mongo索引创建和索引分析

for(i=0; i<20000; i++){
... db.numbers.save({num: i});
... }
WriteResult({ "nInserted" : 1 })
> db.numbers.count()
20000
> db.numbers.find()
{ "_id" : ObjectId("59455ad5961eb6f4b52b6762"), "num" : 0 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6763"), "num" : 1 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6764"), "num" : 2 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6765"), "num" : 3 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6766"), "num" : 4 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6767"), "num" : 5 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6768"), "num" : 6 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6769"), "num" : 7 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b676a"), "num" : 8 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b676b"), "num" : 9 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b676c"), "num" : 10 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b676d"), "num" : 11 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b676e"), "num" : 12 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b676f"), "num" : 13 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6770"), "num" : 14 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6771"), "num" : 15 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6772"), "num" : 16 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6773"), "num" : 17 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6774"), "num" : 18 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6775"), "num" : 19 }
Type "it" for more
> it
{ "_id" : ObjectId("59455ad5961eb6f4b52b6776"), "num" : 20 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6777"), "num" : 21 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6778"), "num" : 22 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6779"), "num" : 23 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677a"), "num" : 24 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677b"), "num" : 25 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677c"), "num" : 26 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677d"), "num" : 27 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677e"), "num" : 28 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677f"), "num" : 29 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6780"), "num" : 30 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6781"), "num" : 31 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6782"), "num" : 32 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6783"), "num" : 33 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6784"), "num" : 34 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6785"), "num" : 35 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6786"), "num" : 36 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6787"), "num" : 37 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6788"), "num" : 38 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6789"), "num" : 39 }
Type "it" for more
> db.numbers.find({num:500})
{ "_id" : ObjectId("59455ad5961eb6f4b52b6956"), "num" : 500 }
> db.numbers.find({num:{"$gt":19995}})
{ "_id" : ObjectId("59455adb961eb6f4b52bb57e"), "num" : 19996 }
{ "_id" : ObjectId("59455adb961eb6f4b52bb57f"), "num" : 19997 }
{ "_id" : ObjectId("59455adb961eb6f4b52bb580"), "num" : 19998 }
{ "_id" : ObjectId("59455adb961eb6f4b52bb581"), "num" : 19999 }
> db.numbers.find({num:{"$gt":20, "$lt":25}})
{ "_id" : ObjectId("59455ad5961eb6f4b52b6777"), "num" : 21 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6778"), "num" : 22 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6779"), "num" : 23 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677a"), "num" : 24 }
> db.numbers.find({num:{"$gte":20, "$lte":25}})
{ "_id" : ObjectId("59455ad5961eb6f4b52b6776"), "num" : 20 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6777"), "num" : 21 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6778"), "num" : 22 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b6779"), "num" : 23 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677a"), "num" : 24 }
{ "_id" : ObjectId("59455ad5961eb6f4b52b677b"), "num" : 25 }
> db.numbers.find({num:{"$gt":19995}}).explain("executionStats")
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "tutorial.numbers",
"indexFilterSet" : false,
"parsedQuery" : {
"num" : {
"$gt" : 19995
}
},
"winningPlan" : {
"stage" : "COLLSCAN",
"filter" : {
"num" : {
"$gt" : 19995
}
},
"direction" : "forward"
},
"rejectedPlans" : [ ]
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 4,
"executionTimeMillis" : 10,
"totalKeysExamined" : 0,
"totalDocsExamined" : 20000,
"executionStages" : {
"stage" : "COLLSCAN",
"filter" : {
"num" : {
"$gt" : 19995
}
},
"nReturned" : 4,
"executionTimeMillisEstimate" : 11,
"works" : 20002,
"advanced" : 4,
"needTime" : 19997,
"needYield" : 0,
"saveState" : 156,
"restoreState" : 156,
"isEOF" : 1,
"invalidates" : 0,
"direction" : "forward",
"docsExamined" : 20000
}
},
