JDBC & Open Cursors

Hi,
Could it be possible that even if all ResultSet and Statement objects are closed (in finally blocks so that the close() statements are guaranteed to be executed), one can still get ORA 1000 or max open cursors exceeded? Is there a bug in JDBC that makes the cursors linger even though they have been closed by the program? I ask this because a colleague of mine insists that there is such a JDBC bug and that the only workaround is to close the Connection object. He also claims that the "bug" is fixed in Oracle 9i. We are using Oracle 8.1.7.0.0 on HP-UX 11.0 with java 1.3.1 Any info greatly appreciated. Thanks.
Vasu

Max cursors open, is the problem encountered because of the database limitation of opening of new sessions. A new database session is created whenever a Statement/PreparedStatament is opened.
Make sure to close, Statement/PreparedStatement after its usage, as you have done in finally. This will ensure that it wont exceed the maximum open cursor limit.
I think this is the only cause for the baove problem and can be avoided.
Hope this helps
Ravi

Similar Messages

JDBC Error: ORA-01000: maximum open cursors exceeded

Post Author: prashant
CA Forum: Information OnDemand
I successfully created reports using CR4E on windows, deployed JSPS to Websphere running on windows and was able to view a large reports for a using JNDI connection resources to Oracle 10g.
Every time report is called, it consume 12 cursors from of the database. Open_cursors count is 300. After 24 or 25 iteration of this report, it throws ORA-01000: maximum open cursors exceeded error.
Has anyone seen this problem, and if so where can I find a hot fix/patch. Any help would very much be appreciated.

The following code reproduces the problem for me. I thought this was just related to when an exception occurs, and close occurs immediately afterwards. Close finds the exception that occured, and throws it without releasing the resources.
It's a pain in the ass, that's for sure.
public void go() {
try{
long startTime = System.currentTimeMillis();
String sql = "Select number_7_0__, char_10__, varchar_5__, varchar2_10__, number_10_5__, float_126__, date_, clob_, blob_ FROM lotsofrows";
Properties connectProps = new Properties();
Driver drv = new oracle.jdbc.driver.OracleDriver();
connectProps.put("user", "borg");
connectProps.put("catalog", "test");
connectProps.put("password", "borgborg");
Connection conn = drv.connect("jdbc:oracle:thin:@142.176.134.166:1521:test", connectProps);
int cnt = 0;
while (true) {
try {
System.out.print("\nTest " + ++cnt + " ");
Statement stmt = conn.createStatement();
System.out.print("execute ");
ResultSet rs = stmt.executeQuery(sql);
System.out.print("cancel ");
stmt.cancel();
try {
System.out.print("close.");
stmt.close();
} catch (SQLException se) {
if (se.getMessage().indexOf("requested cancel") != -1) {
System.out.print("URC:Close");
try {
stmt.close();
} catch (Exception ee) {
System.out.println(ee.getMessage());
ee.printStackTrace();
} else {
throw se;
stmt = null;
}catch(Exception se) {
System.out.println(se.getMessage());
se.printStackTrace();
}catch(Exception e) {
System.out.println(e.getMessage());
e.printStackTrace();
null

ORA-01000: maximum open cursors exceeded (please help / JDBC guru needed)

ORA-01000: maximum open cursors exceeded
I am getting this error when trying to execute 2,500 Sql DDL statements. I am executing the statement with:
public boolean execute(String sql) ( like stmt.execute(sql); )
After each execute() I close the statement ( like stmt.close() )
I tried taking this a step further and decided to close and reopen the database connection after every 100 Sql statements processed and I still get this exception when continuing.
ORA-01000: maximum open cursors exceeded
Any help will be greatly appreciated. I need to figure how to close the cursors or how to finish processing all 2,500 statements. I do not have control over the init.ora file and can not increase the max cursors. I hope to figure out how to close the cursors so that no tweaking of the init.ora file is needed.
ChrisTD

Why dont you allocate dukes for this problem ???
am getting this error when trying to execute 2,500 Sql DDL statements. I am executing the statement with:
public boolean execute(String sql) ( like stmt.execute(sql); )
After each execute() I close the statement ( like stmt.close() )
What kind of DDL is that? are you using any cursor operations to fetch the data? What kind of query does this sql parameter contain?
Look there is only 3 solutions for this kind of problem.
1) shutdown the database and restart it.
I dont think closing connection will shutdown the database as you
told.
2) shutdown the database access init.ora and increase the
OPEN_CURSORS and then restart it.
You told that you dont have access to init.ora.
3) close every cursor that you open.(Probably you are not closing the cursor once you fetch the data).

Oracle and "Maximum open cursors exceeded"

