Joins

An interval join is available in Event Processing.

Interval join

An interval join is used to merge two event streams based on a join condition that matches events within a time period.

Adding an interval join node

To add an interval join, complete the following steps.

1. Ensure that a stream of events is available, from an Event Source node or from the output of any previously configured node.
2. In the Palette, under Joins, drag the Interval join node into the canvas.
3. Connect the node to two event sources by separately dragging the Output Port from each source node into the Input Port of this node.
4. Hover over the node and click Edit to configure the node.

The Configure Interval join window is displayed.

Configuring an interval join node

To configure an interval join, complete the following steps.

Details

In the Details section, enter a name for your node. The output stream of events from this node will be referred with the name you entered.

Join condition

To define your join condition, on the Join condition section, in the Define events text box, enter your expression.

Alternatively, you can use the assistant to create your expression.

1. Click the Assistant drop-down menu to open the assistant.
2. In the Specify property from [name of the first event source] drop-down menu, select the property that you want to match.
3. In the Specify property from [name of the second event source] drop-down menu, select a property to match the one chosen in step 2.
4. Click Add to expression to insert the expression into the text-box.

Note: Ensure that the property you choose for both sides of your expression has the same data type.

Time window condition

To define the time window condition, complete the following steps.

1. In the Event to detect drop-down menu, select the property of the event you are interested in.
2. In the Event to set the time window drop-down menu, select the property of an event used to define the time window.
3. In the Offset from event to start the time window field, input an integer value and select the corresponding time unit. Then input another integer in the Offset from event to end the time window field to define the duration of the time window.

Note: Ensure that the end-time of the time window is later than the start-time.

Output properties

You can manage the properties that come from this node to suit your requirements.

Rename a property

To rename a property, complete the following steps.

1. Hover over the property name and click the Edit icon .
2. In the text-box, enter a new name for your property.
3. Click outside the text-box or press Enter on your keyboard to rename the property.

Properties to remove

To remove a property from being displayed in the output, click the Remove property icon .

Note: Take extreme care in removing an event time property. By keeping an event time property, you can propagate the event time to downstream nodes on the canvas. The event time property is necessary for time-based calculations in nodes, such as aggregate or another interval join.

Add a removed property

To add a property that was previously removed, complete the following steps.

1. Go to the Properties to remove table that lists the removed properties.
2. In the row of the property that you want to restore, click the Add icon .

After you have set up the interval join node, click Configure.

A green checkbox appears on the interval join node if the interval join node is configured correctly. If there is any error in your configuration, a red checkbox appears.

User actions are saved automatically. For save status updates, see the canvas header.

• Saving indicates that saving is in progress.
• Saved confirms success.
• Failed indicates that there are errors. If an action fails to save automatically, you receive a notification to try the save again. Click Retry to re-attempt the save. When a valid flow is saved, you can proceed to run the job.

If you are running versions earlier than 1.0.5, click Save in the navigation banner to save the flow.