Start node
What it does
The Start node is where every run begins. Each canvas has exactly one. It sends no rows: it marks which nodes run first.
A new project has a Start node on the canvas. Start cannot be deleted. A saved flow that opens without one has a Start added, and you are told so.
When to use
- Always. Connect Start to each node that begins a branch of the flow, usually a Source.
- To prepare the run before any Source reads data: connect Start to a Variable, a Cache, a DB Script or a Data Profile node.
- To control the order of several Sources: connect Start to a Fork and set its Execution Order.
Configure
| Setting | What it does |
|---|---|
| When a connection's rate limit is reached | Wait up to 60 s, then fail (the default): a request waits for its turn, and the step fails if the turn is further away. Suspend and resume later: a scheduled run is marked Rescheduled and resumes from its last checkpoint. |
Suspend applies to runs started by a schedule or by Run now on a workflow job, when every source can resume. See Run performance.
What Start can connect to: Source, DB Script, Webhook Trigger, Fork, Sub-workflow, Notification, Variable, Cache and Data Profile. Other nodes read rows, and Start sends none, so put a Source first. See Flow rules.
Ports
| Port | Direction | Kind | Cardinality | Notes |
|---|---|---|---|---|
out | out | control | many | Fires once when the run starts. |
Examples
One source. Start > Source > Transform > Load.
Two independent sources. Start > Source A > Transform A > Load A, and Start > Source B > Transform B > Load B. The two branches share no node, so both Sources run at the same time.
Two sources into a Join. Start > Source A and Start > Source B, both into a Join. Sources that share a downstream node run one at a time.
Set a variable first. Start > Variable (export_name) and Start > Source > Transform > Load, where the Load path uses {{var.exec.export_name}}.
Troubleshooting
| Symptom | Cause | What to do |
|---|---|---|
| A node cannot be connected to Start | The node reads rows, and Start sends none. | Connect Start to a Source and the node after it. |
| A branch never runs | It is not connected to Start, directly or through other nodes. | Draw an edge from Start to the first node of the branch. |
| Sources run one at a time | They share a downstream node, or a Variable node is reachable from them. | No action needed. To set the order yourself, use a Fork with an Execution Order. |