Is there any way to invalidate metadata on Impala through jdbc?
I've tried the following (I am using Cloudera_ImpalaJDBC4_2.5.5.1007 driver):
// invalidate metadata and rebuild index on Impala
try {
Statement stmt = impalaConn.createStatement();
try {
String query = "INVALIDATE METADATA;";
ResultSet resultSet = stmt.executeQuery(query);
while (resultSet.next()) {
// do something
}
}
finally {
stmt.close();
}
}
catch(SQLException ex) {
while (ex != null)
{
ex.printStackTrace();
ex = ex.getNextException();
}
System.exit(1);
}
but I got the following exception:
java.sql.SQLDataException: [Simba][JDBC](11300) A ResultSet was expected but not generated from query "INVALIDATE METADATA;". Query not executed.
at com.cloudera.impala.exceptions.ExceptionConverter.toSQLException(ExceptionConverter.java:136)
at com.cloudera.impala.jdbc.common.SStatement.checkCondition(SStatement.java:2274)
at com.cloudera.impala.jdbc.common.SStatement.executeNoParams(SStatement.java:2704)
at com.cloudera.impala.jdbc.common.SStatement.executeQuery(SStatement.java:880)
at ico.az.deploy.TestSuite.testTeradata(TestSuite.java:103)
at ico.az.deploy.TestSuite.run(TestSuite.java:310)
at ico.az.deploy.TestSuite.main(TestSuite.java:345)
Any idea?
Yes. That query doesn't return a ResultSet. Use Statement.executeUpdate(String) instead. As the JavaDoc notes, bold added for emphasis, Executes the given SQL statement, which may be an INSERT, UPDATE, or DELETE statement or an SQL statement that returns nothing.
stmt.executeUpdate(query);
in my small test program I have some SQL Queries. The first SELECT * FROM kilometer; works properly and returns all the columns in the table. So in Java embedded, ResultSet rs = stmt.executeQuery("SELECT * FROM kilometer;"); returns an ResultSet which is not empty.
Now I wanted to get only the rows within a specific date. But my embedded query ResultSet rs = stmt.executeQuery("SELECT * FROM kilometer WHERE datum BETWEEN '2016-01-01' AND '2016-12-31';"); returns an empty ResultSet. But I've tested it online and it worked properly. Where is my mistake? I've consulted already some pages like this, but I can't find the mistake.
I am using SQLite 3.15.1 and Java SE 8.
Full java code:
public ArrayList<Strecke> getErgebnisse(final String startzeitpunkt, final String zielzeitpunkt) {
ArrayList<Strecke> strecken = new ArrayList<>();
try {
try {
if (connection != null) {
}
connection = DriverManager.getConnection("jdbc:sqlite:" + DB_PATH);
if (!connection.isClosed())
} catch (SQLException e) {
throw new RuntimeException(e);
}
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM kilometer WHERE datum BETWEEN '2016-01-01' AND '2016-12-31';");
while (rs.next()) {
strecken.add(new Strecke(Instant.ofEpochMilli(rs.getDate("datum").getTime()).atZone(ZoneId.systemDefault()).toLocalDate(), rs.getString("startort"), rs.getString("zielort"), rs.getDouble("kilometer")));
}
rs.close();
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
return strecken;
}
First of all I would recommend that you use prepared statements while executing your queries instead of passing the query directly as a string......secondly I believe the problem here is that you are passing the date as a string in quotes and not a date.....I think that is the issue here. You would need to use sqllites datetime functions for this....
I'm trying to run a query from java to PosgresSQL and I get an error from the stmt.execute(sql)
I would like to execute a new query to help me print out the specific row failing, but when I get to the catch (Exception e) the transaction is aborted.
I cant create a new transaction because I'm working with temp tables. How do I prevent the transaction to abort?
org.postgresql.util.PSQLException: ERROR: current transaction is aborted, commands ignored until end of transaction block
try (Statement stmt = data.db.getConnection().createStatement()) {
// data.db.getConnection().setSavepoint("sp01");
// insert to fact table
TableSchema factTableSchema = factInfo.getTableSchema();
// build SQL
String sql = "Select * From....";
try {
stmt.execute(sql); // this row is failing
}
catch (Exception e) {
try {
// now i would like to run a query only in case arrived here, but the transaction is closed
// how could i prevent from trasanction to close ?
ResultSet rs = stmt.executeQuery(" SELECT Bla,Bla From..");
Log.debug("");
}
catch (Exception e2) {
Log.debug("");
}
}
Create a new statement in the 2nd try block before you execute the query.
