"lastRecord" : "0:d7fcb0"
},
{
"loc" : "0:d81000",
"xnext" : "0:1524000",
"xprev" : "0:7d9000",
"nsdiag" : "spider.results",
"size" : 8007680,
"firstRecord" : "0:d810b0",
"lastRecord" : "0:15238b0"
},
{
"loc" : "0:1524000",
"xnext" : "0:1f74000",
"xprev" : "0:d81000",
"nsdiag" : "spider.results",
"size" : 10813440,
"firstRecord" : "0:15240b0",
"lastRecord" : "0:1f73ab0"
},
{
"loc" : "0:1f74000",
"xnext" : "1:2000",
"xprev" : "0:1524000",
"nsdiag" : "spider.results",
"size" : 14598144,
"firstRecord" : "0:1f740b0",
"lastRecord" : "0:2d5f6b0"
},
{
"loc" : "1:2000",
"xnext" : "1:12ce000",
"xprev" : "0:1f74000",
"nsdiag" : "spider.results",
"size" : 19709952,
"firstRecord" : "1:20b0",
"lastRecord" : "1:12cd8b0"
},
{
"loc" : "1:12ce000",
"xnext" : "1:2c2f000",
"xprev" : "1:2000",
"nsdiag" : "spider.results",
"size" : 26611712,
"firstRecord" : "1:12ce0b0",
"lastRecord" : "1:2c2eab0"
},
{
"loc" : "1:2c2f000",
"xnext" : "1:4e72000",
"xprev" : "1:12ce000",
"nsdiag" : "spider.results",
"size" : 35926016,
"firstRecord" : "1:2c2f0b0",
"lastRecord" : "1:4e719b0"
},
{
"loc" : "1:4e72000",
"xnext" : "2:2000",
"xprev" : "1:2c2f000",
"nsdiag" : "spider.results",
"size" : 48500736,
"firstRecord" : "1:4e720b0",
"lastRecord" : "1:7cb27b0"
},
{
"loc" : "2:2000",
"xnext" : "2:3e74000",
"xprev" : "1:4e72000",
"nsdiag" : "spider.results",
"size" : 65478656,
"firstRecord" : "2:20b0",
"lastRecord" : "2:3e71d30"
},
{
"loc" : "2:3e74000",
"xnext" : "3:2000",
"xprev" : "2:2000",
"nsdiag" : "spider.results",
"size" : 88399872,
"firstRecord" : "2:3e740b0",
"lastRecord" : "2:92c1ab0"
},
{
"loc" : "3:2000",
"xnext" : "3:71d2000",
"xprev" : "2:3e74000",
"nsdiag" : "spider.results",
"size" : 119341056,
"firstRecord" : "3:20b0",
"lastRecord" : "3:71d1ab0"
},
{
"loc" : "3:71d2000",
"xnext" : "3:10b78000",
"xprev" : "3:2000",
"nsdiag" : "spider.results",
"size" : 161112064,
"firstRecord" : "3:71d20b0",
"lastRecord" : "3:10b70ab0"
},
{
"loc" : "3:10b78000",
"xnext" : "4:2000",
"xprev" : "3:71d2000",
"nsdiag" : "spider.results",
"size" : 217501696,
"firstRecord" : "3:10b780b0",
"lastRecord" : "3:1dae29b0"
},
{
"loc" : "4:2000",
"xnext" : "4:11809000",
"xprev" : "3:10b78000",
"nsdiag" : "spider.results",
"size" : 293629952,
"firstRecord" : "4:20b0",
"lastRecord" : "4:118088b0"
},
{
"loc" : "4:11809000",
"xnext" : "5:2000",
"xprev" : "4:2000",
"nsdiag" : "spider.results",
"size" : 396402688,
"firstRecord" : "4:118090b0",
"lastRecord" : "4:29212930"
},
{
"loc" : "5:2000",
"xnext" : "5:1fe5d000",
"xprev" : "4:11809000",
"nsdiag" : "spider.results",
"size" : 535146496,
"firstRecord" : "5:20b0",
"lastRecord" : "5:1fe5ca30"
},
{
"loc" : "5:1fe5d000",
"xnext" : "6:2000",
"xprev" : "5:2000",
"nsdiag" : "spider.results",
"size" : 722448384,
"firstRecord" : "5:1fe5d0b0",
"lastRecord" : "5:4af553b0"
},
{
"loc" : "6:2000",
"xnext" : "7:2000",
"xprev" : "5:1fe5d000",
"nsdiag" : "spider.results",
"size" : 975306752,
"firstRecord" : "6:20b0",
"lastRecord" : "6:3a21d6b0"
},
{
"loc" : "7:2000",
"xnext" : "8:2000",
"xprev" : "6:2000",
"nsdiag" : "spider.results",
"size" : 1316667392,
"firstRecord" : "7:20b0",