Hi,
I am using Weblogic 7.0sp2 with Oracle 9.2.0. Since we are using manual JTA
transactions and the 9.2 drivers are buggy in that respect, we are using the
9.0.1 thin drivers delivered with weblogic.
The problem I have is that after a while, we get the now classic "Maximum open
cursors exceeded" error on connections from our connection pool (used through
a
TX datasource). I have of course checked all our JDBC code and it is fine. We
do not leave any statement/connection open. In fact, I am certain that the
problem is not caused by our applicative code.
The reason I am so positive is that the numbers of open (cached) cursors is
growing, even though there is no activity on our application (I mean no
activity at all). The number of cursors is regurlarly increasing by one
every 5 minutes until it reaches the maximum allowed for a session.
I have listed the statements corresponding to the opened cursors (they
do not belong to our code, as you might have guessed):
SELECT sysdate, user from dual
select longdbcs from javasnm$ where short = :1
select longname from javasnm$ where short = :1
As you can see, there are only three different statements. You can get
the statements from the system view v$open_cursor for a given session
but it will only give one row per different statement. If you want to know
the # of opened cursors in your cursor, use v$sesstat with statistic# = 3
(opened cursor current).
I suspect something is wrong in the connection testing done by weblogic
for the pool (I have activated test on reserved connections and test table
name is "dual") that leaves a resultset/statement behind. What is weird
though is that the refresh period is still 0 (not 5 minutes as you would
expect from the cursor growth rate...).
I would not say that it is an Oracle bug (as stated in some BEA FAQ I read)
since our application JDBC code does not exhibit the same problem. The
problem appeared with recent version of WebLogic for which the session
cursor cache is enabled, I suppose for performance reasons - this
is set by isssuing "ALTER SESSION SET SESSION_CACHED_CURSORS = ...".
Talking about this, does anybody know to which value WebLogic sets this
parameter when intializing the connection (this is neither
documented/configurable)?
Up to now, I have come up with possibly two workarounds, neither of which
is satisfying:
- resetting the pool from time to time
- issuing "ALTER SESSION SET SESSION_CACHED_CURSORS = 0" when I get a
connection from the pool. I have not tested this one personally (read
in a newsgroup that someone else did successfully) but it is supposed
to reset the cursor cache that is causing the trouble.
Any help will be greatly appreciated,
Regards,
Thierry.

Thierry Rouget wrote:
Hi,
I am using Weblogic 7.0sp2 with Oracle 9.2.0. Since we are using manual JTA
transactions and the 9.2 drivers are buggy in that respect, we are using the
9.0.1 thin drivers delivered with weblogic.
The problem I have is that after a while, we get the now classic "Maximum open
cursors exceeded" error on connections from our connection pool (used through
a
TX datasource). I have of course checked all our JDBC code and it is fine. We
do not leave any statement/connection open. In fact, I am certain that the
problem is not caused by our applicative code.
The reason I am so positive is that the numbers of open (cached) cursors is
growing, even though there is no activity on our application (I mean no
activity at all). The number of cursors is regurlarly increasing by one
every 5 minutes until it reaches the maximum allowed for a session.
I have listed the statements corresponding to the opened cursors (they
do not belong to our code, as you might have guessed):
SELECT sysdate, user from dual
select longdbcs from javasnm$ where short = :1
select longname from javasnm$ where short = :1
As you can see, there are only three different statements. You can get
the statements from the system view v$open_cursor for a given session
but it will only give one row per different statement. If you want to know
the # of opened cursors in your cursor, use v$sesstat with statistic# = 3
(opened cursor current).
I suspect something is wrong in the connection testing done by weblogic
for the pool (I have activated test on reserved connections and test table
name is "dual") that leaves a resultset/statement behind. What is weird
though is that the refresh period is still 0 (not 5 minutes as you would
expect from the cursor growth rate...).
I would not say that it is an Oracle bug (as stated in some BEA FAQ I read)
since our application JDBC code does not exhibit the same problem. The
problem appeared with recent version of WebLogic for which the session
cursor cache is enabled, I suppose for performance reasons - this
is set by isssuing "ALTER SESSION SET SESSION_CACHED_CURSORS = ...".
Talking about this, does anybody know to which value WebLogic sets this
parameter when intializing the connection (this is neither
documented/configurable)?
Up to now, I have come up with possibly two workarounds, neither of which
is satisfying:
- resetting the pool from time to time
- issuing "ALTER SESSION SET SESSION_CACHED_CURSORS = 0" when I get a
connection from the pool. I have not tested this one personally (read
in a newsgroup that someone else did successfully) but it is supposed
to reset the cursor cache that is causing the trouble.
Any help will be greatly appreciated,
Regards,
Thierry.Hi. We don't make those queries either. I suspect they are internal to the
oracle driver. One thing you can try is to set the size of the pool's
statement cache to zero. Oracle will retain cursors for every statement we
cache. The alternative is also to tell the DBMS to allow a given session
more cursors.
Joe

Open cursors exceeded - common problem, different scenario

I searched both the web and the java forums and found the "maximum open cursors exceeded" to be a very common problem, one in which I have, but I can't seem to solve it and I was wondering if the way I am doing certain things are causing it.
Here is my program. I have a java server running that is acting as a midway between a java applet and an Oracle database. Since many users will most likely be using the applet, and since the applet has the ability to alter data in the database, I wanted to Synchronize my database connections.
So because of this, my server has a static class with all the database calls, including a connection call that connects to the database when it is first started up. Also, I return ResultSets to the server, but I never close either my ResultSet or my Statement. I do this because I only have one global of each of them. Otherwise I would have to close them from the server, and this worries me as far synchronization goes. Thus, with a global statement, I am just reinstantiating it every time. This may very well be my problem.
Should I?
1. Not have a single connection to the database but instead create a new connection every time a database call is made?
2. Do not make the resultset and statement global. (And if this is yes, how would I go about closing them after I return the result set to the server).
3. Leave the resultset and statement global but go ahead and try to close them from the server.
4. Or any combination of the above.
Thanks. I appreciate any help advance. This problem has been driving me insane the last couple of days. If it would help to post my database connections code then I will gladly do so.

