Re: mysteriously dying connections (Oracle - tomcat)
i checked this over and over again. i really do return all the connetions. - Original Message - From: Ralph Einfeldt [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, June 21, 2001 5:30 PM Subject: AW: mysteriously dying connections (Oracle - tomcat) It sounds to me like you're not alway returning the connection to the pool or not closing the connection. But this is hard to say without the source of your java class. If you use a connection pool where you have access to the source code, look if the get and release methods can be intrumented in a way to log each get and release with the hashcode of the connection. Otherwise log each call to get/release in your own code or build a wrapper object around the pool that log this information before calling the pool method. -Ursprüngliche Nachricht- Von: Lukas Sägesser [mailto:[EMAIL PROTECTED]] Gesendet: Donnerstag, 21. Juni 2001 16:38 An: [EMAIL PROTECTED] Betreff: mysteriously dying connections (Oracle - tomcat) hi all! problem: database access is managed via a java class that is instantiated and loaded into each clients session. every PL/SQL function and/or SQL statement a client needs is called in a method of this class. first, a connection is opened, the statement is called, all resultsets and statements are closed and finally the connection is closed. (or returned back to the connection pool if one is used) the driver we use is the Oracle jdbc ThinDriver (jdbc driver type 4). after running the system for several days, dead connections (and as we just discovered, tons of open cursors) pile up. eventually the webserver(tomcat) will crash or just hang. in the process, access gets slower and slower, there may be delays of 3 minutes until the webserver (or, perhaps the database, in which case the webserver would be just waiting for the db..) gives a response. after a restart of the webserver or the database or both, the system runns very well again. we tried several connection pools. with these, there were no delays for getting a connection, but the pool threw timeoutExceptions (i.e. made it visible that there are hanging connections) and after a few hundred timeouts the VM crashed with a stack overflow. the connections seem to get killed/kill themselfes randomly no matter which function was called. we log the methods and statements that were called for the connections that die, but there is just no pattern in it. thats why we dont find the root of the problem.. is it the driver ? the database ? the tomcat ? environment: Web Server: Suse Linux 7.2 Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL DB Server: Suse Linux 7.2 Oracle 8i 8.1.7 /w multi-threaded server (MTS) Backup Server: Oracle Shadow server things done: - linux update - apache update - tomcat update - jdbc thin driver update (everywhere the newest version) - tried several connection pools possible changes: - - use OCI drivers instead of thin driver - use J-serv with GNU_jsp instead of tomcat every help is welcome, we're frustrated to no ends. thanks very much in advance!! l.sägesser
AW: mysteriously dying connections (Oracle - tomcat)
you can also look in V$SESSIONS or under unix with netstat -a | grep 1521 how many connections are established. regards, tom -Ursprüngliche Nachricht- Von: Lukas Sägesser [mailto:[EMAIL PROTECTED]] Gesendet: Freitag, 22. Juni 2001 11:59 An: [EMAIL PROTECTED] Betreff: Re: mysteriously dying connections (Oracle - tomcat) i checked this over and over again. i really do return all the connetions. - Original Message - From: Ralph Einfeldt [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, June 21, 2001 5:30 PM Subject: AW: mysteriously dying connections (Oracle - tomcat) It sounds to me like you're not alway returning the connection to the pool or not closing the connection. But this is hard to say without the source of your java class. If you use a connection pool where you have access to the source code, look if the get and release methods can be intrumented in a way to log each get and release with the hashcode of the connection. Otherwise log each call to get/release in your own code or build a wrapper object around the pool that log this information before calling the pool method. -Ursprüngliche Nachricht- Von: Lukas Sägesser [mailto:[EMAIL PROTECTED]] Gesendet: Donnerstag, 21. Juni 2001 16:38 An: [EMAIL PROTECTED] Betreff: mysteriously dying connections (Oracle - tomcat) hi all! problem: database access is managed via a java class that is instantiated and loaded into each clients session. every PL/SQL function and/or SQL statement a client needs is called in a method of this class. first, a connection is opened, the statement is called, all resultsets and statements are closed and finally the connection is closed. (or returned back to the connection pool if one is used) the driver we use is the Oracle jdbc ThinDriver (jdbc driver type 4). after running the system for several days, dead