[jira] [Commented] (IGNITE-12824) Interoperable Ignite.NET Dates

["Alexey Kukushkin (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-12824?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17225675#comment-17225675 ] 

Alexey Kukushkin commented on IGNITE-12824:
-------------------------------------------

Extended the ticket scope. Removed the old patch, working on the new one.

> Interoperable Ignite.NET Dates
> ------------------------------
>
>                 Key: IGNITE-12824
>                 URL: https://issues.apache.org/jira/browse/IGNITE-12824
>             Project: Ignite
>          Issue Type: Improvement
>          Components: platforms
>    Affects Versions: 2.8
>            Reporter: Alexey Kukushkin
>            Assignee: Alexey Kukushkin
>            Priority: Major
>              Labels: .NET, ignite-3, sbcf
>             Fix For: 3.0
>
>
> *+The Problem+* 
>  Presently .NET API writes dates as composite Ignite objects. Only .NET clients can read such dates: any other client (JDBC, Java, etc) does not understand it without custom deserialization.
>   
>  It is still possible to configure .NET serialization to write dates as Ignite dates - see [DateTime Serialization note|https://ignite.apache.org/docs/latest/net-specific/net-platform-interoperability#types-compatibility]. But then Ignite accepts only UTC dates, requiring the application developers to convert local dates to UTC dates and back. This task is not trivial: [DateTime.ToUniversalTime|https://docs.microsoft.com/en-us/dotnet/api/system.datetime.touniversaltime?view=netcore-3.1] uses calendars different from Java (and the .NET calendars are the invalid ones - especially for pre-1990 dates).
>   
>  The motivation for the current default behavior was probably the desire to keep the Time Zone information: Ignite dates do not store time zones.
>   
>  In our experience interoperability is more important than storing time zone info.
>   
>  *+The Solution+*
>  # Always write .NET dates as portable Ignite dates: get rid of the {{BinaryReflectiveSerializer.ForceTimestamp}} flag that currently triggers this behavior. 
> Keep the {{ForceTimestamp}} flag if saving .NET dates as transparent objects seems a useful case.
>  # Automatically convert Local dates to UTC and back *inside* Ignite.NET. 
> Add a {{UtcDate}} date flag to {{QuerySqlFieldAttribute}} and {{BinaryReflectiveSerializer}} to control the deserialization behavior to prevent loosing the {{DateTime.Kind}} property of UTC dates.
>  # Use [NodaTime|https://nodatime.org/] for UTC<->Local conversions. Noda time uses Java calendars making the conversion truly portable.
>  
> *+The Benefits+*
>  # Portable dates is a more frequent use-case than storing time zone info for every date in Ignite. This becomes default behavior and the developers do not need to always explicitly configure it.
>  # Non-trivial code to make the truly portable UTC<->Local conversion is implemented once inside Ignite instead of having every Ignite.NET application implementing it.



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