"lastRecord" : "7:4e7ab0b0"
},
{
"loc" : "8:2000",
"xnext" : "9:2000",
"xprev" : "7:2000",
"nsdiag" : "spider.results",
"size" : 1777504256,
"firstRecord" : "8:20b0",
"lastRecord" : "8:69f278b0"
},
{
"loc" : "9:2000",
"xnext" : "10:2000",
"xprev" : "8:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "9:20b0",
"lastRecord" : "9:7fefdab0"
},
{
"loc" : "10:2000",
"xnext" : "11:2000",
"xprev" : "9:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "10:20b0",
"lastRecord" : "10:7feff630"
},
{
"loc" : "11:2000",
"xnext" : "12:2000",
"xprev" : "10:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "11:20b0",
"lastRecord" : "11:7feffa30"
},
{
"loc" : "12:2000",
"xnext" : "13:2000",
"xprev" : "11:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "12:20b0",
"lastRecord" : "12:7feffb30"
},
{
"loc" : "13:2000",
"xnext" : "14:2000",
"xprev" : "12:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "13:20b0",
"lastRecord" : "13:7fefb7b0"
},
{
"loc" : "14:2000",
"xnext" : "15:2000",
"xprev" : "13:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "14:20b0",
"lastRecord" : "14:7feffb30"
},
{
"loc" : "15:2000",
"xnext" : "16:2000",
"xprev" : "14:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "15:20b0",
"lastRecord" : "15:7fefba30"
},
{
"loc" : "16:2000",
"xnext" : "17:2000",
"xprev" : "15:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "16:20b0",
"lastRecord" : "16:7feff9b0"
},
{
"loc" : "17:2000",
"xnext" : "18:2000",
"xprev" : "16:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "17:20b0",
"lastRecord" : "17:7feff9b0"
},
{
"loc" : "18:2000",
"xnext" : "null",
"xprev" : "17:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "18:20b0",
"lastRecord" : "18:1f8328b0"
}
],
"datasize" : 26662218768,
"nrecords" : 1819411,
"lastExtentSize" : 2146426864,
"padding" : 1,
"firstExtentDetails" : {
"loc" : "0:258000",
"xnext" : "0:25a000",
"xprev" : "null",
"nsdiag" : "spider.results",
"size" : 8192,
"firstRecord" : "0:2580b0",
"lastRecord" : "0:2598b0"
},
"lastExtentDetails" : {
"loc" : "18:2000",
"xnext" : "null",
"xprev" : "17:2000",
"nsdiag" : "spider.results",
"size" : 2146426864,
"firstRecord" : "18:20b0",
"lastRecord" : "18:1f8328b0"
},
"objectsFound" : 1819411,
"invalidObjects" : 0,
"bytesWithHeaders" : 26691329344,
"bytesWithoutHeaders" : 26662218768,
"deletedCount" : 14,
"deletedSize" : 1617742528,
"nIndexes" : 4,
"keysPerIndex" : {
"spider.results.$_id_" : 1819411,
"spider.results.$datetime_-1" : 1819411,
"spider.results.$id_1_datetime_1" : 1819411,
"spider.results.$id_1" : 1819411
},
"valid" : true,
"errors" : [ ],
"ok" : 1
}
> db.results.find({id:6}).explain()
{
"cursor" : "BtreeCursor id_1_datetime_1",
"isMultiKey" : false,
"n" : 47402,
"nscannedObjects" : 47402,
"nscanned" : 47402,
"nscannedObjectsAllPlans" : 47402,
"nscannedAllPlans" : 47402,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 248,
"nChunkSkips" : 0,
"millis" : 254485,
"indexBounds" : {
"id" : [
[
6,
6
]
],
"datetime" : [
[
{
"$minElement" : 1
},
{
"$maxElement" : 1
}
]
]
},
"server" : "ip-10-137-56-52:27017"
}
まだ行っていない唯一のことは、修復を伴うバックアップと復元です。しかし、それが役立つかどうかはわかりません...
助言がありますか？