KB-2144 XOR node with multiple incoming flows hangs on second execution

Elly Meng — Mon, 17 Aug 2020 16:53:25 GMT

Current Revision posted to Appian Knowledge Base by Elly Meng on 8/17/2020 4:53:25 PM

Symptoms

When an XOR node with more than one input evaluates for the second time in a process instance, the process remains active on that node and never continues:

Cause

This is expected behavior as per the XOR gateway documentation:

"When multiple incoming flows are connected to the XOR gateway, it allows the first flow token through to an exclusive outgoing flow. Subsequent flow tokens wait for all incoming flows to arrive before executing the output flow decision."

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based on the XOR gateway logic.

Option 2

Manually edit the process instance flow according to the Action section above.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process modeler, process models, gateways, application design, processes

KB-2144 XOR node with multiple incoming flows hangs on second execution

Elly Meng — Mon, 17 Aug 2020 16:53:25 GMT

Revision 6 posted to Appian Knowledge Base by Elly Meng on 8/17/2020 4:53:25 PM

Symptoms

When an XOR node with more than one input evaluates for the second time in a process instance, the process remains active on that node and never continues:

Cause

This is expected behavior as per the XOR gateway documentation:

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based on the XOR gateway logic.

Option 2

Manually edit the process instance flow according to the Action section above.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process modeler, process models, gateways, application design, processes

DRAFT KB-[SP4664] XOR node with multiple incoming flows hangs on second execution

Elly Meng — Sun, 16 Aug 2020 02:41:06 GMT

Revision 5 posted to Appian Knowledge Base by Elly Meng on 8/16/2020 2:41:06 AM

Symptoms

When an XOR node with more than one input evaluates for the second time in a process instance, the process remains active on that node and never continues:

Cause

This is expected behavior as per the XOR gateway documentation:

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based on the XOR gateway logic.

Option 2

Manually edit the process instance flow according to the Action section above.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process modeler, process models, gateways, application design, processes

DRAFT KB-[SP4664] XOR node with multiple incoming flows hangs on second execution

Zach Puderbach — Fri, 14 Aug 2020 15:25:28 GMT

Revision 4 posted to Appian Knowledge Base by Zach Puderbach on 8/14/2020 3:25:28 PM

Symptoms

An XOR node with more than one input evaluates for the second time in a process instance, it remains active on that node and never continues:

Cause

This is expected behavior. As per the XOR gateway documentation:

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For any active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based off the XOR gateway logic.

Option 2

Manually edit the process instance flow to take the changes listed in the action step.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process models, gateways

DRAFT KB-[SP4664] XOR node with multiple incoming flows hangs on second execution

Zach Puderbach — Fri, 14 Aug 2020 15:24:46 GMT

Revision 3 posted to Appian Knowledge Base by Zach Puderbach on 8/14/2020 3:24:46 PM

Symptoms

An XOR node with more than one input evaluates for the second time in a process instance, it remains active on that node and never continues:

Cause

This is expected behavior. As per the XOR gateway documentation:

When multiple incoming flows are connected to the XOR gateway, it allows the first flow token through to an exclusive outgoing flow. Subsequent flow tokens wait for all incoming flows to arrive before executing the output flow decision.

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For any active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based off the XOR gateway logic.

Option 2

Manually edit the process instance flow to take the changes listed in the action step.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process models, gateways

DRAFT KB-[SP4664] XOR node with multiple incoming flows hangs on second execution

Zach Puderbach — Fri, 14 Aug 2020 15:24:22 GMT

Revision 2 posted to Appian Knowledge Base by Zach Puderbach on 8/14/2020 3:24:22 PM

Symptoms

An XOR node with more than one input evaluates for the second time in a process instance, it remains active on that node and never continues:

Cause

This is expected behavior. As per the XOR gateway documentation:

When multiple incoming flows are connected to the XOR gateway, it allows the first flow token through to an exclusive outgoing flow. Subsequent flow tokens wait for all incoming flows to arrive before executing the output flow decision.

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For any active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based off the XOR gateway logic.

Option 2

Manually edit the process instance flow to take the changes listed in the action step.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process models, gateways

DRAFT KB-[SP4664] XOR node with multiple incoming flows hangs on second execution

Zach Puderbach — Fri, 14 Aug 2020 15:19:01 GMT

Revision 1 posted to Appian Knowledge Base by Zach Puderbach on 8/14/2020 3:19:01 PM

Symptoms

An XOR node with more than one input evaluates for the second time in a process instance, it remains active on that node and never continues:

(Will use a more generic picture in the KB)

Cause

This is expected behavior. As per the XOR gateway documentation:

Action

For any XOR node with multiple incoming flows that is both:

Expected to execute multiple times.
Expected to evaluate after only 1 input is provided.

Modify the process model so that each incoming flow has a separate XOR node with only a single input.

Workaround

For any active process instances affected by this, there are two possible options.

Option 1

Manually start the next node that is expected to execute based off the XOR gateway logic.

Option 2

Manually edit the process instance flow to take the changes listed in the action step.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2020

Tags: process models, gateways