2
我在每个文档中都有一个带有locked
字段的集合。 我有以下指标:MongoDB可能扫描文件以查找可能被索引覆盖的操作
{
locked : 1
}
当我执行这个解释在计数操作
db.scheduled.find({locked: false}).explain({executionStats:1})
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "connectivity_recruiter.scheduled",
"indexFilterSet" : false,
"parsedQuery" : {
"locked" : {
"$eq" : false
}
},
"winningPlan" : {
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"locked" : 1
},
"indexName" : "locked_1",
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"locked" : [
"[false, false]"
]
}
}
},
.....
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 53045,
"executionTimeMillis" : 299,
"totalKeysExamined" : 53045,
"totalDocsExamined" : 53045,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 53045,
"executionTimeMillisEstimate" : 180,
"works" : 53046,
"advanced" : 53045,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 417,
"restoreState" : 417,
"isEOF" : 1,
"invalidates" : 0,
"docsExamined" : 53045,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 53045,
"executionTimeMillisEstimate" : 70,
"works" : 53046,
"advanced" : 53045,
"needTime" : 0,
"needFetch" : 0,
"saveState" : 417,
"restoreState" : 417,
"isEOF" : 1,
"invalidates" : 0,
"keyPattern" : {
"locked" : 1
},
"indexName" : "locked_1",
"isMultiKey" : false,
"direction" : "forward",
"indexBounds" : {
"locked" : [
"[false, false]"
]
},
"keysExamined" : 53045,
"dupsTested" : 0,
"dupsDropped" : 0,
"seenInvalidated" : 0,
"matchTested" : 0
}
},
...........
}
totalDocsExamined似乎表明,所有的文件,以便进行扫描算来,而这个操作可能是通过单独使用索引执行。 发生了什么?这是正常的吗?对收藏进行全面扫描吗?
感谢检查