Statement stmt = data.db.getConnection().createStatement();
ResultSet rs = stmt.executeQuery(" SELECT Bla,Bla From..");
ResultSet needs to be connected and alive to perform a next();
I am trying to create a simple web app that saves user data from a form to a database and reads the content of the database back to browser upon request. Following are the functions I have written so far.
connectToDB() // connects to database
addEmployee() // adds employee to database
displayEmployee() // returns a resultSet
isExisted(int staffID) // checks if the staff already exists
Database connection function:
public void connectToDB(){
try{
// load Apache derby driver
Class.forName("org.apache.derby.jdbc.EmbeddedDriver");
} catch(ClassNotFoundException e) {
System.err.println(e);
}
try{
connection = DriverManager.getConnection(DBNAME, USERNAME, PASSWORD);
} catch(SQLException e){
System.err.println(e);
}
} // end connectToDB
Display Employee function:
public ResultSet displayEmployee(){
connectToDB();
ResultSet result = null;
try{
Statement stmt = connection.createStatement();
String query = "SELECT * FROM APP.ADDRESSBOOK";
result = stmt.executeQuery(query);
} catch(SQLException e) {
System.err.println(e);
}
return result;
}
Check if employee exists:
public boolean isExisted(int StaffID){
connectToDB();
try{
Statement stmt = connection.createStatement();
String query = "SELECT StaffNum FROM APP.ADDRESSBOOK WHERE StaffNum = " + staff_number;
ResultSet result = stmt.executeQuery(query);
while(result.next()){
int temp = result.getInt(1);
if(temp == staff_number){return true;}
}
} catch(SQLException e) {
System.err.println(e);
}
return false;
}
As you can see, if you compare the displayEmployee() and isExisted(), I am repeating mysel. Both the function works but I am looking to refactor the code. In those function I havent closed the connection. If there were 20 functions in the web app that connects to the database my code would stink.
I am looking something like this:
* THIS CODE DOESNT WORK ******
private Statement queryDB(query){
connectToDB();
Statement stmt;
try{
stmt = connection.createStatement();
} catch(SQLException e) {
System.err.println(e);
}
return stmt;
// code for closing connection
}
public ResultSet DisplayEmployee(){
String query = "SELECT * FROM APP.ADDRESSBOOK";
Statement stmt = queryDB(query);
ResultSet result = stmt.executeQuery(query);
return result;
}
Thanks.
Using raw JDBC produces a lot of unsightly boilerplate code. One solution is to use Spring JDBC Template.
In addition you will get the sql exception hierarchy which will manage the underlying JDBC exceptions automatically as runtime exceptions.
For more see:
Introduction to Spring Framework JDBC
A couple of comments:
The catch statement of ClassNotFoundException should throw an exception and shouldn't continue further.
It is not a good idea to return resultsets from a method that obtained them upon statement execution, since it is the responsibility of that method to close it. Instead, you should either read out the results into objects or cache them into CachedRowSet if your downstream functions expect a resultset.
The connectToDB method should return a successful connection or throw exception.
You could write a method that takes in an SQL query and return the results as objects so that this method can be used for retrieving based on different criteria as long you are retrieving the objects of same type.
isExisted is using staff_number which I think you intend it to be staffID. If you found a row with this value, then there is no need to check if the result set contained the row with this value, right?
My two cents!
As soon as my code gets to my while(rs.next()) loop it produces the ResultSet is closed exception. What causes this exception and how can I correct for it?
EDIT: I notice in my code that I am nesting while(rs.next()) loop with another (rs2.next()), both result sets coming from the same DB, is this an issue?
Sounds like you executed another statement in the same connection before traversing the result set from the first statement. If you're nesting the processing of two result sets from the same database, you're doing something wrong. The combination of those sets should be done on the database side.
This could be caused by a number of reasons, including the driver you are using.
a) Some drivers do not allow nested statements. Depending if your driver supports JDBC 3.0 you should check the third parameter when creating the Statement object. For instance, I had the same problem with the JayBird driver to Firebird, but the code worked fine with the postgres driver. Then I added the third parameter to the createStatement method call and set it to ResultSet.HOLD_CURSORS_OVER_COMMIT, and the code started working fine for Firebird too.
