RavenDB facet takes to long query time - ravendb

Question

I am new to ravendb and trying it out to see if it can do the job for the company i work for .
i updated a data of 10K records to the server .
each data looks like this :
{
"ModelID": 371300,
"Name": "6310I",
"Image": "0/7/4/9/28599470c",
"MinPrice": 200.0,
"MaxPrice": 400.0,
"StoreAmounts": 4,
"AuctionAmounts": 0,
"Popolarity": 16,
"ViewScore": 0.0,
"ReviewAmount": 4,
"ReviewScore": 40,
"Cat": "E-Cellphone",
"CatID": 1100,
"IsModel": true,
"ParamsList": [
{
"ModelID": 371300,
"Pid": 188396,
"IntVal": 188402,
"Param": "Nokia",
"Name": "Manufacturer",
"Unit": "",
"UnitDir": "left",
"PrOrder": 0,
"IsModelPage": true
},
{
"ModelID": 371305,
"Pid": 398331,
"IntVal": 1559552,
"Param": "1.6",
"Name": "Screen size",
"Unit": "inch",
"UnitDir": "left",
"PrOrder": 1,
"IsModelPage": false
},.....
where ParamsList is an array of all the attributes of a single product.
after building an index of :
from doc in docs.FastModels
from docParamsListItem in ((IEnumerable<dynamic>)doc.ParamsList).DefaultIfEmpty()
select new { Param = docParamsListItem.IntVal, Cat = doc.Cat }
and a facet of
var facetSetupDoc = new FacetSetup
{
Id = "facets/Params2Facets",
Facets = new List<Facet> { new Facet { Name = "Param" } }
};
and search like this
var facetResults = session.Query<FastModel>("ParamNewIndex")
.Where(x => x.Cat == "e-cellphone")
.ToFacets("facets/Params2Facets");
it takes more than a second to query and that is on only 10K of data . where our company has more than 1M products in DB.
am i doing something wrong ?

Answer 1

In order to generate facets, you have to check for each & every individual value of docParamsListItem.IntVal. If you have a lot of them, that can take some time.
In general, you shouldn't have a lot of facets, since that make no sense, it doesn't help the user.
For integers, you usually use ranges, instead of the actual values.
For example, price within a certain range.
You use just the field for things like manufacturer, or the MegaPixels count, where you have lot number or items (about a dozen or two)
You didn't mention which build you are using, but we made some major improvements there recently.