-
Type:
Bug
-
Resolution: Duplicate
-
Priority:
Major - P3
-
None
-
Affects Version/s: 3.0.1
-
Component/s: Querying
-
Labels:None
-
ALL
find() with the $all keyword is slow even on indexed fields. The query planner chooses a plan requiring examining many extra documents, even though it could use an index intersection. It seems that the collection scan is the first to return the 101 entries, but the executionTimeMillisEstimate is much higher (2060 vs 10) than for the AND_SORTED query, which should be the fastest. I'm not sure why the collection scan is beating the AND_SORTED query, given the radically different executionTimeMillisEstimate.
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{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "shangrila.materials",
"indexFilterSet" : false,
"parsedQuery" : {
"$and" : [
{
"elements" : {
"$eq" : "Li"
}
},
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"winningPlan" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
]
}
}
},
"rejectedPlans" : [
{
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"elements" : 1,
"nelements" : 1
},
"indexName" : "elements_1_nelements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
],
"nelements" : [
"[MinKey, MaxKey]"
]
}
}
},
{
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "Li"
}
},
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"inputStage" : {
"stage" : "AND_SORTED",
"inputStages" : [
{
"stage" : "IXSCAN",
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
]
}
},
{
"stage" : "IXSCAN",
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"F\", \"F\"]"
]
}
},
{
"stage" : "IXSCAN",
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Mn\", \"Mn\"]"
]
}
}
]
}
}
]
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 1297,
"executionTimeMillis" : 77874,
"totalKeysExamined" : 59901,
"totalDocsExamined" : 59901,
"executionStages" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"nReturned" : 1297,
"executionTimeMillisEstimate" : 74860,
"works" : 59902,
"advanced" : 1297,
"needTime" : 58604,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 59901,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 59901,
"executionTimeMillisEstimate" : 220,
"works" : 59902,
"advanced" : 59901,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
]
},
"keysExamined" : 59901,
"dupsTested" : 59901,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
},
"allPlansExecution" : [
{
"nReturned" : 88,
"executionTimeMillisEstimate" : 2471,
"totalKeysExamined" : 3985,
"totalDocsExamined" : 3985,
"executionStages" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"nReturned" : 88,
"executionTimeMillisEstimate" : 2471,
"works" : 3985,
"advanced" : 88,
"needTime" : 3897,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"docsExamined" : 3985,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 3985,
"executionTimeMillisEstimate" : 0,
"works" : 3985,
"advanced" : 3985,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"keyPattern" : {
"elements" : 1,
"nelements" : 1
},
"indexName" : "elements_1_nelements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
],
"nelements" : [
"[MinKey, MaxKey]"
]
},
"keysExamined" : 3985,
"dupsTested" : 3985,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
}
},
{
"nReturned" : 62,
"executionTimeMillisEstimate" : 10,
"totalKeysExamined" : 3985,
"totalDocsExamined" : 62,
"executionStages" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "Li"
}
},
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"nReturned" : 62,
"executionTimeMillisEstimate" : 10,
"works" : 3985,
"advanced" : 62,
"needTime" : 3923,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"docsExamined" : 62,
"alreadyHasObj" : 21,
"inputStage" : {
"stage" : "AND_SORTED",
"nReturned" : 62,
"executionTimeMillisEstimate" : 10,
"works" : 3985,
"advanced" : 62,
"needTime" : 3923,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"flagged" : 0,
"matchTested" : 0,
"failedAnd_0" : 347,
"failedAnd_1" : 278,
"failedAnd_2" : 109,
"inputStages" : [
{
"stage" : "IXSCAN",
"nReturned" : 2215,
"executionTimeMillisEstimate" : 0,
"works" : 2215,
"advanced" : 2215,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
]
},
"keysExamined" : 2215,
"dupsTested" : 2215,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
},
{
"stage" : "IXSCAN",
"nReturned" : 1083,
"executionTimeMillisEstimate" : 10,
"works" : 1083,
"advanced" : 1083,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"F\", \"F\"]"
]
},
"keysExamined" : 1083,
"dupsTested" : 1083,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
},
{
"stage" : "IXSCAN",
"nReturned" : 687,
"executionTimeMillisEstimate" : 0,
"works" : 687,
"advanced" : 687,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 3878,
"restoreState" : 3878,
"isEOF" : 0,
"invalidates" : 0,
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Mn\", \"Mn\"]"
]
},
"keysExamined" : 687,
"dupsTested" : 687,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
]
}
}
},
{
"nReturned" : 101,
"executionTimeMillisEstimate" : 2060,
"totalKeysExamined" : 3985,
"totalDocsExamined" : 3985,
"executionStages" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"elements" : {
"$eq" : "F"
}
},
{
"elements" : {
"$eq" : "Mn"
}
}
]
},
"nReturned" : 101,
"executionTimeMillisEstimate" : 2060,
"works" : 3985,
"advanced" : 101,
"needTime" : 3884,
"needFetch" : 0,
"saveState" : 233,
"restoreState" : 233,
"isEOF" : 0,
"invalidates" : 0,
"docsExamined" : 3985,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 3985,
"executionTimeMillisEstimate" : 10,
"works" : 3985,
"advanced" : 3985,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 233,
"restoreState" : 233,
"isEOF" : 0,
"invalidates" : 0,
"keyPattern" : {
"elements" : 1
},
"indexName" : "elements_1",
"isMultiKey" : true,
"direction" : "forward",
"indexBounds" : {
"elements" : [
"[\"Li\", \"Li\"]"
]
},
"keysExamined" : 3985,
"dupsTested" : 3985,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
}
}
]
},
"serverInfo" : {
"host" : "xxxx",
"port" : 27017,
"version" : "3.0.1",
"gitVersion" : "534b5a3f9d10f00cd27737fbcd951032248b5952"
},
"ok" : 1
}
- duplicates
-
SERVER-13740 Improve plan ranking for index intersection
-
- Backlog
-