Hmmm. I have worked on it all day and still have nothing. If anyone has even a shred of help, that would be greatl appreciated. I am going to just go ahead and post my code just in case that helps anyone.
import java.net.*;
import java.sql.*;
import java.io.*;
import oracle.jdbc.driver.*;
class DBOracleCon
     final static String          DBHostName = "hostname",
                         DBPortNumber = "12345",
                         DBId ="myid";
     final static String          UserName = "user",
                         Password = "password";
     private static Connection con;
     private static Statement stmt;
     private static ResultSet rs;
     static protected void dbConnection ()
          try
               DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
                    String dbConnectString =
                    "(DESCRIPTION=(ADDRESS=(HOST=" + DBHostName + ")"+
                    "(PROTOCOL=tcp)(PORT="+ DBPortNumber + "))"+
                    "(CONNECT_DATA=(SID="+ DBId + ")))";
               con = DriverManager.getConnection(
                        "jdbc:oracle:thin:@"+dbConnectString,
                        UserName, Password);
                      con.setAutoCommit(false);
          catch (Exception e)
               System.out.println ("Connection Error:" + e);
     static public synchronized Connection returnConnection ()
          return con;
     static protected synchronized ResultSet executeQuery (String query)
          try
               stmt = con.createStatement();
               //System.out.println ("QUERY: " + query);
               rs = stmt.executeQuery (query);
               return rs;
          catch (Exception e)
               System.out.println (e);
               e.printStackTrace();
               return null;
     static protected synchronized ResultSet executeQuery (PreparedStatement ps)
          try
               rs = ps.executeQuery();
               return rs;
          catch (Exception e)
               System.out.println (e);
               e.printStackTrace();
               return null;
     static protected synchronized void executeUpdate (String query)
          try
               stmt = con.createStatement();
               System.out.println ("UPDATE: " + query);
               stmt.execute (query);
               commit();
          catch (Exception e)
               System.out.println (e);
               e.printStackTrace();
     static protected void executeUpdate (PreparedStatement ps)
          try
               ps.executeUpdate();
               commit();
          catch (Exception e)
               System.out.println (e);
               e.printStackTrace();
     static private void commit ()
          try
               stmt = con.createStatement();
               stmt.execute ("commit");
          catch (Exception e)
               System.out.println (e);
}Thanks.

More on "maximum open cursors exceeded"

It seems a lot of people have been seeing this error message, but reading through the posts on the topic hasn't given me any new insight on the problem. Here's an account of my particular situation:
I am using the XSQL servlet, v.1.0.0.0 with the thin jdbc driver v.1.x. The servlet is running within an Apache server (1.3.12) on a Linux box, and the Oracle database (8.1.5) is located on a Solaris 2.6 machine.
The servlet accepts HTTP connections, performs the corresponding SQL queries and returns the output from the database to the HTTP client. Here's a simple example:
(Sorry about potential bad line breaks.)
client request:
% telnet xsql-host.some.domain 80
Trying xxx.xxx.xxx.xxx
Connected to xsql-host.some.domain.
GET /xsql/test/listall.xsql
<server response here>
listall.xsql:
<?xml version="1.0"?>
<page connection="boss" xmlns:xsql="urn:oracle-xsql">
<accounts>
<xsql:query tag-case="lower" rowset-element="" row-element="accountinfo">
select * from test
</xsql:query>
</accounts>
</page>
Very simple stuff indeed. Now, this has worked perfectly for 3 weeks or so. During this period, the xsql servlet has been stopped and restarted numerous times and the machine hosting the database has been rebooted at least three times. Then, for no apparent reason (as nothing had changed in the setup described above), I started getting "maximum open cursors exceeded" on every request. Since then, I have been unable to get the system working as it had up until now. I haven't restarted the database and I would like to avoid doing so, because that would not be a valid solution for us if the problem reappeared in production. The maximum open cursors setting in Oracle should be correct, since things were running smoothly before.
From what I can see, the problem could be with the servlet not closing its cursors. One post mentioned that it did, but I would appreciate it if this could be double-checked. Considering the database is the only portion of the system which has been kept running for extended periods of time, it seems to me that this might indeed be the problem.
Confirmation, workarounds, suggestions, patches, or a consolation box of chocolates would all be appreciated.
Thanks,
- Fad
([email protected])
null

Check which process is making all the cursors on which database. If it is your procedure, try explicitly closing the cursors. I think the cursors are only implicitely closed after the transaction is ended. If you loop and open a cursor within the loop, that might be the problem.
I also had this problem with Java working over a JDBC connection some time ago on a 815 database. If I recall correctly, that was caused by the JDBC driver and fixed by replacing it with a JDBC driver of 9i.
The following script is what I used previously in a program that can draw a graph from the results. It is ugly, but does the job.
Hope this helps,
L.
select
'max cursors',
to_number(value)
from
v$parameter
where
name = 'open_cursors'
union
select
substr(lower(username),1,10)||'('||substr(to_char(ses.sid)||','
||to_char(serial#),1,9)||')',
s.value
from
v$sesstat s,
v$statname n,
v$session ses
where
s.statistic#=n.statistic#
and ses.sid=s.sid
and n.name like '%cursor%'
and n.name like '%current%'
and not (ses.sid between 1 and 6)

