[DRILL-1760] Count on a map fails with SchemaChangeException

• Type: Improvement
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.0.0
• Component/s: Functions - Drill
• Assignee: Hanifi Gunes
• Reporter: Hanifi Gunes
• Created: 20/Nov/14 19:30
• Updated: 02/Dec/15 19:56

Description

Take yelp business dataset and run

select count(attributes) from dfs.`/path/to/yelp-business.json`

you should read

org.apache.drill.exec.exception.SchemaChangeException: Failure while materializing expression. 
Error in expression at index -1.  Error: Missing function implementation: [count(MAP-REQUIRED)].  Full expression: --UNKNOWN EXPRESSION--.
	at org.apache.drill.exec.physical.impl.aggregate.StreamingAggBatch.createAggregatorInternal(StreamingAggBatch.java:221) [classes/:na]
	at org.apache.drill.exec.physical.impl.aggregate.StreamingAggBatch.createAggregator(StreamingAggBatch.java:173) [classes/:na]
	at org.apache.drill.exec.physical.impl.aggregate.StreamingAggBatch.buildSchema(StreamingAggBatch.java:89) [classes/:na]
	at org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.buildSchema(IteratorValidatorBatchIterator.java:80) [classes/:na]
	at org.apache.drill.exec.record.AbstractSingleRecordBatch.buildSchema(AbstractSingleRecordBatch.java:109) [classes/:na]
	at org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.buildSchema(IteratorValidatorBatchIterator.java:80) [classes/:na]
	at org.apache.drill.exec.physical.impl.svremover.RemovingRecordBatch.buildSchema(RemovingRecordBatch.java:64) [classes/:na]
	at org.apache.drill.exec.physical.impl.validate.IteratorValidatorBatchIterator.buildSchema(IteratorValidatorBatchIterator.java:80) [classes/:na]
	at org.apache.drill.exec.physical.impl.ScreenCreator$ScreenRoot.buildSchema(ScreenCreator.java:95) [classes/:na]
	at org.apache.drill.exec.work.fragment.FragmentExecutor.run(FragmentExecutor.java:111) [classes/:na]
	at org.apache.drill.exec.work.WorkManager$RunnableWrapper.run(WorkManager.java:249) [classes/:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_65]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_65]
	at java.lang.Thread.run(Thread.java:745) [na:1.7.0_65]

I would expect to be able run count query on `attributes` field given that I can run a select on the same field.

Issue Links

• is duplicated by: DRILL-1616 Add support for count() on maps and arrays