Importing OSM into MongoDB
Find all pubs:
db.poi.find( { 'tags.amenity' : 'pub' } );
Let's look at the "explain" output:
db.poi.find( { 'tags.amenity' : 'pub' } ).explain();
{
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "demo.poiConcat",
"indexFilterSet" : false,
"parsedQuery" : {
"tags.amenity" : { "$eq" : "pub" }
},
"winningPlan" : {
"stage" : *"COLLSCAN"*,
"filter" : {
"tags.amenity" : { "$eq" : "pub" }
},
"direction" : "forward"
},
"rejectedPlans" : [ ]
},
…
We need an index for that:
db.poi.createIndex( { "tags.amenity" : 1 } );
And the new "explain" output:
db.poi.find( { 'tags.amenity' : 'pub' } ).explain();
…
"winningPlan" : {
"stage" : "FETCH",
"inputStage" : {
*|007700|"stage" : "IXSCAN",|*
"keyPattern" : { "tags.amenity" : 1 },
"indexName" : "tags.amenity_1",
"isMultiKey" : false,
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"tags.amenity" : [ "[\"pub\", \"pub\"]" ]
}
}
},