ORA-01000: maximum open cursors exceeded

I ran into this Too many Open Cursors Issue
My environment is
WebLogic 6.1 SP2
Oracle 8.1.7.3.0
JDBC Thin Driver
WebLogic Connection Pools
Tried all the solutions given in the news group for issues, none seemed to work,
so deviced a work around.
just wanted to know if there is a better solution that works.
or else we will go ahead with the workaround...
Explanation follows...
When we work with the weblogic connection pool
Using the WebLogic Pool Driver, we ask for a connection from Weblogic connection
pool.
WebLogic connection pool uses the Oracle Driver to connect to the Oracle Database.
creates a connection and provides it to us.
as we work with this connection, we create prepared statements, execute them etc.
etc. and this will create cursors in the oracle database.
now when we close the connection from our program, what gets closed is the connection
created between our program and the WebLogic Connection Pool
but the connection between the WebLogic Connection Pool and the Oracle database still
remains open, well, there is nothing wrong in that after all that is how connection
pool has to work.
but the issue here is the open cursors that are cached in oracle when we created
statements are not closed even after we close the statements and the connections,
since according to oracle, the connection is still active becuase WebLogic connection
pool is still maintaining the connection. and oracle will clear that only when the
connection is closed with it.
WebLogic pool driver is supposed to clear up the open cursor cache. but i guess it
is not doing it.
I did some R&D and tried out the following solutions and they dont seem to solve
the issue. (Most of them were picked up from the News groups)
1. Include the latest Oracle type 4 driver in class path before the other classes
2. Put a Connection.rollback before closing connection
3. Use the Oracle Driver directly bypassing the Connection Pool. (This works... but
we cant do that becuase we are using connection pools to handle connection.)
So I came up with the following work around.
Whenever a connection is created from oracle, internally the driver creates a session
with oracle.
when weblogic pool driver creates a session it uses an ORACLE session parameter SESSION_CACHED_CURSORS
I guess WebLogic sets it to a high number. But there has to be a parameter which
we can configure to control this when we create out connection pool. the closest
parameter was found to be "Prepared Statement Cache Size" but even after making it
0 it doesnt seem to improve the situation.
so, to override the SESSION_CACHED_CURSORS in our connection. every time we get a
connection we have to execute a query to alter the session paramater SESSION_CACHED_CURSORS
as follows
woConn = java.sql.DriverManager.getConnection(DCConstants.DC_JDBC_URL);
try
Statement woTmpStmt = woConn.createStatement();
woTmpStmt.execute("ALTER SESSION SET SESSION_CACHED_CURSORS = 0");
woTmpStmt.close();
catch(SQLException woSQLEx)
DCDebug.logInfo("DCDataFactory","Unable to alter session");
regards
Gulam

Hi. If you'e turned off our statement cache (by setting it's size to zero),
then it's a DBMS-side issue only. When you return a connection to the
pool (by closing it), we will close any statements and result sets you
had created but not closed, so we do all we can. In fact if you left
the connection in an autoCommit(false) mode, we do the rollback for you
too. Besides setting that DBMS-side option you do with SQL, the only
other option I see is to configure your DBMS/session info for Oracle,
to allow more open cursors per connection than you currently allow.
Joe Weinstein at B.E.A.
Gulam Dasthagir wrote:
I ran into this Too many Open Cursors Issue
My environment is
WebLogic 6.1 SP2
Oracle 8.1.7.3.0
JDBC Thin Driver
WebLogic Connection Pools
Tried all the solutions given in the news group for issues, none seemed to work,
so deviced a work around.
just wanted to know if there is a better solution that works.
or else we will go ahead with the workaround...
Explanation follows...
When we work with the weblogic connection pool
Using the WebLogic Pool Driver, we ask for a connection from Weblogic connection
pool.
WebLogic connection pool uses the Oracle Driver to connect to the Oracle Database.
creates a connection and provides it to us.
as we work with this connection, we create prepared statements, execute them etc.
etc. and this will create cursors in the oracle database.
now when we close the connection from our program, what gets closed is the connection
created between our program and the WebLogic Connection Pool
but the connection between the WebLogic Connection Pool and the Oracle database still
remains open, well, there is nothing wrong in that after all that is how connection
pool has to work.
but the issue here is the open cursors that are cached in oracle when we created
statements are not closed even after we close the statements and the connections,
since according to oracle, the connection is still active becuase WebLogic connection
pool is still maintaining the connection. and oracle will clear that only when the
connection is closed with it.
WebLogic pool driver is supposed to clear up the open cursor cache. but i guess it
is not doing it.
I did some R&D and tried out the following solutions and they dont seem to solve
the issue. (Most of them were picked up from the News groups)
1. Include the latest Oracle type 4 driver in class path before the other classes
2. Put a Connection.rollback before closing connection
3. Use the Oracle Driver directly bypassing the Connection Pool. (This works... but
we cant do that becuase we are using connection pools to handle connection.)
So I came up with the following work around.
Whenever a connection is created from oracle, internally the driver creates a session
with oracle.
when weblogic pool driver creates a session it uses an ORACLE session parameter SESSION_CACHED_CURSORS
I guess WebLogic sets it to a high number. But there has to be a parameter which
we can configure to control this when we create out connection pool. the closest
parameter was found to be "Prepared Statement Cache Size" but even after making it
0 it doesnt seem to improve the situation.
so, to override the SESSION_CACHED_CURSORS in our connection. every time we get a
connection we have to execute a query to alter the session paramater SESSION_CACHED_CURSORS
as follows
woConn = java.sql.DriverManager.getConnection(DCConstants.DC_JDBC_URL);
try
Statement woTmpStmt = woConn.createStatement();
woTmpStmt.execute("ALTER SESSION SET SESSION_CACHED_CURSORS = 0");
woTmpStmt.close();
catch(SQLException woSQLEx)
DCDebug.logInfo("DCDataFactory","Unable to alter session");
regards
Gulam