static void testNestedRS() throws SQLException {
Connection con =null;
try {
// GET A CONNECTION
con = ConexionDesdeArchivo.obtenerConexion("examen-dest");
String sql1 = "select * from reportes_clasificacion";
Statement st1 = con.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY,
ResultSet.HOLD_CURSORS_OVER_COMMIT);
ResultSet rs1 = null;
try {
// EXECUTE THE FIRST QRY
rs1 = st1.executeQuery(sql1);
while (rs1.next()) {
// THIS LINE WILL BE PRINTED JUST ONCE ON
// SOME DRIVERS UNLESS YOU CREATE THE STATEMENT
// WITH 3 PARAMETERS USING
// ResultSet.HOLD_CURSORS_OVER_COMMIT
System.out.println("ST1 Row #: " + rs1.getRow());
String sql2 = "select * from reportes";
Statement st2 = con.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
// EXECUTE THE SECOND QRY. THIS CLOSES THE FIRST
// ResultSet ON SOME DRIVERS WITHOUT USING
// ResultSet.HOLD_CURSORS_OVER_COMMIT
st2.executeQuery(sql2);
st2.close();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
rs1.close();
st1.close();
}
} catch (SQLException e) {
} finally {
con.close();
}
}
b) There could be a bug in your code. Remember that you cannot reuse the Statement object, once you re-execute a query on the same statement object, all the opened resultsets associated with the statement are closed. Make sure you are not closing the statement.
Also, you can only have one result set open from each statement. So if you are iterating through two result sets at the same time, make sure they are executed on different statements. Opening a second result set on one statement will implicitly close the first.
http://java.sun.com/javase/6/docs/api/java/sql/Statement.html
The exception states that your result is closed. You should examine your code and look for all location where you issue a ResultSet.close() call. Also look for Statement.close() and Connection.close(). For sure, one of them gets called before rs.next() is called.
You may have closed either the Connection or Statement that made the ResultSet, which would lead to the ResultSet being closed as well.
Proper jdbc call should look something like:
try {
Connection conn;
Statement stmt;
ResultSet rs;
try {
conn = DriverManager.getConnection(myUrl,"","");
stmt = conn.createStatement();
rs = stmt.executeQuery(myQuery);
while ( rs.next() ) {
// process results
}
} catch (SqlException e) {
System.err.println("Got an exception! ");
System.err.println(e.getMessage());
} finally {
// you should release your resources here
if (rs != null) {
rs.close();
}
if (stmt != null) {
stmt.close();
}
if (conn != null) {
conn.close();
}
}
} catch (SqlException e) {
System.err.println("Got an exception! ");
System.err.println(e.getMessage());
}
you can close connection (or statement) only after you get result from result set. Safest way is to do it in finally block. However close() could also throe SqlException, hence the other try-catch block.
I got same error everything was correct only i was using same statement interface object to execute and update the database.
After separating i.e. using different objects of statement interface for updating and executing query i resolved this error. i.e. do get rid from this do not use same statement object for both updating and executing the query.
Check whether you have declared the method where this code is executing as static. If it is static there may be some other thread resetting the ResultSet.
make sure you have closed all your statments and resultsets before running rs.next. Finaly guarantees this
public boolean flowExists( Integer idStatusPrevious, Integer idStatus, Connection connection ) {
LogUtil.logRequestMethod();
PreparedStatement ps = null;
ResultSet rs = null;
try {
ps = connection.prepareStatement( Constants.SCRIPT_SELECT_FIND_FLOW_STATUS_BY_STATUS );
ps.setInt( 1, idStatusPrevious );
ps.setInt( 2, idStatus );
rs = ps.executeQuery();
Long count = 0L;
if ( rs != null ) {
while ( rs.next() ) {
count = rs.getLong( 1 );
break;
}
}
LogUtil.logSuccessMethod();
return count > 0L;
} catch ( Exception e ) {
String errorMsg = String
.format( Constants.ERROR_FINALIZED_METHOD, ( e.getMessage() != null ? e.getMessage() : "" ) );
LogUtil.logError( errorMsg, e );
throw new FatalException( errorMsg );
} finally {
rs.close();
ps.close();
}
A ResultSetClosedException could be thrown for two reasons.
1.) You have opened another connection to the database without closing all other connections.
2.) Your ResultSet may be returning no values. So when you try to access data from the ResultSet java will throw a ResultSetClosedException.
It happens also when using a ResultSet without being in a #Transactional method.
ScrollableResults results = getScrollableResults("select e from MyEntity e");
while (results.next()) {
...
}
results.close();
if MyEntity has eager relationships with other entities. the second time results.next() is invoked the ResultSet is closed exception is raised.
so if you use ScrollableResults on entities with eager relationships make sure your method is run transactionally.
"result set is closed" happened to me when using tag <collection> in MyBatis nested (one-to-many) xml <select> statement
A Spring solution could be to have a (Java) Spring #Service layer, where class/methods calling MyBatis select-collection statements are annotated with
#Transactional(propagation = Propagation.REQUIRED)
annotations being:
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
this solution does not require to set the following datasource properties (i.e., in JBoss EAP standalone*.xml):
<xa-datasource-property name="downgradeHoldCursorsUnderXa">**true**\</xa-datasource-property>
<xa-datasource-property name="resultSetHoldability">**1**</xa-datasource-property>