connections (and as we just discovered, tons of open cursors) pile up. eventually the webserver(tomcat) will crash or just hang. in the process, access gets slower and slower, there may be delays of 3 minutes until the webserver (or, perhaps the database, in which case the webserver would be just waiting for the db..) gives a response. after a restart of the webserver or the database or both, the system runns very well again. we tried several connection pools. with these, there were no delays for getting a connection, but the pool threw timeoutExceptions (i.e. made it visible that there are hanging connections) and after a few hundred timeouts the VM crashed with a stack overflow. the connections seem to get killed/kill themselfes randomly no matter which function was called. we log the methods and statements that were called for the connections that die, but there is just no pattern in it. thats why we dont find the root of the problem.. is it the driver ? the database ? the tomcat ? environment: Web Server: Suse Linux 7.2 Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL DB Server: Suse Linux 7.2 Oracle 8i 8.1.7 /w multi-threaded server (MTS) Backup Server: Oracle Shadow server things done: - linux update - apache update - tomcat update - jdbc thin driver update (everywhere the newest version) - tried several connection pools possible changes: - - use OCI drivers instead of thin driver - use J-serv with GNU_jsp instead of tomcat every help is welcome, we're frustrated to no ends. thanks very much in advance!! l.sägesser
Re: mysteriously dying connections (Oracle - tomcat)
Make sure your developers properly close resultsets and statements. It could be that they remain open after exceptions. Make sure you have the closing statements in the finally section of try/catch/finally. hth * * Boris NiyazovPh: 212-854-4094 Fax: 212-854-1749 * * Systems Manager Email: [EMAIL PROTECTED] * * Columbia Law School URL: http://www.law.columbia.edu * * hi all! problem: database access is managed via a java class that is instantiated and loaded into each clients session. every PL/SQL function and/or SQL statement a client needs is called in a method of this class. first, a connection is opened, the statement is called, all resultsets and statements are closed and finally the connection is closed. (or returned back to the connection pool if one is used) the driver we use is the Oracle jdbc ThinDriver (jdbc driver type 4). after running the system for several days, dead connections (and as we just discovered, tons of open cursors) pile up. eventually the webserver(tomcat) will crash or just hang. in the process, access gets slower and slower, there may be delays of 3 minutes until the webserver (or, perhaps the database, in which case the webserver would be just waiting for the db..) gives a response. after a restart of the webserver or the database or both, the system runns very well again. we tried several connection pools. with these, there were no delays for getting a connection, but the pool threw timeoutExceptions (i.e. made it visible that there are hanging connections) and after a few hundred timeouts the VM crashed with a stack overflow. the connections seem to get killed/kill themselfes randomly no matter which function was called. we log the methods and statements that were called for the connections that die, but there is just no pattern in it. thats why we dont find the root of the problem.. is it the driver ? the database ? the tomcat ? environment: Web Server: Suse Linux 7.2 Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL DB Server: Suse Linux 7.2 Oracle 8i 8.1.7 /w multi-threaded server (MTS) Backup Server: Oracle Shadow server things done: - linux update - apache update - tomcat update - jdbc thin driver update (everywhere the newest version) - tried several connection pools possible changes: - - use OCI drivers instead of thin driver - use J-serv with GNU_jsp instead of tomcat every help is welcome, we're frustrated to no ends. thanks very much in advance!! l.sägesser - Boris
mysteriously dying connections (Oracle - tomcat)
hi all! problem: database access is managed via a java class that is instantiated and loaded into each clients session. every PL/SQL function and/or SQL statement a client needs is called in a method of this class. first, a connection is opened, the statement is called, all resultsets and statements are closed and finally the connection is closed. (or returned back to the connection pool if one is used) the driver we use is the Oracle jdbc ThinDriver (jdbc driver type 4). after running the system for several days, dead connections (and as we just discovered, tons of open cursors) pile up. eventually the webserver(tomcat) will crash or just hang. in the process, access gets slower and slower, there may be delays of 3 minutes until the webserver (or, perhaps the database, in which case the webserver would be just waiting for the db..) gives a response. after a