[QUERY] Is the TableTransactionBatch intended to capture entity state?

Query/Question I am moving from WindowsAzure.Storage SDK to Azure.Data.Tables and I have many places in my code where I use a transaction entity batch to reduce round trips to Table Storage and to leverage atomic updates to many entities within a partition.

In WindowsAzure.Storage, it’s possible to built up a transaction batch and then modify the entities prior to submitting the batch and have those latest entity changes be reflected in the submitted change. In other words, this works:

1. Add entity to batch
2. Modify entity
3. Submit batch
4. See changes on step 2 in the resulting entity.

In Azure.Data.Tables, it looks like step 1 immediately captures all of the OData properties from the entity at the moment, in a deep-clone type fashion, making any changes (i.e. step 2) have no affect the batch that gets submitted.

Is this an intentional design decision? It’s certainly not an insurmountable problem. For example step 1 can actually be adding logical entity operations to a list like List<Action<TableTransactionBatch>> that I manage and then at step 3 I actually create the batch and add all of the collected operations into the batch at that time, thus capturing the latest entity state.

If this was intentional, do you think it would be worth enhancing the XML docs on the TableTransactionBatch methods to say that the current entity state is captured and future changes to the ITableEntity will not affect the batch? It caught me off guard in the migration to the new SDK so I’m wondering if others might fall into the same trouble.

Environment:

• Name and version of the Library package used: Azure.Data.Tables 12.0.0-beta.6
• Hosting platform or OS and .NET runtime version:
  • Windows 10
  • .NET 5 SDK

.NET SDK (reflecting any global.json):
Version:   5.0.201
Commit:    a09bd5c86c

Runtime Environment:
OS Name:     Windows
OS Version:  10.0.19042
OS Platform: Windows
RID:         win10-x64
Base Path:   C:\Program Files\dotnet\sdk\5.0.201\

Host (useful for support):
Version: 5.0.4
Commit:  f27d337295

.NET SDKs installed:
1.1.14 [C:\Program Files\dotnet\sdk]
2.1.814 [C:\Program Files\dotnet\sdk]
3.1.407 [C:\Program Files\dotnet\sdk]
5.0.100-dev [C:\Program Files\dotnet\sdk]
5.0.104 [C:\Program Files\dotnet\sdk]
5.0.200 [C:\Program Files\dotnet\sdk]
5.0.201 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0-preview.8.20359.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 1.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 1.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.26 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0-preview.8.20358.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0-rc.1.20366.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0-preview.8.20352.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

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• IDE and version: Visual Studio 16.10 Preview 1

[christothes]

Actually, we do show this in the samples here: https://github.com/Azure/azure-sdk-for-net/blob/master/sdk/tables/Azure.Data.Tables/samples/Sample6TransactionalBatch.md#adding-entities-with-a-transactional-batch

https://github.com/Azure/azure-sdk-for-net/blob/533ee2530f783f081d04c4bbcb79d483d9ef16a6/sdk/tables/Azure.Data.Tables/tests/samples/Sample6_TransactionalBatchAsync.cs#L74

[christothes]

Would it be your expectation for SubmitBatch to throw InvalidOperationException if it contains no operations? I think this makes sense.

I would expect that, yes. The SDK can save some unnecessary IO on a case that is likely unintended by the caller.

Cool, I’ll add an issue to make that minor change.

Is it feasible to get all of the new etags from the successful result of batch of entity updates?

Yes! Although I don’t think we have a good sample showing this yet. Example:

TableBatchResponse response = await batch.SubmitBatchAsync().ConfigureAwait(false);
// Get the new ETag for the updated entity
response.GetResponseForEntity(entity.RowKey).Headers.ETag;