MongoDb geoIntersects不';不要随意使用
我有一个名为search2的集合,其中包含大约20000个文档,如下所示:MongoDb geoIntersects不';不要随意使用,mongodb,indexing,explain,2dsphere,Mongodb,Indexing,Explain,2dsphere,我有一个名为search2的集合,其中包含大约20000个文档,如下所示: { "loc": { "type": "Polygon", "coordinates": [ [ [ 43.78526674007639, 11.14739998758569 ], [
{
"loc": {
"type": "Polygon",
"coordinates": [
[
[
43.78526674007639,
11.14739998758569
],
[
43.78526674007639,
11.183372851822439
],
[
43.79443488391605,
11.183372851822439
],
[
43.79443488391605,
11.264311796355125
],
[
43.812771171595415,
11.264311796355125
],
[
43.83110745927479,
11.264311796355125
],
[
43.83110745927479,
11.273305012414314
],
[
43.849443746954144,
11.273305012414314
],
[
43.858611890793824,
11.273305012414314
],
[
43.858611890793824,
11.264311796355125
],
[
43.8769481784732,
11.264311796355125
],
[
43.8769481784732,
11.246325364236752
],
[
43.88611632231286,
11.246325364236752
],
[
43.88611632231286,
11.237332148177565
],
[
43.895284466152546,
11.237332148177565
],
[
43.895284466152546,
11.228338932118376
],
[
43.904452609992234,
11.228338932118376
],
[
43.904452609992234,
11.165386419704065
],
[
43.895284466152546,
11.165386419704065
],
[
43.895284466152546,
11.156393203644878
],
[
43.88611632231286,
11.156393203644878
],
[
43.8769481784732,
11.156393203644878
],
[
43.858611890793824,
11.156393203644878
],
[
43.849443746954144,
11.156393203644878
],
[
43.849443746954144,
11.165386419704065
],
[
43.83110745927479,
11.165386419704065
],
[
43.83110745927479,
11.156393203644878
],
[
43.812771171595415,
11.156393203644878
],
[
43.812771171595415,
11.14739998758569
],
[
43.79443488391605,
11.14739998758569
],
[
43.78526674007639,
11.14739998758569
]
]
]
},
"docId": 1,
"docVote": 0,
"title": "title-1",
"_id": {
"$oid": "5248725d2dd5622510000001"
}
}
我使用以下命令定义索引:
db.search2.ensureIndex({"loc":"2dsphere"});
集合上只有此索引和“\u id”字段上的默认索引
执行以下查询时,我希望解释中的indexOnly参数设置为true:
db.search2.find({
loc: {
$geoIntersects: {
$geometry: {
type: "Polygon",
coordinates: [
[
[43.7269795, 11.1540365],
[43.7269796, 11.1540365],
[43.7269796, 11.1540366],
[43.7269795, 11.1540366],
[43.7269795, 11.1540365]
]
]
}
}
}
}, {
loc: 1,
_id: 0
}).hint({"loc":"2dsphere"}).explain()
但结果是:
{
"cursor" : "S2Cursor",
"isMultiKey" : true,
"n" : 14,
"nscannedObjects" : 14,
"nscanned" : 186,
"nscannedObjectsAllPlans" : 14,
"nscannedAllPlans" : 186,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 20,
"indexBounds" : {
},
"nscanned" : 186,
"matchTested" : NumberLong(80),
"geoTested" : NumberLong(80),
"cellsInCover" : NumberLong(1),
"server" : "*******"
}
我注意到isMultiKey是真的,这是由文档多边形语法引起的。
游标是S2Cursor,所以我假设使用了索引。
但为什么indexOnly是假的?是由于多边形语法吗?那么不可能有IndexOnly=true吗?
提前感谢来自各州的间接解释: indexOnly是一个布尔值,当游标字段中指示的索引覆盖查询时,该值返回true。当一个索引 覆盖一个查询,MongoDB可以匹配查询条件并返回 结果仅使用索引,因为:
- 查询中的所有字段都是该索引的一部分,并且
- 查询中的所有字段都是该索引的一部分,并且
- 集合中任何文档中的任何索引字段都包含一个数组。如果索引字段是数组,则索引变为 多键索引,不支持覆盖查询
- 任何索引字段都是子文档中的字段
希望它能有所帮助我同意你的看法,但我如何才能使用$GEOCERSECTS进行查询,以及indexOnly在哪里是真的?从文件上看,这似乎是不可能的。这是真的吗?感谢您,从文档中我得出了相同的结论,因为多键索引不能覆盖查询。