@Override
      public CacheRuntimeException createCancellationException(final long timeLimitMillis,
          final ExecutionContext executionContext) {
        return new QueryExecutionLowMemoryException(
            String.format(
                "Query execution canceled due to memory threshold crossed in system, memory used: %s bytes.",
                memoryUsedBytes));
      }
Run all cancelation tasks. Leave the executor's task queue empty.
geode-core/src/main/java/org/apache/geode/cache/query/internal/QueryMonitor.java