"serverInfo" : {
"host" : "GuGangdeMacBook-Pro.local",
"port" : 27017,
"version" : "3.4.4",
"gitVersion" : "888390515874a9debd1b6c5d36559ca86b44babd"
},
"ok" : 1
}
> db.numbers.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "tutorial.numbers"
}
]
> db.numbers.creatIndex({num:1})
2017-06-18T00:46:35.030+0800 E QUERY    [thread1] TypeError: db.numbers.creatIndex is not a function :
@(shell):1:1
> db.numbers.createIndex({num:1})
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
> db.numbers.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "tutorial.numbers"
},
{
"v" : 2,
"key" : {
"num" : 1
},
"name" : "num_1",
"ns" : "tutorial.numbers"
}
]
> db.numbers.find({num:{"$gt":19995}}).explain("executionStats")
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "tutorial.numbers",
"indexFilterSet" : false,
"parsedQuery" : {
"num" : {
"$gt" : 19995
}
},
"winningPlan" : {
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"num" : 1
},
"indexName" : "num_1",
"isMultiKey" : false,
"multiKeyPaths" : {
"num" : [ ]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2,
"direction" : "forward",
"indexBounds" : {
"num" : [
"(19995.0, inf.0]"
]
}
}
},
"rejectedPlans" : [ ]
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 4,
"executionTimeMillis" : 4,
"totalKeysExamined" : 4,
"totalDocsExamined" : 4,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 4,
"executionTimeMillisEstimate" : 0,
"works" : 5,
"advanced" : 4,
"needTime" : 0,
"needYield" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 4,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 4,
"executionTimeMillisEstimate" : 0,
"works" : 5,
"advanced" : 4,
"needTime" : 0,
"needYield" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"num" : 1
},
"indexName" : "num_1",
"isMultiKey" : false,
"multiKeyPaths" : {
"num" : [ ]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2,
"direction" : "forward",
"indexBounds" : {
"num" : [
"(19995.0, inf.0]"
]
},
"keysExamined" : 4,
"seeks" : 1,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0
}
}
},
"serverInfo" : {
"host" : "GuGangdeMacBook-Pro.local",
"port" : 27017,
"version" : "3.4.4",
"gitVersion" : "888390515874a9debd1b6c5d36559ca86b44babd"
},
"ok" : 1
}
> db.numbers.find({num:{"$gt":19995}}).explain("executionStats")
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "tutorial.numbers",
"indexFilterSet" : false,
"parsedQuery" : {
"num" : {
"$gt" : 19995
}
},
"winningPlan" : {
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"num" : 1
},
"indexName" : "num_1",
"isMultiKey" : false,
"multiKeyPaths" : {
"num" : [ ]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2,
"direction" : "forward",
"indexBounds" : {
"num" : [
"(19995.0, inf.0]"
]
}
}
},
"rejectedPlans" : [ ]
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 4,
"executionTimeMillis" : 0,
"totalKeysExamined" : 4,
"totalDocsExamined" : 4,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 4,
"executionTimeMillisEstimate" : 0,
"works" : 5,
"advanced" : 4,
"needTime" : 0,
"needYield" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 4,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 4,
"executionTimeMillisEstimate" : 0,
"works" : 5,
"advanced" : 4,
"needTime" : 0,
"needYield" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"num" : 1
},
"indexName" : "num_1",
"isMultiKey" : false,
"multiKeyPaths" : {
"num" : [ ]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2,
"direction" : "forward",
"indexBounds" : {
"num" : [
"(19995.0, inf.0]"
]
},
"keysExamined" : 4,
"seeks" : 1,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0
}
}
},
"serverInfo" : {
"host" : "GuGangdeMacBook-Pro.local",
"port" : 27017,
"version" : "3.4.4",
"gitVersion" : "888390515874a9debd1b6c5d36559ca86b44babd"
},
"ok" : 1
}
> db.stats()
{
"db" : "tutorial",
"collections" : 1,
"views" : 0,
"objects" : 20000,
"avgObjSize" : 35,
"dataSize" : 700000,
"storageSize" : 352256,
"numExtents" : 0,
"indexes" : 2,
"indexSize" : 425984,
"ok" : 1
}
> db.numbers.stats()
{
"ns" : "tutorial.numbers",
"size" : 700000,
"count" : 20000,
"avgObjSize" : 35,
"storageSize" : 352256,
"capped" : false,
"wiredTiger" : {
"metadata" : {
"formatVersion" : 1
},
"creationString" : "access_pattern_hint=none,allocation_size=4KB,app_metadata=(formatVersion=1),block_allocation=best,block_compressor=snappy,cache_resident=false,checksum=on,colgroups=,collator=,columns=,dictionary=0,encryption=(keyid=,name=),exclusive=false,extractor=,format=btree,huffman_key=,huffman_value=,ignore_in_memory_cache_size=false,immutable=false,internal_item_max=0,internal_key_max=0,internal_key_truncate=true,internal_page_max=4KB,key_format=q,key_gap=10,leaf_item_max=0,leaf_key_max=0,leaf_page_max=32KB,leaf_value_max=64MB,log=(enabled=true),lsm=(auto_throttle=true,bloom=true,bloom_bit_count=16,bloom_config=,bloom_hash_count=8,bloom_oldest=false,chunk_count_limit=0,chunk_max=5GB,chunk_size=10MB,merge_max=15,merge_min=0),memory_page_max=10m,os_cache_dirty_max=0,os_cache_max=0,prefix_compression=false,prefix_compression_min=4,source=,split_deepen_min_child=0,split_deepen_per_child=0,split_pct=90,type=file,value_format=u",