Viewer leaving open cursors in Oracle

We are using the JRC to display reports in our software. We are running jboss-4.2.0 as our application server. The backend could be either SQL Server or Oracle. For Oracle we are using the oracle.jdbc.driver.OracleDriver driver. The reports are set up using a JDBC (JNDI) connection. Generally we have it working ok but in Oracle the JRC is leaving open cursors leading to ORA-01000: MAXIMUM OPEN CURSORS EXCEEDED. I have found that a new cursor is opened when the data source is changed in the following code snippet
Iterator tableIT = tableNames.iterator();
while (tableIT.hasNext()) {
ITable oldTable = (ITable)tableIT.next();
ITable table = (ITable) ((IClone)oldTable).clone(true);
table.setQualifiedName(table.getName());
clientDoc.getDatabaseController().setTableLocation(oldTable, table);
When we hit the last line in this loop, a new cursor is opened in Oracle so if a report has 10 tables, I get 10 cursors opened. I know that I need to close the cursors somehow but nothing I do seems to make a difference. After my processHttpRequest call to the viewer I added:
crystalReportPageViewer.getReportSource().dispose();
clientDoc.getReportSource().dispose();
The code definately executes but the the number of open cursors in Oracle does not change. I am at a loss.

A couple more things to think about then.
1. When you go through your loop to set your table location, you are using the clone method to create a new table and then pass that table to the report. Cloning tables is no longer necessary with the JRC. We do know that a fix was provided for the JRC SDK, however this fix would probably not have been applied to the clone method since it has been deprecated.
I have attached a sample that shows the new methodology for setting table location; very similar, just not using clone anymore.
2. When you want to destroy any connections that the ReportClientDocument has made, you will need to call .close() on this object. This can be done in conjunction with the viewer.dispose(). One thing to note is that if you call the .close() method, it will need to be done as the user is closing the browser, or you will not have access to your report object when you have it open in the HTML Viewer.

Maximum open cursors exceeded when inserting to a remote db

I receive the error:
ORA-01000: maximum open cursors exceeded
ORA-02063: preceding line
from ONTARIO
(where ONTARIO is my remote db) when I am performing inserts from a pl/sql procedure to the remote db. I am performing two inserts from inside pl/sql and then issuing an explicit commit. I checked the open_cursors init param on both the local db and remote db and it was set to 300. I bumped up the remote db init param to 600. I was able to perform more inserts but still received this error.
I thought implicit cursors close themselves, especially after a commit. Do I need to do something special to close the cursors on the remote machine?
Thanks for your time...

Check which process is making all the cursors on which database. If it is your procedure, try explicitly closing the cursors. I think the cursors are only implicitely closed after the transaction is ended. If you loop and open a cursor within the loop, that might be the problem.
I also had this problem with Java working over a JDBC connection some time ago on a 815 database. If I recall correctly, that was caused by the JDBC driver and fixed by replacing it with a JDBC driver of 9i.
The following script is what I used previously in a program that can draw a graph from the results. It is ugly, but does the job.
Hope this helps,
L.
select
'max cursors',
to_number(value)
from
v$parameter
where
name = 'open_cursors'
union
select
substr(lower(username),1,10)||'('||substr(to_char(ses.sid)||','
||to_char(serial#),1,9)||')',
s.value
from
v$sesstat s,
v$statname n,
v$session ses
where
s.statistic#=n.statistic#
and ses.sid=s.sid
and n.name like '%cursor%'
and n.name like '%current%'
and not (ses.sid between 1 and 6)

Maximum Open Cursors Exceeded problem in XSQL

Hi,
We are processing an XSQL page by calling XSQLRequest.process() programatically within our application. Within the XSQL page there are several queries which involve multiple nested CURSOR expressions... when the query returns enough rows we are running into the error "ORA-00604: error occurred at recursive SQL level 1 ORA-01000: maximum open cursors exceeded".
When searching this forum I have seen many (old) postings regarding this error and a bug in the XDK... seems like it was some time ago, but while we set about improving the structure of our XSQL page (or increasing the max open cursor init parameter currently at 500 or both) can anyone confirm that this bug no longer exists?
Also, any general suggestions on working around this limit rather than increasing it? We have considered splitting up our queries into smaller queries (and merging the results via XSLT) and closing cursors during the session explicitly by issuing commits within the XSQL page... but any better ideas?
Thanks,
Bob

I have found this max open cursors problem to be related to Statement object not being closed. This presents a problem for the use of PreparedStatements, because they are only useful if you can keep them open and resuse them. However, in doing so, each iteration through the PreparedStatement creates another open cursor in the databse rather than reusing the previous one. A work around I discovered by reading about REF CURSORS and I use in JDBC is as follows:
Assuming a previously prepared PreparedStatement pstmt and a ResultSet rset-
while (rset.next()) {
rset.close();
// This line closes the cursor in the database
// but does not require you to re-prepare the
// PreparedStatement. Don't ask me why--ask the
// Oracle API guys.
rset.getStatement().close();
// make ready for GC
rset = null;

