Solved

Locked table with JDBC Statement.executeQuery()

Posted on 2006-07-11
5
987 Views
Last Modified: 2012-06-27
To anyone that can help, I have a problem with a Java application I am developing that interfaces to an MS SQL DB. I am running JDK 1.5 on Win2K Server using the ODBC bridge driver in JDBC. I confirmed that I have a locked table through the SQL Enterprise Manager logs. The strange thing is that it doesn't lock up until I have processed 3000 or so records. Since I am incorporating re-use code into my application, I did not look closely until now, and discover that I have code that has nested ResultSet objects trying to access the same tables like the example below:

-----------------------------------------------------------------
Connection con1 = null;
Connection con2 = null;
Statement stmt1 = null;
Statement stmt2 = null;
.
.

public void Method1InClass()
{
   String sqlQuery = null;
   String aResultString = null;
   ResultSet results1 = null;

   sqlQuery = "SELECT value1A.tableA, value1B.tableB
                     FROM tableA, tableB
                     WHERE tableA.id = tableB.id";

   con1 = DriverManager.getConnection(url,"","");
   stmt1 = con1.createStatement();

   stmt1.executeQuery(sqlQuery);

   while(results1.next())
   {
      // SOME OTHER CODE

      aResultString = results1.getString(value1A);
      Method2InClass(aResultString);

      // SOME OTHER CODE
   }

   con1.close();
   con1 = null;
   System.gc();
}

private void Method2InClass(String aName)
{
   String sqlQuery = null;
   String aResultString = null;
   ResultSet results2 = null;

   sqlQuery = "SELECT value2A.tableA, value2B.tableB
                     FROM tableA, tableB
                     WHERE tableA.value1A = aName
                     AND tableB.value2B = '<STRING>'";

   con2 = DriverManager.getConnection(url,"","");
   stmt2 = con2.createStatement();


   stmt2.executeQuery(sqlQuery); <--- CODE HANGS HERE
                                                        AFTER 3000 ROWS

   while(results2.next())
   {
      // SOME CODE TO PROCESS RESULTS
   }

   con2.close();
   con2 = null;
   stmt2 = null;
}
-------------------------------------------------------
Maybe there is something I am missing, but I would have expected the code to hang/lockup alot quicker than 3000 records, on account of the multiple ResultSet objects squashing each other from the get go. Stranger still, I do not have this problem on another DB that I access. The difference between that DB and the one I am using now, is that the DB that processes tens of thousands of records with no problem, has pointers to data in the DB, on the local disk. The DB that I am using which fails at ~3000 records, has referential data on a remote server through Samba. Any guesses as to what I can do to get past this problem (aside from re-coding things....which I'll probably end up doing anyway) or what I am doing wrong ??
Thanks.
0
Comment
Question by:jazzki
  • 2
5 Comments
 

Author Comment

by:jazzki
ID: 17082083
P.S. I also unsuccessfully tried processing the ResultSet objects in batches by trying to use Statement.setFetchSize(), but I get a "java.sql.SQLException: Invalid Fetch Size" error whenever I run my app. Don't understand.
0
 
LVL 30

Expert Comment

by:Mayank S
ID: 17089748
>> MS SQL DB. I am running JDK 1.5 on Win2K Server using the ODBC bridge driver in JDBC

Try the M$ JDBC driver instead.
0
 
LVL 30

Accepted Solution

by:
Mayank S earned 250 total points
ID: 17089757
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
ejb stateless example 2 18
How do I remove an object from a 3 40
Java: The Public Class Main 4 30
JAVA API design with micro service cloud in mind 1 43
Are you developing a Java application and want to create Excel Spreadsheets? You have come to the right place, this article will describe how you can create Excel Spreadsheets from a Java Application. For the purposes of this article, I will be u…
Introduction This article is the last of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers our test design approach and then goes through a simple test case example, how …
Viewers learn about the “for” loop and how it works in Java. By comparing it to the while loop learned before, viewers can make the transition easily. You will learn about the formatting of the for loop as we write a program that prints even numbers…
Viewers will learn one way to get user input in Java. Introduce the Scanner object: Declare the variable that stores the user input: An example prompting the user for input: Methods you need to invoke in order to properly get  user input:

808 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question