[LENS-1545]: Fixed Bug in Prepared Query.

lens-driver-jdbc/src/main/java/org/apache/lens/driver/jdbc/JDBCDriver.java

@@ -633,14 +633,7 @@ public void validate(AbstractQueryContext pContext) throws LensException {
       PreparedStatement stmt;
       // Estimate queries need to get connection from estimate pool to make sure
       // we are not blocked by data queries.
-      stmt = prepareInternal(pContext, true, true, "validate-");
-      if (stmt != null) {
-        try {
-          stmt.close();
-        } catch (SQLException e) {
-          throw new LensException();
-        }
-      }
+      prepareInternal(pContext, true, true, "validate-");
     }
   }
 
@@ -707,12 +700,12 @@ protected final ConnectionProvider getConnectionProvider() {
    * @return prepared statement of the query
    * @throws LensException
    */
-  private PreparedStatement prepareInternal(AbstractQueryContext pContext) throws LensException {
+  private void prepareInternal(AbstractQueryContext pContext) throws LensException {
     if (pContext.getDriverQuery(this) == null) {
       throw new NullPointerException("Null driver query for " + pContext.getUserQuery());
     }
     checkConfigured();
-    return prepareInternal(pContext, false, false, "prepare-");
+    prepareInternal(pContext, false, false, "prepare-");
   }
 
 
@@ -725,7 +718,7 @@ private PreparedStatement prepareInternal(AbstractQueryContext pContext) throws
    * @return prepared statement
    * @throws LensException
    */
-  private PreparedStatement prepareInternal(AbstractQueryContext pContext,
+  private void prepareInternal(AbstractQueryContext pContext,
     boolean calledForEstimate,
     boolean checkConfigured,
     String metricCallStack) throws LensException {
@@ -742,33 +735,8 @@ private PreparedStatement prepareInternal(AbstractQueryContext pContext,
     MethodMetricsContext sqlRewriteGauge = MethodMetricsFactory.createMethodGauge(pContext.getDriverConf(this), true,
       metricCallStack + COLUMNAR_SQL_REWRITE_GAUGE);
     String rewrittenQuery = rewriteQuery(pContext);
+    pContext.setSelectedDriverQuery(rewrittenQuery);
     sqlRewriteGauge.markSuccess();
-    MethodMetricsContext jdbcPrepareGauge = MethodMetricsFactory.createMethodGauge(pContext.getDriverConf(this), true,
-      metricCallStack + JDBC_PREPARE_GAUGE);
-
-    PreparedStatement stmt = null;
-    Connection conn = null;
-    try {
-      conn = calledForEstimate ? getEstimateConnection() : getConnection();
-      stmt = conn.prepareStatement(rewrittenQuery);
-      if (!pContext.getDriverConf(this).getBoolean(JDBC_VALIDATE_SKIP_WARNINGS,
-        DEFAULT_JDBC_VALIDATE_SKIP_WARNINGS) && stmt.getWarnings() != null) {
-        throw new LensException(stmt.getWarnings());
-      }
-    } catch (SQLException sql) {
-      handleJDBCSQLException(sql);
-    } finally {
-      if (conn != null) {
-        try {
-          conn.close();
-        } catch (SQLException e) {
-          log.error("Error closing connection: {}", rewrittenQuery, e);
-        }
-      }
-      jdbcPrepareGauge.markSuccess();
-    }
-    log.info("Prepared: {}", rewrittenQuery);
-    return stmt;
   }
 
   /**
@@ -807,10 +775,7 @@ public void prepare(PreparedQueryContext pContext) throws LensException {
       // already prepared
       return;
     }
-    PreparedStatement stmt = prepareInternal(pContext);
-    if (stmt != null) {
-      preparedQueries.put(pContext.getPrepareHandle(), stmt);
-    }
+    prepareInternal(pContext);
   }
 
   /**

lens-driver-jdbc/src/test/java/org/apache/lens/driver/jdbc/TestJdbcDriver.java

@@ -44,7 +44,6 @@
 import org.apache.lens.server.api.query.QueryContext;
 import org.apache.lens.server.api.query.cost.QueryCost;
 import org.apache.lens.server.api.query.cost.StaticQueryCost;
-import org.apache.lens.server.api.util.LensUtil;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hive.conf.HiveConf;
@@ -294,23 +293,7 @@ public void testEstimate() throws Exception {
   }
 
