The concept of using a Buffer Source step in a flow is to retrieve data from a Buffer that was previously saved. The stored data can then be retrieved repeatedly in other flows without having to revisit the original source.

A Buffer can be likened to physical storage, be it memory or disk, and temporarily hold data while moving between processes. Typically, the data is stored in a buffer as it is retrieved from a source (i.e., a database or another web service) before it is sent to another flow or device.

To add a source step:

1. Click on the highlighted icon as shown in the below image.

2. The below page will appear. Select or search for Buffer.

Illustrated in the below image is the configuration that is available in the Buffer Source step.

The Buffer ID is the source Buffer that is used to retrieve data from in the flow. Click the dropdown to select a Buffer.

This tab is used to build a filter query to view the data in a list that matches the selected criteria, interrogate and debug the data, and search the data.

The Query Builder uses the following criteria to set up the filter:

Boolean logic to apply logical filter operations – Select an appropriate operator from AND, OR, NOT.

Rules to apply comparative operators to return records with specified data values – Select a data field, an operator, the value, and the data type in each line.

Fields tags to only display specified columns – Click on Add a tag, then type in the column name.

Order By fields to list the data in a specific order using the Order By operator.

Skip to omit the first n number of records as specified.

The Raw Query option is used to examine the filter query with the comparative operators displayed in MongoDB Query Language.

Read about other Source Steps

Revisit the Getting Started page for a refresher.

Read more about Flow Steps here.

Read more about Buffers here.