restart of the webserver or the database or both, the system runns very well again. we tried several connection pools. with these, there were no delays for getting a connection, but the pool threw timeoutExceptions (i.e. made it visible that there are hanging connections) and after a few hundred timeouts the VM crashed with a stack overflow. the connections seem to get killed/kill themselfes randomly no matter which function was called. we log the methods and statements that were called for the connections that die, but there is just no pattern in it. thats why we dont find the root of the problem.. is it the driver ? the database ? the tomcat ? environment: Web Server: Suse Linux 7.2 Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL DB Server: Suse Linux 7.2 Oracle 8i 8.1.7 /w multi-threaded server (MTS) Backup Server: Oracle Shadow server things done: - linux update - apache update - tomcat update - jdbc thin driver update (everywhere the newest version) - tried several connection pools possible changes: - - use OCI drivers instead of thin driver - use J-serv with GNU_jsp instead of tomcat every help is welcome, we're frustrated to no ends. thanks very much in advance!! l.sägesser
Re: mysteriously dying connections (Oracle - tomcat)
Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with Two Sun Sparc Solaris 7 Servers both tomcat 3.2.1 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) --- As you can see between 07:41:23 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException at shopmanager.init(shopmanager.java:16) at shop1.init(shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:797) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@2c7887, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:224) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ContextManager: Removing context Ctx( /examples ) 5:01:12 was the time where I shutdowned the tomcat server I now shutdown/restart the server hourly and it seems we don't have unsheduled stoppings. Another thing is, that the servlets dont get refreshed when they are changed/deleted (I have reload in server.xml).. Thanks jan ~| ~|problem: ~| ~| ~|database access is managed via a java class that is ~|instantiated and loaded into each clients session. every ~|PL/SQL function and/or SQL statement a client needs is ~|called in a method of this class. ~|first, a connection is opened, the statement is called, ~|all resultsets and statements are closed and finally the ~|connection is closed. (or returned back to the ~|connection pool if one is used) ~| ~|the driver we use is the Oracle jdbc ThinDriver (jdbc ~|driver type 4). after running the system for several ~|days, dead connections (and as we just discovered, tons ~|of open cursors) pile up. ~|eventually the webserver(tomcat) will crash or just ~|hang. ~|in the process, access gets slower and slower, there may ~|be delays of 3 minutes until the webserver (or, perhaps ~|the database, in which case the webserver would be just ~|waiting for the db..) gives a response. ~|after a restart of the webserver or the database or ~|both, the system runns very well again. ~| ~|we tried several connection pools. with these, there ~|were no delays for getting a connection, but the pool ~|threw timeoutExceptions (i.e. made it visible that there ~|are hanging connections) and after a few hundred ~|timeouts the VM crashed with a stack overflow. ~| ~|the connections seem to get killed/kill themselfes ~|randomly no matter which function was called. we log the ~|methods and statements that were called for the ~|connections that die, but there is just no pattern in ~|it. thats why we dont find the root of the problem.. is ~|it the driver ? the database ? the tomcat ? ~| ~| ~| ~|environment: ~| ~| ~|Web Server: ~|Suse Linux 7.2 ~|Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL ~| ~|DB Server: ~|Suse Linux 7.2 ~|Oracle 8i 8.1.7 /w multi-threaded server (MTS) ~| ~|Backup Server: ~|Oracle Shadow server ~| ~| ~| ~|things done:
RE: mysteriously dying connections (Oracle - tomcat)
These look like two different issues: 1) Oracle is running out of cursors. a) Make sure you close every ResultSet, Statement and Connection when you're done with them. One trick you can use on Oracle is to log into the database in SQL*Plus as SYS while your application is running, and do, SELECT SQL_TEXT FROM V_$OPEN_CURSOR; to see the SQL for the cursors you have open. b) Try reusing connections and (prepared) statements wherever possible (assuming you use a common Oracle logon for all your accesses). c) Up the number of allowed open cursors, by putting open_cursors = 500 or so in your database's init.ora file. 2) Tomcat is running out of threads. Are you actually getting dozens of people connecting at the same time? Try increasing the max_threads parameter for PoolTcpConnector in your server.xml. -- Bill K. -Original Message- From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:16 AM To: [EMAIL PROTECTED] Subject: Re: mysteriously dying connections (Oracle - tomcat) Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with Two Sun Sparc Solaris 7 Servers both tomcat 3.2.1 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) --- As you can see between 07:41:23 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException at shopmanager.init(shopmanager.java:16) at shop1.init(shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:79 7) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpC onnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@2c7887, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:224) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ContextManager: Removing context Ctx( /examples ) 5:01:12 was the time where I shutdowned the tomcat server I now shutdown/restart the server hourly and it seems we don't have unsheduled stoppings. Another thing is, that the servlets dont get refreshed when they are changed/deleted (I have reload in server.xml).. Thanks jan ~| ~|problem: ~| ~| ~|database access is managed via a java class that is ~|instantiated and loaded into each clients session. every ~|PL/SQL function and/or SQL statement a client needs is ~|called in a method of this class. ~|first, a connection is opened, the statement is called, ~|all resultsets and statements are closed and finally the ~|connection is closed. (or returned back to the ~|connection pool if one is used) ~| ~|the driver we use is the Oracle jdbc ThinDriver (jdbc ~|driver type 4). after running the system for several ~|days, dead connections (and as we just discovered, tons ~|of open cursors) pile up. ~|eventually the webserver(tomcat) will crash or just ~|hang. ~|in the process, access gets slower and slower, there may ~|be delays of 3 minutes until the webserver
RE: mysteriously dying connections (Oracle - tomcat)
Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema. Using the DBA Studio, I looked through all the schemas and users and V_$OPEN_CURSOR doesn't exist anywhere. Would it be under an alternative name? - Adam At 08:32 AM 6/21/2001 -0700, you wrote: These look like two different issues: 1) Oracle is running out of cursors. a) Make sure you close every ResultSet, Statement and Connection when you're done with them. One trick you can use on Oracle is to log into the database in SQL*Plus as SYS while your application is running, and do, SELECT SQL_TEXT FROM V_$OPEN_CURSOR; to see the SQL for the cursors you have open. b) Try reusing connections and (prepared) statements wherever possible (assuming you use a common Oracle logon for all your accesses). c) Up the number of allowed open cursors, by putting open_cursors = 500 or so in your database's init.ora file. 2) Tomcat is running out of threads. Are you actually getting dozens of people connecting at the same time? Try increasing the max_threads parameter for PoolTcpConnector in your server.xml. -- Bill K. -Original Message- From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:16 AM To: [EMAIL PROTECTED] Subject: Re: mysteriously dying connections (Oracle - tomcat) Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with Two Sun Sparc Solaris 7 Servers both tomcat 3.2.1 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) --- As you can see between 07:41:23 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException at shopmanager.init(shopmanager.java:16) at shop1.init(shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:79 7) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpC onnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@2c7887, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:224) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ContextManager: Removing context Ctx( /examples ) 5:01:12 was the time where I shutdowned the tomcat server I now shutdown/restart the server hourly and it seems we don't have unsheduled stoppings. Another thing is, that the servlets dont get refreshed when they are changed/deleted (I have reload in server.xml).. Thanks jan ~| ~|problem: ~| ~| ~|database access is managed via a java class that is ~|instantiated and loaded into each clients session. every ~|PL/SQL function and/or SQL statement a client needs is ~|called in a method of this class. ~|first, a connection is opened, the statement is called, ~|all resultsets and statements are closed and finally the ~|connection is closed. (or returned back to the ~|connection pool if one is used) ~| ~|the driver we use is the Oracle jdbc ThinDriver (jdbc ~|driver type 4). after running the system
RE: mysteriously dying connections (Oracle - tomcat)
