Troubleshooting Siddhi Validation Errors and Exceptions

The possible exceptions relating to the validation of Siddhi queries that may occur are as follows:

No viable alternative at input (SiddhiParserException)

Sample error log	[2017-07-10 15:35:11,772] ERROR {org.wso2.carbon.event.processor.admin.EventProcessorAdminService} - Exception when validating execution plan org.wso2.siddhi.query.compiler.exception.SiddhiParserException: You have an error in your SiddhiQL at line 16:36, no viable alternative at input 'InputStream#window.time(1 min\n select
Occurrence	This occurs when validating an execution plan or when deploying an execution plan via the file system.
Possible reasons	This error indicates that there is a syntax error in your Siddhi query.
Troubleshooting options	To find the exact place in the Siddhi query where the syntax error exists, use the numbers provided (e.g., 16:36). First number indicates the line number, and second number indicates the character position.
Recommended action	Open you Siddhi query in a text editor and find the exact place using the given numbers. Then check whether you have missed any brackets, keywords, etc. The expected symbol, keyword etc. can sometimes be mentioned within the error message.

Stream definition already exists (DuplicateDefinitionException)

Sample error log	[2017-07-10 17:34:21,372] ERROR {org.wso2.carbon.event.processor.admin.EventProcessorAdminService} - Exception when validating execution plan org.wso2.carbon.event.processor.core.exception.ExecutionPlanConfigurationException: Different definition same as output stream definition :StreamDefinition{id='OutputStream', attributeList=[Attribute{id='sensor_id_distinct_count', type=DOUBLE}, Attribute{id='count', type=LONG}], annotations=[]} already exist as:StreamDefinition{id='OutputStream', attributeList=[Attribute{id='sensor_id_distinct_count', type=LONG}, Attribute{id='count', type=LONG}], annotations=[Annotation{name='Export', elements=[Element{key='null', value='org.wso2.event.temperature.statistics.stream:1.0.0'}]}]} in execution plan "SensorDataAnalysis-SensorAnalytics-ssss-realtime1"
Occurrence	This occurs when validating an execution plan or when deploying an execution plan via the file system.
Possible reasons	This exception is thrown when there are two event stream definitions with the same name and different attributes. This may have happened in one of the following ways: The two streams may have been explicitly defined with the same name. A stream you defined may have been also inferred by Siddhi.
Troubleshooting options	To find the execution plan that is causing the error, you can browse the end of the error trace log that states the execution plan name. e.g.,: `in execution plan "SensorDataAnalysis-SensorAnalytics-ssss-realtime1”` is mentioned in the sample error log given above. To find out whether both streams were explicitly defined, or whether one of them was inferred by Siddhi, you need to compare the two stream definitions printed in the log. If you read the exception carefully it prints two stream definitions within curly braces. You can extract both out and compare using a tool such as Meld and identify the issue.
Recommended action	If both the streams were explicitly defined with the same name, rename one stream. If one stream was inferred by Siddhi, you need to delete the other stream that you explicitly defined, and click Export Stream in the Create a New Execution Plan window to export the stream inferred by Siddhi to avoid mismatches. For detailed information about exporting inferred streams, see Creating a Standalone Execution Plan - Export stream.

Extension does not exist (ExecutionPlanConfigurationException)

Sample error log	[2017-07-10 18:20:13,226] ERROR {org.wso2.carbon.event.processor.admin.EventProcessorAdminService} - Exception when validating execution plan org.wso2.carbon.event.processor.core.exception.ExecutionPlanConfigurationException: test does not exist in type WindowProcessor in execution plan "SensorDataAnalysis-SensorAnalytics-ssss-realtime1" [2017-07-10 18:21:55,142] ERROR {org.wso2.carbon.event.processor.admin.EventProcessorAdminService} - Exception when validating execution plan org.wso2.carbon.event.processor.core.exception.ExecutionPlanConfigurationException: 'test' is neither a function extension nor an aggregated attribute extension in execution plan "SensorDataAnalysis-SensorAnalytics-ssss-realtime1".
Occurrence	This occurs when you implement a new extension in WSO2 DAS and try to use it.
Possible reasons	The custom extension is not properly loaded into the system.
Troubleshooting Options	Check whether the extension jar is added to the `<DAS_HOME>/repository/component/dropins` directory. Check whether the `.siddhiext file` is bundled inside the jar. This file is used to get the extension namespace and name that are used to refer to the extension. The file name is used as the extension namespace, and the identifier inside the name is used as the extension name. If both the requirements mentioned above are met, start the server with the `-DosgiConsole` argument, and check the bundle status. The bundle can be searched via the `ss` command, and the status can be queried via the `diag` command.

Cannot find attribute type (ExecutionPlanConfigurationException)

Sample error log	[2017-07-10 18:34:26,186] ERROR {org.wso2.carbon.event.processor.admin.EventProcessorAdminService} - Exception when validating execution plan org.wso2.carbon.event.processor.core.exception.ExecutionPlanConfigurationException: Cannot find attribute type as 'test' does not exist in 'InputStream'; StreamDefinition{id='InputStream', attributeList=[Attribute{id='sensor_id', type=STRING}, Attribute{id='sensor_value', type=DOUBLE}], annotations=[Annotation{name='Import', elements=[Element{key='test', value='org.wso2.event.temperature.stream:1.0.0'}]}]} in execution plan "SensorDataAnalysis-SensorAnalytics-ssss-realtime1"
Occurrence	This occurs if you try to select an attribute that does not exist via a Siddhi query.
Possible reasons	Incorrect reference to the required attribute (e.g., a mismatch in how the attribute is spelt in the stream definition and in the Siddhi query, the difference in the case used etc.)
Troubleshooting options	If stream is derived from the output of another query, check the select statement of that query to verify the attribute name. If the attribute is exposed from a `StreamProcessor` extension, verify the name with the extension implementation.