public void releaseExecutionMemory(long size, MemoryMode mode, MemoryConsumer consumer) {
        logger.debug("Task {} release {} from {}", taskAttemptId, Utils.bytesToString(size), consumer);
        memoryManager.releaseMemory(size, taskAttemptId);
    }
Release N bytes of execution memory for a MemoryConsumer.
indexr-query-opt/src/main/java/org/apache/spark/memory/TaskMemoryManager.java