SQLException: maximum open cursors exceeded

hi all,
i get the following exception when executing my program.
14:36:02,111 ERROR [STDERR] java.sql.SQLException: ORA-01000: maximum open cursors exceeded
14:36:02,111 ERROR [STDERR]     at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:134)
14:36:02,111 ERROR [STDERR]     at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:289)
14:36:02,111 ERROR [STDERR]     at oracle.jdbc.ttc7.Oopen.receive(Oopen.java:120)
14:36:02,111 ERROR [STDERR]     at oracle.jdbc.ttc7.TTC7Protocol.open(TTC7Protocol.java:586)
14:36:02,127 ERROR [STDERR]     at oracle.jdbc.driver.OracleStatement.<init>(OracleStatement.java:385)
14:36:02,127 ERROR [STDERR]     at oracle.jdbc.driver.OracleConnection.privateCreateStatement(OracleConnection.java:772)
14:36:02,127 ERROR [STDERR]     at oracle.jdbc.driver.OracleConnection.createStatement(OracleConnection.java:712)
14:36:02,127 ERROR [STDERR]     at org.jboss.resource.adapter.jdbc.WrappedConnection.createStatement(WrappedConnection.java:145)
14:36:02,127 ERROR [STDERR]     at abcd.updateMethod(abcd.java:1605)
14:36:02,127 ERROR [STDERR]     at servlet.abcdServlet.doPost(abcdServlet.java:62)
14:36:02,127 ERROR [STDERR]     at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
14:36:02,127 ERROR [STDERR]     at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
14:36:02,143 ERROR [STDERR]     at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
14:36:02,143 ERROR [STDERR]     at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
14:36:02,143 ERROR [STDERR]     at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
14:36:02,143 ERROR [STDERR]     at org.jboss.web.tomcat.tc5.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:156)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
14:36:02,143 ERROR [STDERR]     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
14:36:02,143 ERROR [STDERR]     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
14:36:02,143 ERROR [STDERR]     at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
14:36:02,143 ERROR [STDERR]     at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
14:36:02,143 ERROR [STDERR]     at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)the code is like this
while (result.next())
                       String sql = "update query";
                       Statement = null;
               st = con.createStatement(); // line No. 1605
               st.executeUpdate(sql);
               st.close();
}anyone had such experience? please post your valuable suggestions.

You have better to select your data (select connection) and store them in an arraylist for example, then close the 'select connection' and finally
loop through the arraylist and make as much update as the list size.I disagree. Huge amounts of data could be being pulled from the database (that is one of their strength) and if the data can be processed one row at a time there is no reason to load it all into memory.
=> take a look [here |http://java.sun.com/docs/books/tutorial/jdbc/TOC.html]
and [here |http://java.sun.com/docs/books/tutorial/jdbc/basics/prepared.html] for preparedstatements
Ditto to PreparedStatement
OP. Is it possible that the Statement being returned (from what looks like JBoss) has the close method overwritten and does not actually return the resource (some type of pooling)?

Oracle - maximum open cursors exceeded

Hi! I'm constatly getting the error I pasted below, when this line is executed:
PreparedStatement stmt = connection.prepareStatement(sqlStatement);
'connection' is of course an instance of oracle.jdbc.driver.OracleConnection, and 'sqlStatement' is a normal INSERT statement.
Now, why I'm getting an error that involves cursos if the statement is an insert? One more thing, this error is happening in some enviroments so I think it could be an orcacle server problem (like installation or configuration problem), or it could be the driver, or... I dont know :)
Well, I hope anyone can give me a tipo about this... Thanks in advance.
Dario
ORA-01000: maximum open cursors exceeded
java.sql.SQLException: ORA-01000: maximum open cursors exceeded
at oracle.jdbc.dbaccess.DBError.throwSqlExceptionDBError.java:180)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:208)
at oracle.jdbc.ttc7.Oopen.receive(Oopen.java:118)
at oracle.jdbc.ttc7.TTC7Protocol.open(TTC7Protocol.java:472)
at oracle.jdbc.driver.OracleStatement.<init>OracleStatement.java:499)
at oracle.jdbc.driver.OracleStatement.<init>OracleStatement.java:518)
at oracle.jdbc.driver.OraclePreparedStatement.<init>OraclePreparedStatement.java:210)
at oracle.jdbc.driver.OraclePreparedStatement.<init>OraclePreparedStatement.java:193)
at oracle.jdbc.driver.OracleConnection.privatePrepareStatementOracleConnection.java:869)
at oracle.jdbc.driver.OracleConnection.prepareStatementOracleConnection.java:704)
------------------------------------------

Thanks a lot for all the answers...
After some tests a made, I found out that in the enviroment I developed the application, the value of the parameter OPEN_CURSORS is 300. I don't know yet which is the value in the test enviroment (where the errors are happening) but I'm pretty sure it is smaller, since I could force the same error in the development enviroment increasing the concurrency of the application (ie, I force the application too many create prepare statements, even much more than the real values the application should accept).
Well, I have to thank you all again...
Dario

