Fazer um query sem index para o campo name utilizando o explain.
db.pokemons.find({name: "Taillow"}).explain('executionStats').executionStats
{
"executionSuccess" : true,
"nReturned" : 1,
"executionTimeMillis" : 0,
"totalKeysExamined" : 0,
"totalDocsExamined" : 610,
"executionStages" : {
"stage" : "COLLSCAN",
"filter" : {
"name" : {
"$eq" : "Taillow"
}
},
"nReturned" : 1,
"executionTimeMillisEstimate" : 0,
"works" : 612,
"advanced" : 1,
"needTime" : 610,
"needFetch" : 0,
"saveState" : 4,
"restoreState" : 4,
"isEOF" : 1,
"invalidates" : 0,
"direction" : "forward",
"docsExamined" : 610
}
}Criar um index para o campo name.
db.pokemons.createIndex({name: 1})
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}Fazer um query com index para o campo name utilizando o explain.
db.pokemons.find({name: "Taillow"}).explain('executionStats').executionStats
{
"executionSuccess" : true,
"nReturned" : 1,
"executionTimeMillis" : 0,
"totalKeysExamined" : 1,
"totalDocsExamined" : 1,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 1,
"executionTimeMillisEstimate" : 0,
"works" : 2,
"advanced" : 1,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 1,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 1,
"executionTimeMillisEstimate" : 0,
"works" : 2,
"advanced" : 1,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 0,
"restoreState" : 0,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"name" : 1
},
"indexName" : "name_1",
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"name" : [
"[\"Taillow\", \"Taillow\"]"
]
},
"keysExamined" : 1,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
}
}Fazer uma query sem index para dois campos juntos utilizando o explain.
var query = {
$and: [
{ attack: { $gte: 50 } },
{ defense: { $gte: 30 } }
]
}
db.pokemons.find(query).explain('executionStats').executionStats
{
"executionSuccess" : true,
"nReturned" : 489,
"executionTimeMillis" : 1,
"totalKeysExamined" : 0,
"totalDocsExamined" : 610,
"executionStages" : {
"stage" : "COLLSCAN",
"filter" : {
"$and" : [
{
"attack" : {
"$gte" : 50
}
},
{
"defense" : {
"$gte" : 30
}
}
]
},
"nReturned" : 489,
"executionTimeMillisEstimate" : 0,
"works" : 612,
"advanced" : 489,
"needTime" : 122,
"needFetch" : 0,
"saveState" : 4,
"restoreState" : 4,
"isEOF" : 1,
"invalidates" : 0,
"direction" : "forward",
"docsExamined" : 610
}
}Criar um index para dois campos juntos.
db.pokemons.createIndex({attack: 1, defense: 1})
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 2,
"numIndexesAfter" : 3,
"ok" : 1
}Fazer uma query com index para dois campos juntos utilizando o explain.
db.pokemons.find(query).explain('executionStats').executionStats
{
"executionSuccess" : true,
"nReturned" : 489,
"executionTimeMillis" : 2,
"totalKeysExamined" : 492,
"totalDocsExamined" : 489,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 489,
"executionTimeMillisEstimate" : 0,
"works" : 493,
"advanced" : 489,
"needTime" : 3,
"needFetch" : 0,
"saveState" : 3,
"restoreState" : 3,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 489,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 489,
"executionTimeMillisEstimate" : 0,
"works" : 492,
"advanced" : 489,
"needTime" : 3,
"needFetch" : 0,
"saveState" : 3,
"restoreState" : 3,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"attack" : 1,
"defense" : 1
},
"indexName" : "attack_1_defense_1",
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"attack" : [
"[50.0, inf.0]"
],
"defense" : [
"[30.0, inf.0]"
]
},
"keysExamined" : 492,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
}
}