Eh,... It might have a different name on your version of Oracle, or be under a different schema. Try running, SELECT OWNER, VIEW_NAME FROM ALL_VIEWS WHERE VIEW_NAME LIKE '%OPEN%CURSOR%'; and see what pops up. -- Bill K. -Original Message- From: Adam Myatt [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:54 AM To: [EMAIL PROTECTED] Subject: RE: mysteriously dying connections (Oracle - tomcat) Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema. Using the DBA Studio, I looked through all the schemas and users and V_$OPEN_CURSOR doesn't exist anywhere. Would it be under an alternative name? - Adam At 08:32 AM 6/21/2001 -0700, you wrote: These look like two different issues: 1) Oracle is running out of cursors. a) Make sure you close every ResultSet, Statement and Connection when you're done with them. One trick you can use on Oracle is to log into the database in SQL*Plus as SYS while your application is running, and do, SELECT SQL_TEXT FROM V_$OPEN_CURSOR; to see the SQL for the cursors you have open. b) Try reusing connections and (prepared) statements wherever possible (assuming you use a common Oracle logon for all your accesses). c) Up the number of allowed open cursors, by putting open_cursors = 500 or so in your database's init.ora file. 2) Tomcat is running out of threads. Are you actually getting dozens of people connecting at the same time? Try increasing the max_threads parameter for PoolTcpConnector in your server.xml. -- Bill K. -Original Message- From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:16 AM To: [EMAIL PROTECTED] Subject: Re: mysteriously dying connections (Oracle - tomcat) Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with Two Sun Sparc Solaris 7 Servers both tomcat 3.2.1 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) --- As you can see between 07:41:23 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException at shopmanager.init(shopmanager.java:16) at shop1.init(shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:7 9 7) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(Http C onnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@2c7887, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:224) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ContextManager: Removing context Ctx( /examples ) 5:01:12 was the time where I shutdowned the tomcat server I now shutdown/restart the server hourly and it seems we don't have unsheduled stoppings. Another thing is, that the servlets dont get refreshed when they are changed/deleted (I have reload in server.xml).. Thanks jan ~| ~|problem: ~| ~| ~|database access
RE: mysteriously dying connections (Oracle - tomcat)
Title: RE: mysteriously dying connections (Oracle - tomcat) you can use v$parameter view for getting OPEN_CURSORS paremeter value. or in sql plus or svrmgrl type show parameter OPEN_CURSORS -Original Message- From: William Kaufman [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 7:12 PM To: '[EMAIL PROTECTED]' Subject: RE: mysteriously dying connections (Oracle - tomcat) Eh,... It might have a different name on your version of Oracle, or be under a different schema. Try running, SELECT OWNER, VIEW_NAME FROM ALL_VIEWS WHERE VIEW_NAME LIKE '%OPEN%CURSOR%'; and see what pops up. -- Bill K. -Original Message- From: Adam Myatt [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:54 AM To: [EMAIL PROTECTED] Subject: RE: mysteriously dying connections (Oracle - tomcat) Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema. Using the DBA Studio, I looked through all the schemas and users and V_$OPEN_CURSOR doesn't exist anywhere. Would it be under an alternative name? - Adam At 08:32 AM 6/21/2001 -0700, you wrote: These look like two different issues: 1) Oracle is running out of cursors. a) Make sure you close every ResultSet, Statement and Connection when you're done with them. One trick you can use on Oracle is to log into the database in SQL*Plus as SYS while your application is running, and do, SELECT SQL_TEXT FROM V_$OPEN_CURSOR; to see the SQL for the cursors you have open. b) Try reusing connections and (prepared) statements wherever possible (assuming you use a common Oracle logon for all your accesses). c) Up the number of allowed open cursors, by putting open_cursors = 500 or so in your database's init.ora file. 2) Tomcat is running out of threads. Are you actually getting dozens of people connecting at the same time? Try increasing the max_threads parameter for PoolTcpConnector in your server.xml. -- Bill K. -Original Message- From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:16 AM To: [EMAIL PROTECTED] Subject: Re: mysteriously dying connections (Oracle - tomcat) Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with Two Sun Sparc Solaris 7 Servers both tomcat 3.2.1 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) --- As you can see between 07:41:23 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException at shopmanager.init(shopmanager.java:16) at shop1.init(shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:7 9 7) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(Http C onnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@2c7887, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:224) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ContextManager: Removing context Ctx( /examples ) 5:01:12 was the time where I shutdowned the tomcat server I now shutdown/restart the server hourly and it seems we don't have unsheduled stoppings. Another thing is, that the servlets dont get refreshed