Maximum open cursors exceeded prblm , code attached for review

I am getting the following exception in my code
java.sql.SQLException: ORA-01000: maximum open cursors exceeded
My code is as follows
     public ResultSet getFiles() throws Exception
          ResultSet rs = null;
          PreparedStatement pst = null;
          String fileqry = "select * from FILES_SENT where FILESTATUS= 'TOBS' ";
          pst = connection.prepareStatement(fileqry);
          try
               rs = pst.executeQuery();
          catch(Exception e)
               System.out.println("In getFiles" + e );
               System.exit(0);
          return rs;
     public void RUN()
          while(true)
               try
                    System.out.println("opening cursor " );
                    FileResultSet = getFiles(); // polling the DB for new messages
                    if (FileResultSet!= null && FileResultSet.next()) // if new files are found
                         do // for each of the records
                              String Filename = FileResultSet.getString("FILENAME");
                              System.out.println("Processing the file " + Filename);
                              // getting the messagetype from the filename
                              String MessageType= Filename.substring(0,1);
                              String InternalMessageID = getInternalMessageID(MessageType);
                              System.out.println("internalmessageid of the file " + InternalMessageID);
                         while (FileResultSet.next());
                         System.out.println("Processed all messages");
                    else
                         System.out.println("closing cursor " );
                         FileResultSet.close();
                    Thread.sleep(10);
               catch(Exception f)
                    System.out.println("exception in RUN " + f);
                    System.exit(0);
     }The database is oracle 10g
The loop is going for 300 times with out any data and then comes down with this exception.
Experts please give your valuable help in this.
Dinesh

I had previously tried to close the statement
immediately after the exceute statement , but the
resultset is lost after that .
So where shoud i close the statement ?Don't keep ResultSets around! See this whole thread:
http://forum.java.sun.com/thread.jspa?threadID=788017
You should:
1. Open connection
2.Open statement
3.Get ResultSet
4.Convert ResultSet into something better
5. close ResultSet
6.close statement
7.close connection
8. return the "something better you converted the ResultSet into"
Of course 5,6,7 should be coded in a way they ALWAYS get executed regardless of any exception may occur (for example in finally block).
1 to 8 may also be replaced by (unless your purpose is only to learn JDBC basics):
1. use some kind of high level framework/library/standard (Hibernate,Ibatis,JPA if you use Java 1.5+... you name it, there are as much as you may need, or maybe even a few more!)
Hope this helps,
Riccardo

Maximum open cursors exceeded from Oracle XA Connection pool

I am on WLS 6.1 sp2.
When i leave the server up overnight unaccessed and come back and see in the morning,
I see the following stacktrace on the server console.
I dont think its causing any harm, but is there anyway to prevent this from occuring?
java.sql.SQLException: ORA-01000: maximum open cursors exceeded
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:168)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:208)
at oracle.jdbc.ttc7.Oopen.receive(Oopen.java:118)
at oracle.jdbc.ttc7.TTC7Protocol.open(TTC7Protocol.java:466)
at oracle.jdbc.driver.OracleStatement.<init>(OracleStatement.java:413)
at oracle.jdbc.driver.OracleStatement.<init>(OracleStatement.java:432)
at oracle.jdbc.driver.OraclePreparedStatement.<init>(OraclePreparedStatement.java:182)
at oracle.jdbc.driver.OracleCallableStatement.<init>(OracleCallableStatement.java:102)
at oracle.jdbc.driver.OracleCallableStatement.<init>(OracleCallableStatement.java:86)
at oracle.jdbc.driver.OracleConnection.privatePrepareCall(OracleConnection.java:736)
at oracle.jdbc.driver.OracleConnection.prepareCall(OracleConnection.java:622)
at oracle.jdbc.xa.client.OracleXAResource.start(OracleXAResource.java:163)
at weblogic.jdbc.jta.VendorXAResource.start(VendorXAResource.java:41)
at weblogic.transaction.internal.ServerResourceInfo.start(ServerResourceInfo.java:1032)
at weblogic.transaction.internal.ServerResourceInfo.xaStart(ServerResourceInfo.java:975)
at weblogic.transaction.internal.ServerResourceInfo.enlist(ServerResourceInfo.java:234)
at weblogic.transaction.internal.ServerTransactionImpl.enlistResource(ServerTransactionImpl.java:374)
at weblogic.jdbc.common.internal.ConnectionEnv.test(ConnectionEnv.java:937)
at weblogic.common.internal.ResourceAllocator.reserve(ResourceAllocator.java:465)
at weblogic.common.internal.ResourceAllocator.reserveUnused(ResourceAllocator.java:376)
at weblogic.common.internal.ResourceAllocator.trigger(ResourceAllocator.java:1103)
at weblogic.time.common.internal.ScheduledTrigger.executeLocally(ScheduledTrigger.java:238)
at weblogic.time.common.internal.ScheduledTrigger.execute(ScheduledTrigger.java:229)
at weblogic.time.server.ScheduledTrigger.execute(ScheduledTrigger.java:65)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)

