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Generate data - 20K large objects and related 2d compound index
function generateData(count, uniqueAppIds) {
appIds = []
for (i = 0; i < uniqueAppIds; ++i) {
appIds[i] = ObjectId();
}
dummyx = new Array(10000);
dummyx = dummyx.join( "ABCDEFGHIJKLMNOPQRSTUVWXYZ" );
for (i = 0; i < count; i++) {
doc = {
extra_s: dummyx,
xid: appIds[ Math .round( Math .random() * 9)],
pos: [ Math .round( Math .random() * 360) - 180, Math .round( Math .random() * 180) - 90]
};
db.places.insert(doc);
}
/* Ensure Indices */
db.places.ensureIndex({pos: "2d" , xid: 1});
}
function generateData(20000, 100)
drop vm cache
# on MacOS this would be
sudo purge
Run the query that is expected to work fine
db.places.find({pos: { $nearSphere: [ 0, 0 ], $maxDistance: 125}, xid: ObjectId( "547dbbe1290b9685990ca000" ), xix: 1}).explain()
{
"cursor" : "GeoSearchCursor",
"isMultiKey" : false,
"n" : 0,
"nscannedObjects" : 0,
"nscanned" : 20000,
"nscannedObjectsAllPlans" : 0,
"nscannedAllPlans" : 20000,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 88,
"indexBounds" : {
},
"server" : "aks-osx.local:37018",
"filterSet" : false
}
Drop VM cache
sudo purge
Run query that does wider object scan than intended
db.places.find({pos: { $nearSphere: [ 0, 0 ], $maxDistance: 125}, xid: ObjectId( "547dbbe1290b9685990ca000" ), cix: 1}).explain()
{
"cursor" : "GeoSearchCursor",
"isMultiKey" : false,
"n" : 0,
"nscannedObjects" : 20000,
"nscanned" : 20000,
"nscannedObjectsAllPlans" : 20000,
"nscannedAllPlans" : 20000,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 13024,
"indexBounds" : {
},
"server" : "aks-osx.local:37018",
"filterSet" : false
}
Major - P3