Merge pull request #3157 from taosdata/hotfix/jdbcmemleak

fix jdbc memory leaks. #3098

src/client/src/TSDBJNIConnector.c

@@ -335,6 +335,24 @@ JNIEXPORT jlong JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_getResultSetImp(
   return tres;
 }
 
+JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_isUpdateQueryImp(JNIEnv *env, jobject jobj, jlong con,
+                                                                                jlong tres) {
+  TAOS *tscon = (TAOS *)con;
+  if (tscon == NULL) {
+    jniError("jobj:%p, connection is closed", jobj);
+    return JNI_CONNECTION_NULL;
+  }
+
+  if ((void *)tres == NULL) {
+    jniError("jobj:%p, conn:%p, resultset is null", jobj, tscon);
+    return JNI_RESULT_SET_NULL;
+  }
+
+  SSqlObj *pSql = (TAOS_RES *)tres;
+
+  return (tscIsUpdateQuery(pSql)? 1:0);
+}
+
 JNIEXPORT jint JNICALL Java_com_taosdata_jdbc_TSDBJNIConnector_freeResultSetImp(JNIEnv *env, jobject jobj, jlong con,
                                                                                 jlong res) {
   TAOS *tscon = (TAOS *)con;

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java

@@ -172,6 +172,12 @@ public class TSDBJNIConnector {
 
     private native long getResultSetImp(long connection, long pSql);
     
+    public boolean isUpdateQuery(long pSql) {
+    	return isUpdateQueryImp(this.taos, pSql) == 1? true:false;
+    }
+    
+    private native long isUpdateQueryImp(long connection, long pSql);
+
     /**
      * Free resultset operation from C to release resultset pointer by JNI
      */

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBStatement.java

@@ -33,6 +33,7 @@ public class TSDBStatement implements Statement {
      * Status of current statement
      */
 	private boolean isClosed = true;
+	private int affectedRows = 0;
 
 	TSDBStatement(TSDBJNIConnector connecter) {
 		this.connecter = connecter;
@@ -60,13 +61,21 @@ public class TSDBStatement implements Statement {
 		if (resultSetPointer == TSDBConstants.JNI_CONNECTION_NULL) {
 			this.connecter.freeResultSet(pSql);
 			throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
-		} else if (resultSetPointer == TSDBConstants.JNI_NULL_POINTER) {
+		}
-//			create/insert/update/del/alter
+
+        // create/insert/update/delete/alter
+		if (resultSetPointer == TSDBConstants.JNI_NULL_POINTER) {
 			this.connecter.freeResultSet(pSql);
 			return null;
-		} else {
-			return new TSDBResultSet(this.connecter, resultSetPointer);
 		}
+		
+		if (!this.connecter.isUpdateQuery(pSql)) {
+			return new TSDBResultSet(this.connecter, resultSetPointer);
+		} else {
+			this.connecter.freeResultSet(pSql);
+			return null;
+		}
+		
 	}
 
 	public int executeUpdate(String sql) throws SQLException {
@@ -83,9 +92,10 @@ public class TSDBStatement implements Statement {
 			throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
 		}
 
-		int num = this.connecter.getAffectedRows(pSql);
+		this.affectedRows = this.connecter.getAffectedRows(pSql);
 		this.connecter.freeResultSet(pSql);
-		return num;
+		
+		return this.affectedRows;
 	}
 
 	public String getErrorMsg(long pSql) {
@@ -182,7 +192,8 @@ public class TSDBStatement implements Statement {
         if (isClosed) {
             throw new SQLException("Invalid method call on a closed statement.");
         }
-		return this.connecter.getAffectedRows(this.pSql);
+        
+		return this.affectedRows;
 	}
 
 	public boolean getMoreResults() throws SQLException {