RE: mysteriously dying connections (Oracle - tomcat)
All right. I found the sql_text listing in the open cursor view. Is there a sure fire way to have the cursors close when the servlet is done using them. (And if so is using connection pooling and closing the recordset and statement one way?) At 07:33 PM 6/21/2001 +0300, you wrote: you can use v$parameter view for getting OPEN_CURSORS paremeter value. or in sql plus or svrmgrl type show parameter OPEN_CURSORS -Original Message- From: William Kaufman [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 7:12 PM To: '[EMAIL PROTECTED]' tomcat) Eh,... It might have a different name on your version of Oracle, or be under Try running, SELECT OWNER, VIEW_NAME FROM ALL_VIEWS WHERE VIEW_NAME LIKE '%OPEN%CURSOR%'; and see what pops up. -- Bill K.-Original Message- From: Adam Myatt [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:54 AM To: [EMAIL PROTECTED] tomcat) Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema. Using the DBA Studio, I looked through all the schemas and users and V_$OPEN_CURSOR doesn't exist anywhere. Would it be under an alternative name?- Adam At 08:32 AM 6/21/2001 -0700, you wrote: These look like two different issues: 1) Oracle is running out of cursors. a) Make sure you close every ResultSet, Statement and Connection when One trick you can use on Oracle is to log into the database in SQL*Plus as SYS while your application is running, and do, SELECT SQL_TEXT FROM V_$OPEN_CURSOR; to see the SQL for the cursors you have open. b) Try reusing connections and (prepared) statements wherever possible (assuming you use a common Oracle logon for all your accesses). c) Up the number of allowed open cursors, by putting open_cursors = 500 or so in your database's init.ora file. 2) Tomcat is running out of threads. Are you actually getting dozens of people connecting at the same time? parameter for PoolTcpConnector in your server.xml. -- Bill K. -Original Message- From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:16 AM To: [EMAIL PROTECTED] tomcat) Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) --- 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException (shopmanager.java:16) (shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:7 9 7) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(Http C onnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@2c7887, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:224) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 -
AW: mysteriously dying connections (Oracle - tomcat)
It sounds to me like you're not alway returning the connection to the pool or not closing the connection. But this is hard to say without the source of your java class. If you use a connection pool where you have access to the source code, look if the get and release methods can be intrumented in a way to log each get and release with the hashcode of the connection. Otherwise log each call to get/release in your own code or build a wrapper object around the pool that log this information before calling the pool method. -Ursprüngliche Nachricht- Von: Lukas Sägesser [mailto:[EMAIL PROTECTED]] Gesendet: Donnerstag, 21. Juni 2001 16:38 An: [EMAIL PROTECTED] Betreff: mysteriously dying connections (Oracle - tomcat) hi all! problem: database access is managed via a java class that is instantiated and loaded into each clients session. every PL/SQL function and/or SQL statement a client needs is called in a method of this class. first, a connection is opened, the statement is called, all resultsets and statements are closed and finally the connection is closed. (or returned back to the connection pool if one is used) the driver we use is the Oracle jdbc ThinDriver (jdbc driver type 4). after running the system for several days, dead connections (and as we just discovered, tons of open cursors) pile up. eventually the webserver(tomcat) will crash or just hang. in the process, access gets slower and slower, there may be delays of 3 minutes until the webserver (or, perhaps the database, in which case the webserver would be just waiting for the db..) gives a response. after a restart of the webserver or the database or both, the system runns very well again. we tried several connection pools. with these, there were no delays for getting a connection, but the pool threw timeoutExceptions (i.e. made it visible that there are hanging connections) and after a few hundred timeouts the VM crashed with a stack overflow. the connections seem to get killed/kill themselfes randomly no matter which function was called. we log the methods and statements that were called for the connections that die, but there is just no pattern in it. thats why we dont find the root of the problem.. is it the driver ? the database ? the tomcat ? environment: Web Server: Suse Linux 7.2 Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL DB Server: Suse Linux 7.2 Oracle 8i 8.1.7 /w multi-threaded server (MTS) Backup Server: Oracle Shadow server things done: - linux update - apache update - tomcat update - jdbc thin driver update (everywhere the newest version) - tried several connection pools possible changes: - - use OCI drivers instead of thin driver - use J-serv with GNU_jsp instead of tomcat every help is welcome, we're frustrated to no ends. thanks very much in advance!! l.sägesser
