Finding cause of error in logs

Ignition
#1

How would I find which tag is causing the following ‘Error in Derived tag’

com.inductiveautomation.ignition.common.expressions.ExpressionException: No value found at [0, 5] in dataset

at com.inductiveautomation.ignition.common.expressions.SubscriptExpression.handleDataset(SubscriptExpression.java:168)

at com.inductiveautomation.ignition.common.expressions.SubscriptExpression.execute(SubscriptExpression.java:120)

at com.inductiveautomation.ignition.common.expressions.DefaultFunctionFactory$IsNullFunction.execute(DefaultFunctionFactory.java:557)

at com.inductiveautomation.ignition.common.expressions.FunctionExpression.execute(FunctionExpression.java:69)

at com.inductiveautomation.ignition.common.expressions.DefaultFunctionFactory$IfFunction.execute(DefaultFunctionFactory.java:2060)

at com.inductiveautomation.ignition.common.expressions.FunctionExpression.execute(FunctionExpression.java:69)

at com.inductiveautomation.ignition.gateway.tags.actors.factories.value.reference.DerivedTagValueActorFactory$DerivedTagValueActor$Executor.execute(DerivedTagValueActorFactory.java:263)

at com.inductiveautomation.ignition.gateway.tags.actors.factories.value.reference.DerivedTagValueActorFactory$DerivedTagValueActor.processIncomingValue(DerivedTagValueActorFactory.java:108)

at com.inductiveautomation.ignition.gateway.tags.actors.factories.value.reference.TagReferenceValueActorFactory$TagReferenceValueActor.tagChanged(TagReferenceValueActorFactory.java:178)

at com.inductiveautomation.ignition.gateway.tags.subscriptions.ProviderSubscriptionManagerImpl$TagChangePublish.run(ProviderSubscriptionManagerImpl.java:1365)

at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

at java.base/java.util.concurrent.FutureTask.run(Unknown Source)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

at java.base/java.lang.Thread.run(Unknown Source)

java.lang.ArrayIndexOutOfBoundsException: null

#2

First, put your error between three triple ticks to make it legible

```

my code

```

#3

Unfortunately it wont tell you exactly which tag is generating the error in the logs. However, you can narrow it down a bit.

  1. You know it is a derived tag
  2. You know it is doing some work on a dataset

If you’ve been doing any work on tags recently particularly tags which meet those two criteria, I would start there. Also, look for derived tags which have a bad quality.

In the future I would recommend wrapping expressions which can be error prone, such as lookup() in a try() expression.

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