Make Microsoft.Data.Sqlite unloadable

[GabrieleGervasiPEL]

Description:
Unable to unload AssemblyLoadContext after creating a Microsoft.Data.Sqlite.SqliteConnection

Reproduction Steps:

1. Take the unloading solution from https://github.com/dotnet/samples/tree/main/core/tutorials/Unloading
2. Upgrade the solution targeting Net6.0
3. Add EnableDynamicLoading at true in Plugin.csproj
4. Implement LoadUnmanagedDll to HostAssemblyLoadContext
5. Add nuget reference to Microsoft.Data.Sqlite 6.0.2 in project Plugin
6. In PluginClass constructor add: using var connection = new Microsoft.Data.Sqlite.SqliteConnection();
7. All those steps are already implemented in zipped project

Unloading_MicrosoftDataSqlite.zip

Microsoft.Data.Sqlite version: 6.0.2
Target framework: Net 6.0
Operating system: Windows 10

Could be related with dotnet/runtime#65781

[GabrieleGervasiPEL]

Temporarely 'solved' the problem compiling my own version and:

• Removing from SqliteConnectionFactory constructor AppDomain.CurrentDomain.DomainUnload and AppDomain.CurrentDomain.ProcessExit. They seems to block unloading when registered.
• Calling a custom method on SqliteConnectionFactory that call ClearPools() and _pruneTimer.Dispose() to unload

[ajcvickers]

Note from triage: We could unhook the events. etc. when calling ClearAllPools, and then re-register them again when the first new connection is made.

[progsung]

Another solution : Add Pooling=False to sqlite connectionStrings.

ref=>

https://docs.microsoft.com/en-us/dotnet/standard/data/sqlite/connection-strings