Block Until Done tool icon

Block Until Done Tool

Last modified: September 09, 2021

Docs are available before the release of Designer Cloud so you can get a sneak peek. This content might change between now and the official release.

One Tool Example

Block until Done has a One Tool Example. Visit Sample Workflows to learn how to access this and many other examples directly in Alteryx Designer Cloud.

Use Block until Done to stop datasets from moving downstream until the last row in the set has been processed by all previous tools. In addition, this tool makes sure that only a single output stream at a time receives the completed dataset. Subsequent streams are blocked until all the dataset rows are pushed through the 1st stream.

You can use the tool in these scenarios:

  • When reading and writing to the same file, use the Block until Done tool to make sure the entire file is read before being written to.
  • When writing to an Excel file, you can use the tool to write only to 1 sheet at a time, preventing write errors.

Keep in mind that the Block Until Done tool can slow down execution because it requires a large amount of memory.

Tool Components


The Block until Done tool has 4 anchors. 

  • Input anchor: Use the input anchor to select the incoming dataset.
  • 1 output anchor: The 1 anchor executes 1st.
  • 2 output anchor: The 2 anchor executes 2nd.
  • 3 output anchor: The 3 anchor executes 3rd.

Configure the Tool

You don't need to configure the Block until Done tool. Place the tool at the workflow location where you want to sequence downstream data processing. The workflow executes the datasets in the order defined by the Block until Done tool's output anchors.

Troubleshoot Data Stream Sequence

When 2 or more Block Until Done tools are on the canvas, Designer Cloud has to decide which data stream to run.

  1. Designer Cloud determines the order in which each tool was added to the workflow using the tool's Tool ID.
  2. Designer Cloud runs the data stream that contains the tool that was added 1st.

If data streams aren't running in the order you expect, check the Tool IDs of the tools upstream from the Block until Done tool. To check Tool ID:

  1. Select the tool.
  2. In the Configuration window, see what number is assigned to the tool. This number indicates the order in which the tool was added to the workflow.

Separate Stream Example

An Input Data tool (ID 1) and a Text Input tool (ID 2) are placed on the canvas. Each input is connected to a Block until Done tool. The data stream with the Input Data tool runs 1st, regardless of which Block until Done tool it is connected to because its ID indicates that it was placed first.

Shared Stream Example

An Input Data tool (ID 1) is connected to a Formula tool (ID 2) and a Filter tool (ID 3). Both the Formula and Filter tools are connected to Block until Done tools. The Formula tool's ID is compared to the Filter tool's ID because they are the farthest upstream tools that are not shared by the Block until Done tools. The data stream with the Formula tool runs 1st because its ID indicates that it was placed before the Filter tool.

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