DB2 CONNECT / DB2CONNCT / B50 - DB2

When Application performs DML operation on a Large batch of
statements using IBM Entity Framework Core driver, following
error can occur:

System.ArgumentException: An item with the same key has already
been added. Key: p98
at System.Collections.Generic.Dictionary`2.TryInsert(TKey key,
TValue value, InsertionBehavior behavior)
at
Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBa
tch.CreateStoreCommand()
at
Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBa
tch.ExecuteAsync(IRelationalConnection connection,
CancellationToken cancellationToken)
at
IBM.EntityFrameworkCore.Update.Internal.Db2BatchExecutor.Execute
Async(IEnumerable`1 commandBatches, IRelationalConnection
connection, CancellationToken cancellationToken)
at
IBM.EntityFrameworkCore.Update.Internal.Db2BatchExecutor.Execute
Async(IEnumerable`1 commandBatches, IRelationalConnection
connection, CancellationToken cancellationToken)
at
IBM.EntityFrameworkCore.Update.Internal.Db2BatchExecutor.Execute
Async(IEnumerable`1 commandBatches, IRelationalConnection
connection, CancellationToken cancellationToken)
at
Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManag
er.SaveChangesAsync(IList`1 entriesToSave, CancellationToken
cancellationToken)
at
Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManag
er.SaveChangesAsync(DbContext _, Boolean
acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at
Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean
acceptAllChangesOnSuccess, CancellationToken cancellationToken)
System.ArgumentException: An item with the same key has already
been added. Key: p98
at System.Collections.Generic.Dictionary`2.TryInsert(TKey key,
TValue value, InsertionBehavior behavior) at
Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBa
tch.CreateStoreCommand()
at
Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBa
tch.ExecuteAsync(IRelationalConnection connection,
CancellationToken cancellationToken)
at
IBM.EntityFrameworkCore.Update.Internal.Db2BatchExecutor.Execute
Async(IEnumerable`1 commandBatches, IRelationalConnection
connection, CancellationToken cancellationToken)
at
IBM.EntityFrameworkCore.Update.Internal.Db2BatchExecutor.Execute
Async(IEnumerable`1 commandBatches, IRelationalConnection
connection, CancellationToken cancellationToken)
at
IBM.EntityFrameworkCore.Update.Internal.Db2BatchExecutor.Execute
Async(IEnumerable`1 commandBatches, IRelationalConnection
connection, CancellationToken cancellationToken)
at
Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManag
er.SaveChangesAsync(IList`1 entriesToSave, CancellationToken
cancellationToken)
at
Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManag
er.SaveChangesAsync(DbContext _, Boolean
acceptAllChangesOnSuccess, CancellationToken cancellationToken)
at
Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean
acceptAllChangesOnSuccess, CancellationToken cancellationToken)

****************************************************************
* USERS AFFECTED:                                              *
* DB2 Connect .NET EF Core 5.0 users                           *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to IBM Entity Framework Core Provider version        *
* 5.0.0.500 NuGet package                                      *
* NuGet packages are located:                                  *
* https://www.nuget.org/packages/IBM.EntityFrameworkCore/5.0.0 *
* .500                                                         *
* https://www.nuget.org/packages/IBM.EntityFrameworkCore-lnx/5 *
* .0.0.500                                                     *
* https://www.nuget.org/packages/IBM.EntityFrameworkCore-osx/5 *
* .0.0.500                                                     *
****************************************************************

Configure MaxBatchSize to 42.
For example :

options.UseDb2(, p =>
{ p.SetServerInfo(, );
p.MaxBatchSize(42); }))

****************************************************************
* USERS AFFECTED:                                              *
* DB2 Connect .NET EF Core 5.0 users                           *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to IBM Entity Framework Core Provider version        *
* 5.0.0.500 NuGet package                                      *
* NuGet packages are located:                                  *
* https://www.nuget.org/packages/IBM.EntityFrameworkCore/5.0.0 *
* .500                                                         *
* https://www.nuget.org/packages/IBM.EntityFrameworkCore-lnx/5 *
* .0.0.500                                                     *
* https://www.nuget.org/packages/IBM.EntityFrameworkCore-osx/5 *
* .0.0.500                                                     *
****************************************************************

Problem fixed in IBM Entity Framework Core Provider  and will be
available on NuGet via version 5.0.0.500.

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

26.10.2021
10.01.2022
24.10.2022