MongoDB's Index Learning

To learn index classifications and create indexes:
1._ID Index The default index for most collections
2. Single key index: Manually created, a single value
3. Multi-built Index: composite function
4. Composite index: The leftmost prefix principle
5. Expired index: Expire within a certain time, note: must be isodate or its array, do not use timestamp, otherwise it will not be automatically deleted.
6. Full-text index Db.tm.ensureindex ({"article": "Text"}), Db.tm.ensureindex ({"Key1": "Text", "Key2": "Text"}), Db.tm.ensureindex ({$**: "text"})
Query: Db.tm.find ({$text: {$search: "AA"}})
Db.tm.find ({$text: {$search: "AA bb cc"}})
Db.tm.find ({$text: {$search: "AA Bb-cc"}})
Db.tm.find ({$text: {$search: "\" a\ "\" BB "\" Cc\ "}})
Full-text index matching degree $meta
Db.tm.find ({$text: {$search: "AA bb"}},{score:{$meta: "Textscore"}})
Db.tm.find ({$text: {$search: "AA bb"}},{score:{$meta: "Textscore"}}). sort ({score:{$meta: "Textscore"}})
Only $text can be specified at a time
7. Location index (drip taxi, Volkswagen reviews)


2d index (address location index)
Db.localtion.ensureindex ({"W": "2d"})

View index: Db.tm.getIndexes ()
Build Index Db.t1.ensureIndex ({x:1})
Multi-key index Db.tm.ensureIndex ({x:[1,2,3,4,5]})
Composite Index Db.tm.ensureIndex ({x:1,y:1})
Delete index Db.tm.dropIndex ("X_1_y_1")
Db.tm.find ({x:100,y:100}). Explain ()
Expiration index: Db.tm.insert ({time:new Date ()}) Isodate is the current time
Db.tm.ensureIndex ({time:1},{expireafterseconds:10})
Db.tm.insert ({time:new Date (), z:1})
Full-Text Indexing
Db.t1.ensureIndex ({article: "Text"})
Db.t1.insert ({article: "AA bb cc"})
Find Db.t1.find ({$text: {$search: "AA"}})
Db.t1.find ({$text: {$search: "AA bb cc"}}) or relationship
Db.t1.find ({$text: {$search: "AA Bb-cc"}}) does not contain CC
Db.t1.find ({$text: {$search: "\" aa\ "\" bb\ "\"-cc\ "}}) and the relationship


Similarity of full-text indexes: Db.t1.find ({$text: {$search: "AA bb"}},{score:{$meta: "Textscore"}})
Db.t1.find ({$text: {$search: "AA bb"}},{score:{$meta: "Textscore"}}). sort ({score:{$meta: "Textscore"}})



Index naming
Db.t1.ensureIndex ({x:1,y:2,z:2},{name: "xyz"})
Db.t1.dropIndex ("xyz")
Create a unique index
Db.t2.ensureIndex ({m:1,n:1},{unique:true})

View S index existence of a field

Db.abc.find ({m:{$exists: true}})

Create 2d Index: Planar location index, location representation, latitude [Longitude (-180,180), Latitude ( -90,90)]
Db.location.ensureIndex ({"W": "2d"})
Db.location.insert ({w:[1,1]})
Db.location.insert ({w:[1,2]})
Db.location.insert ({w:[3,2]})
Db.location.insert ({w:[32,22]})
Db.location.insert ({w:[100,90]})
Nearest query
Db.location.find ({w:{$near: [Up]}})

Inquire
Db.location.find ({w:{$near: [All], $maxDistance: 10}})

Address Location Index
Geonear
Db.runcommand ({geonear: "Location", near:[1,2],maxdistance:10,num:1})
Db.stats

for (i=1;i<10000;i++) Db.tt.insert ({n:i})

View Run status
/export/mongodb/bin/mongostat-h 192.168.1.70:22222
Faults locked IDX Miss does not use index values
QR|QW Read-write queue


View current level
Db.getprofilingstatus ()
0:profile is off, MongoDB does not log any operations
1 in conjunction with SLOWMS, MongoDB will record any operation over SLOWMS
2 will record any records
Modify Level Profile
Db.setprofilinglevel (0)
Db.system.profile.find (). Sort ({$natural: 1}). Limit (10)
Query sort

Db.system.indexes.find (). Sort ({$nature: 1})

This article is from the "DBSpace" blog, so be sure to keep this source http://dbspace.blog.51cto.com/6873717/1869918

MongoDB's Index Learning