FHIR Chat · serialization performance

Stream: dotnet

Topic: serialization performance

Michele Mottini (Oct 30 2019 at 23:25):

I am doing some performance testing and it takes 2 / 3 msec to serialize a 13 KB bundle containing 3 patients - that seems pretty slow. Is this the expected performance? Or maybe I am doing something wrong...

Brian Postlethwaite (Oct 30 2019 at 23:30):

The string or stream serializer?

Brian Postlethwaite (Oct 30 2019 at 23:32):

In my server I've gone to the stream serializer to reduce string allocations and garbage collection.

Brian Postlethwaite (Oct 30 2019 at 23:32):

On a single instance not so significant, but for a server it all adds up.

Christiaan Knaap (Oct 31 2019 at 13:20):

Are you serializing from a POCO or an ITypedElement?

Michele Mottini (Oct 31 2019 at 13:57):

Serializing from a POCO to string

Michele Mottini (Oct 31 2019 at 13:59):

            var xml = File.ReadAllText(@"c:\temp\bundle.xml");

            var xmlParser = new FhirSerialization.FhirXmlParser(FhirModel.Version.DSTU2);
            var bundle = xmlParser.Parse<FhirModel2.Bundle>(xml);
            var watch = Stopwatch.StartNew();
            bundle = xmlParser.Parse<FhirModel2.Bundle>(xml);
            watch.Stop();
            Console.WriteLine("Parse: {0}ms", watch.ElapsedMilliseconds);

            var xmlSerializer = new FhirSerialization.FhirXmlSerializer(FhirModel.Version.DSTU2);
            var bundleXml = xmlSerializer.SerializeToString(bundle);
            watch.Restart();
            const int count = 10;
            for (var i=0; i<count; i++)
            {
                xmlSerializer = new FhirSerialization.FhirXmlSerializer(FhirModel.Version.DSTU2);
                bundleXml = xmlSerializer.SerializeToString(bundle);
            }
            watch.Stop();
            Console.WriteLine("Serialize x {1}: {0}ms", watch.ElapsedMilliseconds, count);

Brian Postlethwaite (Oct 31 2019 at 20:04):

Also assuming this is not the first time when it leads in all the reflection stuff?
The first one is always considerably longer.
Looking at the code I think it's outside your timer.

Michele Mottini (Oct 31 2019 at 20:45):

Not the first one - first one takes multiple seconds

Michele Mottini (Oct 31 2019 at 21:21):

3 msec to serialize 13 KB is not thumbs up...

Brian Postlethwaite (Nov 01 2019 at 11:14):

I agree with that for sure. Was confirming what you're seeing.

Michele Mottini (Nov 01 2019 at 13:47):

Thanks Brian - I wanted confirmation that was not something specific to our fork of the library

Michele Mottini (Nov 08 2019 at 03:46):

I did an experiment of writing a trivial serializer for a bundle of patients to get a baseline speed:

Serialize X 1,000: 3,275.0ms
New serialize X 1,000: 123.0ms

Michele Mottini (Nov 08 2019 at 03:49):

Code is something like this:

        public void Serialize(JsonWriter writer)
        {
            writer.WriteStartObject();
            writer.WritePropertyName("resourceType"); writer.WriteValue("Bundle");
            writer.WritePropertyName("type"); writer.WriteValue(TypeElement.ObjectValue);
            writer.WritePropertyName("total"); writer.WriteValue(TotalElement.ObjectValue);
            writer.WritePropertyName("link");
            writer.WriteStartArray();
            foreach(var link in Link)
            {
                link.Serialize(writer);
            }
            writer.WriteEndArray();
            writer.WritePropertyName("entry");
            writer.WriteStartArray();
            foreach (var entry in Entry)
            {
                entry.Serialize(writer);
            }
            writer.WriteEndArray();
            writer.WriteEndObject();
        }

and so on down for the various classes