RE: mysteriously dying connections (Oracle - tomcat)
whenever you are done with a db call make sure you close _all_ statements (regular,prepared, callable) and _all_ resultsets. these objects are the objects referencing cursors to the database. Filip ~ Namaste - I bow to the divine in you ~ Filip Hanik Software Architect [EMAIL PROTECTED] www.filip.net -Original Message- From: Adam Myatt [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 9:51 AM To: [EMAIL PROTECTED] Subject: RE: mysteriously dying connections (Oracle - tomcat) All right. I found the sql_text listing in the open cursor view. Is there a sure fire way to have the cursors close when the servlet is done using them. (And if so is using connection pooling and closing the recordset and statement one way?) At 07:33 PM 6/21/2001 +0300, you wrote: you can use v$parameter view for getting OPEN_CURSORS paremeter value. or in sql plus or svrmgrl type show parameter OPEN_CURSORS -Original Message- From: William Kaufman [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 7:12 PM To: '[EMAIL PROTECTED]' tomcat) Eh,... It might have a different name on your version of Oracle, or be under Try running, SELECT OWNER, VIEW_NAME FROM ALL_VIEWS WHERE VIEW_NAME LIKE '%OPEN%CURSOR%'; and see what pops up. -- Bill K.-Original Message- From: Adam Myatt [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:54 AM To: [EMAIL PROTECTED] tomcat) Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema. Using the DBA Studio, I looked through all the schemas and users and V_$OPEN_CURSOR doesn't exist anywhere. Would it be under an alternative name?- Adam At 08:32 AM 6/21/2001 -0700, you wrote: These look like two different issues: 1) Oracle is running out of cursors. a) Make sure you close every ResultSet, Statement and Connection when One trick you can use on Oracle is to log into the database in SQL*Plus as SYS while your application is running, and do, SELECT SQL_TEXT FROM V_$OPEN_CURSOR; to see the SQL for the cursors you have open. b) Try reusing connections and (prepared) statements wherever possible (assuming you use a common Oracle logon for all your accesses). c) Up the number of allowed open cursors, by putting open_cursors = 500 or so in your database's init.ora file. 2) Tomcat is running out of threads. Are you actually getting dozens of people connecting at the same time? parameter for PoolTcpConnector in your server.xml. -- Bill K. -Original Message- From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 21, 2001 8:16 AM To: [EMAIL PROTECTED] tomcat) Same here but we have the stopping of the tomcatserver very frequently. At the end of the term when the students (aprox 50 working at the same time) got very busy the tomcatserver stoped replying frequently. We have a configuration with 3.2.2 and one Oracle817 Server on Soalris 7 Once I traped this error: -- 2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads. 2001-06-19 09:02:25 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread - java.lang.IllegalStateException at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.j ava:405) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool. java:501) at java.lang.Thread.run(Thread.java:484) --- 09:02:25 (the shutdown of the tomcat server) there was no activity except angry students (times are pm). And this: - 2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 + /servlet/shop1 + null) - java.lang.NullPointerException (shopmanager.java:16) (shop1.java:14) at java.lang.Class.newInstance0(Native Method) at java.lang.Class.newInstance(Class.java:237) at org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper. java:268) at org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289) at org.apache.tomcat.core.Handler.service(Handler.java:254) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextMana ger.java:7 9 7) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743) at org.apache.tomcat.service.http.HttpConnectionHandler.processConne ction(Http C onnectionHandler.java:210) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.j ava:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool. java:498) at java.lang.Thread.run(Thread.java:484) 2001-06-20 05:01:12 - ThreadPool: Caught exception executing org.apache.tomcat.service.TcpWorkerThread
RE: mysteriously dying connections (Oracle - tomcat)
Is there a sure fire way to have the cursors close when the servlet is
done using them.