Hi. I think this is an oracle driver problem, in all likelihood.
We test a connection with:
Statement stmt = c.createStatement();
stmt.execute(sql);
Where the string sql is "select count(*) from DUAL" if you named your test table as 'DUAL'.
We obtain no result set, so the driver shouldn't be accruing cursors...
Can you upgrade to the latest oracle driver?
Can you upgrade to the latest version of 6.1?
Jeeva wrote:
I am on WLS 6.1 sp2.
When i leave the server up overnight unaccessed and come back and see in the morning,
I see the following stacktrace on the server console.
I dont think its causing any harm, but is there anyway to prevent this from occuring?
java.sql.SQLException: ORA-01000: maximum open cursors exceeded
at oracle.jdbc.dbaccess.DBError.throwSqlException(DBError.java:168)
at oracle.jdbc.ttc7.TTIoer.processError(TTIoer.java:208)
at oracle.jdbc.ttc7.Oopen.receive(Oopen.java:118)
at oracle.jdbc.ttc7.TTC7Protocol.open(TTC7Protocol.java:466)
at oracle.jdbc.driver.OracleStatement.<init>(OracleStatement.java:413)
at oracle.jdbc.driver.OracleStatement.<init>(OracleStatement.java:432)
at oracle.jdbc.driver.OraclePreparedStatement.<init>(OraclePreparedStatement.java:182)
at oracle.jdbc.driver.OracleCallableStatement.<init>(OracleCallableStatement.java:102)
at oracle.jdbc.driver.OracleCallableStatement.<init>(OracleCallableStatement.java:86)
at oracle.jdbc.driver.OracleConnection.privatePrepareCall(OracleConnection.java:736)
at oracle.jdbc.driver.OracleConnection.prepareCall(OracleConnection.java:622)
at oracle.jdbc.xa.client.OracleXAResource.start(OracleXAResource.java:163)
at weblogic.jdbc.jta.VendorXAResource.start(VendorXAResource.java:41)
at weblogic.transaction.internal.ServerResourceInfo.start(ServerResourceInfo.java:1032)
at weblogic.transaction.internal.ServerResourceInfo.xaStart(ServerResourceInfo.java:975)
at weblogic.transaction.internal.ServerResourceInfo.enlist(ServerResourceInfo.java:234)
at weblogic.transaction.internal.ServerTransactionImpl.enlistResource(ServerTransactionImpl.java:374)
at weblogic.jdbc.common.internal.ConnectionEnv.test(ConnectionEnv.java:937)
at weblogic.common.internal.ResourceAllocator.reserve(ResourceAllocator.java:465)
at weblogic.common.internal.ResourceAllocator.reserveUnused(ResourceAllocator.java:376)
at weblogic.common.internal.ResourceAllocator.trigger(ResourceAllocator.java:1103)
at weblogic.time.common.internal.ScheduledTrigger.executeLocally(ScheduledTrigger.java:238)
at weblogic.time.common.internal.ScheduledTrigger.execute(ScheduledTrigger.java:229)
at weblogic.time.server.ScheduledTrigger.execute(ScheduledTrigger.java:65)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)

In java/jsp got Error,ORA-01000: maximum open cursors exceeded,

Dear ALL,
We are facing a problem of in java/jsp. ORA-01000: maximum open cursors exceeded,We are using referance Cursor for returing the Record in java file.
The Code is given below.
import java.sql.*;
import javax.sql.*;
import com.india.trade.dbConnection.*;
import oracle.jdbc.driver.*;
import java.util.Vector ;
public class IntRmsActivity
     private static JDBCConnection instance = null;
private static Connection con = null;
     private static CallableStatement stmt_admin_getadmins = null;
     private static String str_admin_getadmins = "{ call Admin_conf.RMS_ADMIN_GETALLADMINS(?,?) }";
     static
          try
               instance = new JDBCConnection();
               con = instance.getConnection();
               stmt_admin_getadmins = con.prepareCall(str_admin_getadmins);
}catch(Exception se){se.printStackTrace();}
     public static Vector admin_getAdmins() throws Exception
          checkconnection();
          String message = null;
          Vector v_admins = new Vector();
          ResultSet rs_admins = null;
          stmt_admin_getadmins.registerOutParameter(1 , OracleTypes.CURSOR);
          stmt_admin_getadmins.registerOutParameter(2 , Types.VARCHAR);
          stmt_admin_getadmins.execute();
          message = stmt_admin_getadmins.getString(2);
          System.out.println("message " + message);
          rs_admins = ((OracleCallableStatement)stmt_admin_getadmins).getCursor(1);
          while (rs_admins.next())
                    v_admins.addElement(rs_admins.getString("adminid"));
          rs_admins.close();
          return v_admins;
CREATE OR REPLACE PACKAGE Admin_conf IS
TYPE REF_CRSR IS REF CURSOR; /* OUTPUT CURSOR VARIABLE TYPE */
PROCEDURE RMS_ADMIN_GETALLADMINS(RESULTS OUT REF_CRSR,
                                        OUT_MESSAGE OUT VARCHAR2);
END Admin_conf;
CREATE OR REPLACE PACKAGE BODY Admin_conf
IS
PROCEDURE RMS_ADMIN_GETALLADMINS(RESULTS OUT REF_CRSR,
                                        OUT_MESSAGE OUT VARCHAR2)
IS
l_ref_out_crsr REF_CRSR;
BEGIN
     OPEN l_ref_out_crsr FOR
     SELECT EXECUTIVE_ID adminid
     FROM MASTER_EXECUTIVE_ID
     ORDER BY EXECUTIVE_ID;
     OUT_MESSAGE := 'ADMIN IDS FETCHED SUCCESSFULLY';
     RESULTS := l_ref_out_crsr;
EXCEPTION WHEN OTHERS THEN
          OUT_MESSAGE := 'ERROR ' || SUBSTR(SQLERRM, 1, 60);
END RMS_ADMIN_GETALLADMINS;
END Admin_conf;
Regards
Ajay Singh Rathod

Are you actually closing the connections, resultsets in all cases?
From what you've posted you call
rs_admins.close();but in that method, you propagate any exceptions that occur out to the caller method, which in turn just prints a stack trace.
So if an exception occurs before you call the rs_admin.close() the result set will never be closed as the statement won't be reached.
I'd add a speific exception handling routine to the admin_getAdmins() method and include a finally clause to close the result set in all cases. You can still onthrow the exception if you want.
cheers
-steve-

JDBC & Open Cursors

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