HBASE-16221 Have ThriftScanner update the ConnectionCache's last used time overtime getScannerRow() to keep the connection alive for long lived scanners

Signed-off-by: Elliott Clark <eclark@apache.org>

hbase-server/src/main/java/org/apache/hadoop/hbase/util/ConnectionCache.java

@@ -189,6 +189,20 @@ public class ConnectionCache {
     return connInfo;
   }
 
+  /**
+   * Updates the access time for the current connection. Used to keep Connections alive for
+   * long-lived scanners.
+   * @return whether we successfully updated the last access time
+   */
+  public boolean updateConnectionAccessTime() {
+    String userName = getEffectiveUser();
+    ConnectionInfo connInfo = connections.get(userName);
+    if (connInfo != null) {
+      return connInfo.updateAccessTime();
+    }
+    return false;
+  }
+
   class ConnectionInfo {
     final Connection connection;
     final String userName;

hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/ThriftHBaseServiceHandler.java

@@ -383,8 +383,8 @@ public class ThriftHBaseServiceHandler implements THBaseService.Iface {
       ex.setMessage("Invalid scanner Id");
       throw ex;
     }
-
     try {
+      connectionCache.updateConnectionAccessTime();
       return resultsFromHBase(scanner.next(numRows));
     } catch (IOException e) {
       throw getTIOError(e);

hbase-thrift/src/test/java/org/apache/hadoop/hbase/thrift2/TestThriftHBaseServiceHandler.java

@@ -589,6 +589,57 @@ public class TestThriftHBaseServiceHandler {
     }
   }
 
+  /**
+   * Tests keeping a HBase scanner alive for long periods of time. Each call to getScannerRow()
+   * should reset the ConnectionCache timeout for the scanner's connection
+   * @throws Exception
+   */
+  @Test
+  public void testLongLivedScan() throws Exception {
+    int numTrials = 6;
+    int trialPause = 1000;
+    int cleanUpInterval = 100;
+    Configuration conf = new Configuration(UTIL.getConfiguration());
+    // Set the ConnectionCache timeout to trigger halfway through the trials
+    conf.setInt(ThriftHBaseServiceHandler.MAX_IDLETIME, (numTrials / 2) * trialPause);
+    conf.setInt(ThriftHBaseServiceHandler.CLEANUP_INTERVAL, cleanUpInterval);
+    ThriftHBaseServiceHandler handler = new ThriftHBaseServiceHandler(conf,
+        UserProvider.instantiate(conf));
+
+    ByteBuffer table = wrap(tableAname);
+    // insert data
+    TColumnValue columnValue = new TColumnValue(wrap(familyAname), wrap(qualifierAname),
+        wrap(valueAname));
+    List<TColumnValue> columnValues = new ArrayList<TColumnValue>();
+    columnValues.add(columnValue);
+    for (int i = 0; i < numTrials; i++) {
+      TPut put = new TPut(wrap(("testScan" + i).getBytes()), columnValues);
+      handler.put(table, put);
+    }
+
+    // create scan instance
+    TScan scan = new TScan();
+    List<TColumn> columns = new ArrayList<TColumn>();
+    TColumn column = new TColumn();
+    column.setFamily(familyAname);
+    column.setQualifier(qualifierAname);
+    columns.add(column);
+    scan.setColumns(columns);
+    scan.setStartRow("testScan".getBytes());
+    scan.setStopRow("testScan\uffff".getBytes());
+    // Prevent the scanner from caching results
+    scan.setCaching(1);
+
+    // get scanner and rows
+    int scanId = handler.openScanner(table, scan);
+    for (int i = 0; i < numTrials; i++) {
+      // Make sure that the Scanner doesn't throw an exception after the ConnectionCache timeout
+      List<TResult> results = handler.getScannerRows(scanId, 1);
+      assertArrayEquals(("testScan" + i).getBytes(), results.get(0).getRow());
+      Thread.sleep(trialPause);
+    }
+  }
+
   @Test
   public void testReverseScan() throws Exception {
     ThriftHBaseServiceHandler handler = createHandler();