Concurrency check is missing in Updates

[DevInstinct]

This is a duplicate of #209, which has been unfortunately closed.

Entity Framework generates a WHERE close on updates to check concurrent updates for each entity that has a concurrency token (timestamp). The bulk updates don't generate those WHERE clauses and skip EF concurrency checks.

Any plan to add support for concurrency checks?

[borisdj]

Will consider it.
So when concurrency conflict is found the operation should abort?

[DevInstinct]

My suggestion would be that the operation should throw a concurrency exception.

[borisdj]

Support added with latest version 3.4.7+.
For BulkUpdate set
bulkConfig = new BulkConfig { SetOutputIdentity = true, DoNotUpdateIfTimeStampChanged = true };
It works in a way that those rows with concurrency conflict, meaning TimeStamp column is changed since read, will not be updated and their entities will be loaded into BulkConfig in TimeStampInfo object with properties:
{ int NumberOfSkippedForUpdate, List<object> EntitiesOutput }
After reading them, depending on our need, we can either leave them skipped, update them again, throw exception or even rollback entire Update.
Example in the Test:

EFCore.BulkExtensions/EFCore.BulkExtensions.Tests/EFCoreBulkTestAtypical.cs

Lines 57 to 103 in f867620

	private void TimeStampTest(DbServer databaseType)
	{
	ContextUtil.DbServer = databaseType;
	using (var context = new TestContext(ContextUtil.GetOptions()))
	{
	context.Truncate<File>();
	var entities = new List<File>();
	for (int i = 1; i <= EntitiesNumber; i++)
	{
	var entity = new File
	{
	Data = "Some data " + i
	};
	entities.Add(entity);
	}
	context.BulkInsert(entities, bulkAction => bulkAction.SetOutputIdentity = true); // example of setting BulkConfig with Action argument
	// For testing concurrency conflict (UPDATE changes RowVersion which is TimeStamp column)
	context.Database.ExecuteSqlRaw("UPDATE dbo.[File] SET Data = 'Some data 1 PRE CHANGE' WHERE [Id] = 1;");
	var entitiesToUpdate = entities.Take(10).ToList();
	foreach (var entityToUpdate in entitiesToUpdate)
	{
	entityToUpdate.Data += " UPDATED";
	}
	using (var transaction = context.Database.BeginTransaction())
	{
	var bulkConfig = new BulkConfig { SetOutputIdentity = true, DoNotUpdateIfTimeStampChanged = true };
	context.BulkUpdate(entitiesToUpdate, bulkConfig);
	var list = bulkConfig.TimeStampInfo?.EntitiesOutput.Cast<File>().ToList();
	Assert.Equal(9, list.Count());
	Assert.Equal(1, bulkConfig.TimeStampInfo.NumberOfSkippedForUpdate);
	if (bulkConfig.TimeStampInfo?.NumberOfSkippedForUpdate > 0)
	{
	transaction.Rollback();
	}
	else
	{
	transaction.Commit();
	}
	}
	}
	}

[defunky]

@borisdj I can't seem to get this to work (I'm using upsert), TimeStampInfo seems to always be null. I've defined the RowVersion as RowVersion type in the table? Does the library support optimistic locking via ConcurrencyCheck attribute as well?

[oresttkachukd]

Tried both, always receive TimeStampInfo to be null:

• type: "timestamp", rowVersion: true, nullable: false
• type: "rowversion", rowVersion: true, nullable: false

[oresttkachukd]

@defunky in case it is still valid - adding SetOutputIdentity = true fixes the issue