[SYSTEMDS-3482] Parallel Hadoop IO Startup

I observed that the compile time if we include IO operations increase to
~0.6 sec. While if we do not have IO operations it is ~0.2 sec. This
is due to the hadoop IO we are using taking up to 70% of the compile time
in cases where we have simple scripts with only read and a single operation.
This is a constant overhead on the fist IO operation that does not effect
subsequent IO operations, to improve this I have moved this to a parallel
operation when we construct the JobConfiguration. This improve the
compile time of systemds in general from ~0.6 sec when using IO to ~0.2 sec.

Closes #1757

src/main/java/org/apache/sysds/conf/ConfigurationManager.java

@@ -19,20 +19,28 @@
 
 package org.apache.sysds.conf;
 
+import java.util.concurrent.ExecutorService;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.mapred.JobConf;
 import org.apache.sysds.conf.CompilerConfig.ConfigType;
 import org.apache.sysds.hops.OptimizerUtils;
 import org.apache.sysds.lops.Compression.CompressConfig;
 import org.apache.sysds.lops.compile.linearization.ILinearize;
+import org.apache.sysds.runtime.controlprogram.parfor.stat.InfrastructureAnalyzer;
+import org.apache.sysds.runtime.io.IOUtilFunctions;
+import org.apache.sysds.runtime.util.CommonThreadPool;
 
 /**
  * Singleton for accessing the parsed and merged system configuration.
  * 
  * NOTE: parallel execution of multiple DML scripts (in the same JVM) with different configurations  
  *       would require changes/extensions of this class. 
  */
-public class ConfigurationManager
-{
+public class ConfigurationManager{
+	private static final Log LOG = LogFactory.getLog(ConfigurationManager.class.getName());
+
 	/** Global cached job conf for read-only operations */
 	private static JobConf _rJob = null; 
 
@@ -56,6 +64,17 @@ public class ConfigurationManager
 		//ConfigManager -> OptimizerUtils -> InfrastructureAnalyer -> ConfigManager 
  		_dmlconf = new DMLConfig();
 		_cconf = new CompilerConfig();
+
+		final ExecutorService pool = CommonThreadPool.get(InfrastructureAnalyzer.getLocalParallelism());
+		pool.submit(() ->{
+			try{
+				IOUtilFunctions.getFileSystem(_rJob);
+			}
+			catch(Exception e){
+				LOG.warn(e.getMessage());
+			}
+		});
+		pool.shutdown();
 	}