"type" : "file",
"uri" : "statistics:table:collection-2--2591950180216266366",
"LSM" : {
"bloom filter false positives" : 0,
"bloom filter hits" : 0,
"bloom filter misses" : 0,
"bloom filter pages evicted from cache" : 0,
"bloom filter pages read into cache" : 0,
"bloom filters in the LSM tree" : 0,
"chunks in the LSM tree" : 0,
"highest merge generation in the LSM tree" : 0,
"queries that could have benefited from a Bloom filter that did not exist" : 0,
"sleep for LSM checkpoint throttle" : 0,
"sleep for LSM merge throttle" : 0,
"total size of bloom filters" : 0
},
"block-manager" : {
"allocations requiring file extension" : 30,
"blocks allocated" : 30,
"blocks freed" : 0,
"checkpoint size" : 339968,
"file allocation unit size" : 4096,
"file bytes available for reuse" : 0,
"file magic number" : 120897,
"file major version number" : 1,
"file size in bytes" : 352256,
"minor version number" : 0
},
"btree" : {
"btree checkpoint generation" : 30,
"column-store fixed-size leaf pages" : 0,
"column-store internal pages" : 0,
"column-store variable-size RLE encoded values" : 0,
"column-store variable-size deleted values" : 0,
"column-store variable-size leaf pages" : 0,
"fixed-record size" : 0,
"maximum internal page key size" : 368,
"maximum internal page size" : 4096,
"maximum leaf page key size" : 2867,
"maximum leaf page size" : 32768,
"maximum leaf page value size" : 67108864,
"maximum tree depth" : 3,
"number of key/value pairs" : 0,
"overflow pages" : 0,
"pages rewritten by compaction" : 0,
"row-store internal pages" : 0,
"row-store leaf pages" : 0
},
"cache" : {
"bytes currently in the cache" : 2015421,
"bytes read into cache" : 0,
"bytes written from cache" : 792943,
"checkpoint blocked page eviction" : 0,
"data source pages selected for eviction unable to be evicted" : 0,
"hazard pointer blocked page eviction" : 0,
"in-memory page passed criteria to be split" : 0,
"in-memory page splits" : 0,
"internal pages evicted" : 0,
"internal pages split during eviction" : 0,
"leaf pages split during eviction" : 0,
"modified pages evicted" : 0,
"overflow pages read into cache" : 0,
"overflow values cached in memory" : 0,
"page split during eviction deepened the tree" : 0,
"page written requiring lookaside records" : 0,
"pages read into cache" : 0,
"pages read into cache requiring lookaside entries" : 0,
"pages requested from the cache" : 20947,
"pages written from cache" : 29,
"pages written requiring in-memory restoration" : 0,
"tracked dirty bytes in the cache" : 0,
"unmodified pages evicted" : 0
},
"cache_walk" : {
"Average difference between current eviction generation when the page was last considered" : 0,
"Average on-disk page image size seen" : 0,
"Clean pages currently in cache" : 0,
"Current eviction generation" : 0,
"Dirty pages currently in cache" : 0,
"Entries in the root page" : 0,
"Internal pages currently in cache" : 0,
"Leaf pages currently in cache" : 0,
"Maximum difference between current eviction generation when the page was last considered" : 0,
"Maximum page size seen" : 0,
"Minimum on-disk page image size seen" : 0,
"On-disk page image sizes smaller than a single allocation unit" : 0,
"Pages created in memory and never written" : 0,
"Pages currently queued for eviction" : 0,
"Pages that could not be queued for eviction" : 0,
"Refs skipped during cache traversal" : 0,
"Size of the root page" : 0,
"Total number of pages currently in cache" : 0
},
"compression" : {
"compressed pages read" : 0,
"compressed pages written" : 28,
"page written failed to compress" : 0,
"page written was too small to compress" : 1,
"raw compression call failed, additional data available" : 0,
"raw compression call failed, no additional data available" : 0,
"raw compression call succeeded" : 0
},
"cursor" : {
"bulk-loaded cursor-insert calls" : 0,
"create calls" : 3,
"cursor-insert key and value bytes inserted" : 751426,
"cursor-remove key bytes removed" : 0,
"cursor-update value bytes updated" : 0,
"insert calls" : 20000,
"next calls" : 120107,
"prev calls" : 1,
"remove calls" : 0,
"reset calls" : 20949,
"restarted searches" : 0,
"search calls" : 8,
"search near calls" : 938,
"truncate calls" : 0,
"update calls" : 0
},
"reconciliation" : {
"dictionary matches" : 0,
"fast-path pages deleted" : 0,
"internal page key bytes discarded using suffix compression" : 55,
"internal page multi-block writes" : 0,
"internal-page overflow keys" : 0,
"leaf page key bytes discarded using prefix compression" : 0,
"leaf page multi-block writes" : 1,
"leaf-page overflow keys" : 0,
"maximum blocks required for a page" : 28,
"overflow values written" : 0,
"page checksum matches" : 0,
"page reconciliation calls" : 2,
"page reconciliation calls for eviction" : 0,
"pages deleted" : 0
},
"session" : {
"object compaction" : 0,
"open cursor count" : 3
},
"transaction" : {
"update conflicts" : 0
}
},
"nindexes" : 2,
"totalIndexSize" : 425984,
"indexSizes" : {
"_id_" : 192512,
"num_1" : 233472
},
"ok" : 1
}