c# - How does custom serializer affect searching? -

i trying use nodatime in app. app persists data in mongodb database. consider following class

public class sometype {     public objectid id { get; set; }     public instant instant { get; set; }     [bsondatetimeoptions(kind = datetimekind.local)]     public datetime datetime { get; set; }     [bsondatetimeoptions(kind = datetimekind.utc)]     public datetime datetimeutc { get; set; } //    public zoneddatetime zoneddatetime { get; set; } //    public localdatetime localdatetime { get; set; } } 

without adding custom serializer, instant property of class doesn't stored in db. reading document db fails.

public class instantbsonserializer : bsonbaseserializer {     public override object deserialize(bsonreader bsonreader, type nominaltype, ibsonserializationoptions options)     {         var ticks = bsonreader.readint64();         return new instant(ticks);     }      public override object deserialize(bsonreader bsonreader, type nominaltype, type actualtype, ibsonserializationoptions options)     {         var ticks = bsonreader.readint64();         return new instant(ticks);     }      public override void serialize(bsonwriter bsonwriter, type nominaltype, object value, ibsonserializationoptions options)     {         var instant = (instant) value;         bsonwriter.writeint64(instant.ticks);     } } 

i created above serializer , registered properly. able save , retrieve instances of class proper value set instant.

my question how c# driver handle searching using linq?

var list = mongodatabase.getcollection<sometype>("sometype")                      .asqueryable<sometype>()                      .where(x => x.instant < instant.fromdatetimeutc(datetime.touniversaltime()))                      .tolist(); console.writeline(list.count); 

i correct list of documents. i trying understand how mongodb gets data. first load data, deserialize , filter? or serialize instant value of clause , use serialized value filter documents, load matching ones , deserialize?

i tried seeing query logged mongodb profiler, doesnt seem log anything. have set profiling level 2.

in case of instant serialized value long. in case of zoneddatetime, serialized value document 2 properties. how searching work in case?

edit:

i able profiling work. following c# query,

mongodatabase.getcollection<sometype>("sometypecollection")              .asqueryable<sometype>()              .where(x => x.instant < instant.fromdatetimeutc(datetime.utcnow))              .tolist(); 

results in following mongodb query

{ "instant": { $lt: 13781017828460782 }}  

meaning, c# driver serializes instant object , uses serialized value filter results in db itself.

the driver convert linq query mongodb query , filter results before deserialising them. query not run until call tolist()

here operators supported: http://docs.mongodb.org/ecosystem/tutorial/use-linq-queries-with-csharp-driver/

the custom deserialiser not come play until driver starts building object graph data returned.

you wouldn't need custom serialiser classes simple types or you're not doing work when reading/writing docs.

if wanted control serialised, ie if class holds single datetime, why not make utc datetime stamp stored , use bsonignore other properties.