   /**
-   * Test estimate failing
-   *
-   * @throws Exception the exception
-   */
-  @Test
-  public void testEstimateFailing() throws Exception {
-    String query2 = "SELECT * FROM estimate_test2"; // Select query against non existing table
-    try {
-      driver.estimate(createExplainContext(query2, baseConf));
-      Assert.fail("Running estimate on a non existing table.");
-    } catch (LensException ex) {
-      Assert.assertEquals(LensUtil.getCauseMessage(ex), "user lacks privilege or object not found: ESTIMATE_TEST2");
-    }
-  }
-
-  /**
-   * Test estimate failing
+   * Test estimate guages
    *
    * @throws Exception the exception
    */
@@ -326,7 +309,6 @@ public void testEstimateGauges() throws Exception {
     String driverQualifiledName = driver.getFullyQualifiedName();
     Assert.assertTrue(reg.getGauges().keySet().containsAll(Arrays.asList(
       "lens.MethodMetricGauge.TestJdbcDriver-"+driverQualifiledName+"-validate-columnar-sql-rewrite",
-      "lens.MethodMetricGauge.TestJdbcDriver-"+driverQualifiledName+"-validate-jdbc-prepare-statement",
       "lens.MethodMetricGauge.TestJdbcDriver-"+driverQualifiledName+"-validate-thru-prepare",
       "lens.MethodMetricGauge.TestJdbcDriver-"+driverQualifiledName+"-jdbc-check-allowed-query")));
   }
@@ -359,7 +341,11 @@ public void testMetricsEnabled() throws Exception {
     cost = driver.estimate(pContext2);
     Assert.assertEquals(cost, JDBC_COST);
     driver.prepare(pContext2);
-    driver.explainAndPrepare(pContext2);
+
+    PreparedQueryContext pContext3 = new PreparedQueryContext(query1, "SA", metricConf, drivers);
+    cost = driver.estimate(pContext3);
+    Assert.assertEquals(cost, JDBC_COST);
+    driver.explainAndPrepare(pContext3);
   }
 
   /**
@@ -653,23 +639,6 @@ public void testPrepare() throws Exception {
     driver.prepare(pContext);
   }
 
-  /**
-   * Test prepare failing
-   *
-   * @throws Exception the exception
-   */
-  @Test
-  public void testPrepareFailing() throws Exception {
-    String query = "SELECT * FROM prepare_test2"; // Select query against non existing table
-    try {
-      PreparedQueryContext pContext = new PreparedQueryContext(query, "SA", baseConf, drivers);
-      driver.prepare(pContext);
-      Assert.fail("Running prepare on a non existing table.");
-    } catch (LensException ex) {
-      Assert.assertEquals(LensUtil.getCauseMessage(ex), "user lacks privilege or object not found: PREPARE_TEST2");
-    }
-  }
-
   /**
    * Test prepare skip warnings
    *

lens-server-api/src/main/java/org/apache/lens/server/api/query/PreparedQueryContext.java

@@ -77,7 +77,7 @@ public class PreparedQueryContext extends AbstractQueryContext implements Delaye
   /**
    * The millis in week.
    */
-  private static long millisInWeek = 7 * 24 * 60 * 60 * 1000;
+  private static long millisInTenMinutes = 10 * 60 * 1000;
 
   /**
    * Instantiates a new prepared query context.
@@ -129,7 +129,7 @@ public long getDelay(TimeUnit units) {
     if (this.prepareStartTime != null) {
       Date now = new Date();
       long elapsedMills = now.getTime() - this.prepareStartTime.getTime();
-      delayMillis = millisInWeek - elapsedMills;
+      delayMillis = millisInTenMinutes - elapsedMills;
       return units.convert(delayMillis, TimeUnit.MILLISECONDS);
     } else {
       return Integer.MAX_VALUE;

lens-server/src/main/java/org/apache/lens/server/query/LensServerDAO.java

@@ -120,7 +120,7 @@ public void createPreparedQueriesTable() throws Exception {
       log.warn("Unable to create prepared_queries queries table", e);
     }
   }
-  
+
   public void createFailedAttemptsTable() throws Exception {
     String sql = "CREATE TABLE if not exists failed_attempts (handle varchar(255) not null,"
       + "attempt_number int, drivername varchar(10000), progress float, progressmessage varchar(10000), "
@@ -845,8 +845,9 @@ public boolean deleteActiveSession(LensSessionHandle sessionId) throws LensExcep
    * @throws SQLException the exception
    */
   public void insertPreparedQuery(PreparedQueryContext preparedQueryContext) throws LensException {
-    String sql = "insert into prepared_queries (handle, userquery, submitter, timetaken, queryname, drivername, "
-        + "driverquery, starttime)" + " values (?,?,?,?,?,?,?,?)";
+    String sql =
+        "insert into prepared_queries (handle, userquery, submitter, timetaken, queryname, drivername, "
+            + "driverquery, starttime)" + " values (?,?,?,?,?,?,?,?)";
     Connection conn = null;
     try {
       conn = getConnection();
@@ -864,7 +865,7 @@ public void insertPreparedQuery(PreparedQueryContext preparedQueryContext) throw
     } catch (SQLException e) {
       log.error("Failed to insert prepared query into database with error, " + e);
       throw new LensException(e);
-  } finally {
+    } finally {
       DbUtils.closeQuietly(conn);
     }
   }

lens-server/src/main/java/org/apache/lens/server/query/QueryExecutionServiceImpl.java

@@ -2057,6 +2057,7 @@ public QueryPrepareHandle prepare(LensSessionHandle sessionHandle, String query,
       acquire(sessionHandle);
       prepared = prepareQuery(sessionHandle, query, lensConf, SubmitOp.PREPARE);
       prepared.setQueryName(queryName);
+      prepared.getSelectedDriver().prepare(prepared);
       lensServerDao.insertPreparedQuery(prepared);
       return prepared.getPrepareHandle();
     } catch (LensException e) {