Manish Gupta created CARBONDATA-2143:
----------------------------------------
Summary: Fixed query memory leak issue for task failure during
initialization of record reader
Key: CARBONDATA-2143
URL: https://issues.apache.org/jira/browse/CARBONDATA-2143
Project: CarbonData
Issue Type: Bug
Reporter: Manish Gupta
Assignee: Manish Gupta
**Problem:**
Whenever a query is executed, in the internalCompute method of CarbonScanRdd
class record reader is initialized. A task completion listener is attached to
each task after initialization of the record reader.
During record reader initialization, queryResultIterator is initialized and one
blocklet is processed. The blocklet processed will use available unsafe memory.
Lets say there are 100 columns and 80 columns get the space but there is no
space left for the remaining columns to be stored in the unsafe memory. This
will result is memory exception and record reader initialization will fail
leading to failure in query.
In the above case the unsafe memory allocated for 80 columns will not be freed
and will always remain occupied till the JVM process persists.
**Impact**
It is memory leak in the system and can lead to query failures for queries
executed after one one query fails due to the above reason.
*Exception Trace*
java.lang.RuntimeException: java.util.concurrent.ExecutionException:
java.lang.RuntimeException: java.lang.RuntimeException:
org.apache.carbondata.core.memory.MemoryException: Not enough memory
at
org.apache.carbondata.core.scan.processor.AbstractDataBlockIterator.updateScanner(AbstractDataBlockIterator.java:136)
at
org.apache.carbondata.core.scan.processor.impl.DataBlockIteratorImpl.next(DataBlockIteratorImpl.java:50)
at
org.apache.carbondata.core.scan.processor.impl.DataBlockIteratorImpl.next(DataBlockIteratorImpl.java:32)
at
org.apache.carbondata.core.scan.result.iterator.DetailQueryResultIterator.getBatchResult(DetailQueryResultIterator.java:49)
at
org.apache.carbondata.core.scan.result.iterator.DetailQueryResultIterator.next(DetailQueryResultIterator.java:41)
at
org.apache.carbondata.core.scan.result.iterator.DetailQueryResultIterator.next(DetailQueryResultIterator.java:31)
at
org.apache.carbondata.core.scan.result.iterator.ChunkRowIterator.<init>(ChunkRowIterator.java:41)
at
org.apache.carbondata.hadoop.CarbonRecordReader.initialize(CarbonRecordReader.java:84)
at
org.apache.carbondata.spark.rdd.CarbonScanRDD.internalCompute(CarbonScanRDD.scala:378)
at
org.apache.carbondata.spark.rdd.CarbonRDD.compute(CarbonRDD.scala:60)
at
org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at
org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at
org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at
org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at
org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:324)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:288)
at
org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
at org.apache.spark.scheduler.Task.run(Task.scala:99)
at
org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
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