Обсуждение: pgsql-sql-owner
Hi,
I am using below code in multi threaded environment, but when multiple threads are accessing then i get : "org.postgresql.util.PSQLException: ERROR: tuple concurrently updated" exception. But my concern is I need to use it in multi threaded env, for the same reason I am using FOR UPDATE with cursor. Then where is the issue??? Am I missing something????? Please help me with the same.....
Statement stmt = c.createStatement();// Setup function to call.
stmt.execute("CREATE OR REPLACE FUNCTION refcursorfunc() RETURNS refcursor AS '"
+ " DECLARE "
+ " call_log_rec call_log % rowtype; "
+ " call_log_cursor refcursor; "
+ " final_cursor refcursor; "
+ " idInt int[]; "
+ " BEGIN "
+ " OPEN call_log_cursor FOR SELECT * FROM call_log WHERE aht_read_status = 0 ORDER BY record_sequence_number ASC limit 20 FOR UPDATE; "
+ " LOOP "
+ " FETCH NEXT FROM call_log_cursor INTO call_log_rec; "
+ " EXIT WHEN call_log_rec IS NULL; "
+ " UPDATE call_log SET aht_read_status = 1 WHERE CURRENT OF call_log_cursor; "
+ " idInt := idInt || ARRAY [call_log_rec.record_sequence_number]; "
+ " END LOOP;"
+ " OPEN final_cursor FOR SELECT record_sequence_number FROM call_log WHERE record_sequence_number = ANY(idInt); "
+ " RETURN final_cursor; "
+ " END;' language plpgsql");
stmt.close();
// We must be inside a transaction for cursors to work.
c.setAutoCommit(false);
// Procedure call.
CallableStatement proc = c.prepareCall("{ ? = call refcursorfunc() }");
proc.registerOutParameter(1, Types.OTHER);
System.out.println("BEFORE::: Thread name::: " + Thread.currentThread().getName());
proc.execute();
ResultSet results = (ResultSet) proc.getObject(1);
while (results.next()) {
// do something with the results...
System.out.println("Hurrey got the results from SP........");
System.out.println("AFTER::::Thread name::: " + Thread.currentThread().getName()+ " record_sequence_number:::: "+results.getString(1));
}
c.commit();
results.close();
proc.close();
Thanks in advance Alma