Hello,

I am using MongoDB to store at the moment 100,000 documents. Each document can have from 1 to 150 properties. I need to search by property range for any combination of properties. On average a document has 5 properties set. Here is for example 2 documents, the first has properties 1, 2 and 17 set and doc2 has properties 1, 3 and 45.

doc1 =

{prop1: 123.1, prop2: 345.2, prop17: 12.0}

doc2 =

{prop1: 124.1, prop3: 33455.2, prop45: 11232.0}

The kind of queries needed are:

db.collection.find({prop1: {$gt: 123.0, $lt: 250.0}, prop3: {$gt: 10.0}});

It is not possible to create 150 indexes, one for each property, so Mathias (mstearn) suggested to store the properties this way with a single index on p:

doc1 = {p: [

{prop1: 123.1}

,

{prop2: 345.2}

,

{prop17: 12.0}

]}
doc2 = {p: [

{prop1: 124.1}

,

{prop3: 33455.2}

,

{prop45: 11232.0}

]}

And to query this way:

db.testarray.find({"p": {$elemMatch: {prop1: {$gt: 123.0, $lt: 250.0}, prop3: {$gt: 10.0}}}});

But in that case, the index on p is not used and the complete collection is scanned.

See the attached javascript setting up a small 10000 document collection with some test data.