5.0 RC4 - Scalar mappings are storing Decimal as double

[niemyjski]

I noticed an issue where you can't round trip Decimal.MaxValue as the mapping type is double. This occurs due to an overflow (Value was either too large or too small for a Decimal.). It might be good to have unit tests for all the c# numeric types and do max value of each type and then call AutoMap / Scalar and then attempt to round trip them. As precision will be lost or gained and it should be handled :).

The following snippet shows off what's happening in the simplest of terms (http://stackoverflow.com/questions/21337241/convert-from-decimal-to-single-and-back-why-does-it-throw-an-overflow-exception).

double dbl = (double)Decimal.MaxValue;
decimal dec = (decimal)dbl;

I think this has to due with two things that should be noted. The types supported by elastic don't always match up to .NET Types and serialization.

[russcam]

related elastic/elasticsearch#17006

[russcam]

We discussed earlier this week about what we can or should do regarding this.

We decided that we would document the usage of decimal POCO property types in the automapping documentation (I think a separate section on types would be better in the future; I'll add an item to #2248) and how these map to Elasticsearch's double type. Attempting to handle an overflow exception in the client seems disingenuous, even if it originates from a Decimal.MinValue or Decimal.MaxValue conversion to double.

Hope that makes sense.

[niemyjski]

Yeah, I'm not sure, but I can tell you I would't read the xml docs for to see the conversion warning and I don't use auto mapping. I'd just expect it to work. I totally understand why it doesn't, but will other developers.