I haven't used connection pooling (it's too easy to write your own that does
what you want).
But the only sure-fire way to close your ResultSets and Statements is,...
call the close() method. The safest way to do that is to use try/finally
blocks, like,
Statement stmt = ...;
try
{
ResultSet rs = stmt.executeQuery(...);
try
{
// use the results,...
}
// catch whatever you want here
finally
{
rs.close();
}
}
// catch whatever you want here
finally
{
stmt.close();
}
-- Bill K.
-Original Message-
From: Adam Myatt [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 9:51 AM
To: [EMAIL PROTECTED]
Subject: RE: mysteriously dying connections (Oracle - tomcat)
All right. I found the sql_text listing in the open cursor view. Is there a
sure fire way to have the cursors close when the servlet is done using
them. (And if so is using connection pooling and closing the recordset and
statement one way?)
At 07:33 PM 6/21/2001 +0300, you wrote:
you can use v$parameter view for getting OPEN_CURSORS paremeter value.
or in sql plus or svrmgrl type
show parameter OPEN_CURSORS
-Original Message-
From: William Kaufman [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 7:12 PM
To: '[EMAIL PROTECTED]'
tomcat)
Eh,... It might have a different name on your version of Oracle, or be
under
Try running, SELECT OWNER, VIEW_NAME
FROM ALL_VIEWS
WHERE VIEW_NAME LIKE '%OPEN%CURSOR%'; and see what pops up.
-- Bill K.-Original
Message-
From: Adam Myatt [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 8:54 AM
To: [EMAIL PROTECTED]
tomcat)
Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema.
Using the DBA
Studio, I looked through all the schemas and users and V_$OPEN_CURSOR
doesn't exist anywhere. Would it be under an alternative name?- Adam
At 08:32 AM 6/21/2001 -0700, you wrote:
These look like two different issues:
1) Oracle is running out of cursors.
a) Make sure you close every ResultSet, Statement and Connection when
One trick you can use on Oracle is to log into the
database in SQL*Plus as SYS while your application is running, and do,
SELECT SQL_TEXT FROM V_$OPEN_CURSOR;
to see the SQL for the cursors you have open.
b) Try reusing connections and (prepared) statements wherever possible
(assuming you use a common Oracle logon for all your accesses).
c) Up the number of allowed open cursors, by putting
open_cursors = 500
or so in your database's init.ora file.
2) Tomcat is running out of threads.
Are you actually getting dozens of people connecting at the same time?
parameter for PoolTcpConnector in your
server.xml.
-- Bill K.
-Original Message-
From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 8:16 AM
To: [EMAIL PROTECTED]
tomcat)
Same here but we have the stopping of the tomcatserver very frequently.
At the end of the term when the students (aprox 50 working at the same
time)
got very busy the tomcatserver
stoped replying frequently. We have a configuration with
3.2.2 and one
Oracle817
Server on Soalris 7
Once I traped this error:
--
2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads.
2001-06-19 09:02:25 - ThreadPool: Caught exception executing
org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread -
java.lang.IllegalStateException
at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227)
at
org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405)
at
org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
at java.lang.Thread.run(Thread.java:484)
---
09:02:25 (the shutdown of the tomcat
server) there was no activity except angry students (times are pm).
And this:
-
2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 +
/servlet/shop1 + null) - java.lang.NullPointerException
(shopmanager.java:16)
(shop1.java:14)
at java.lang.Class.newInstance0(Native Method)
at java.lang.Class.newInstance(Class.java:237)
at
org.apache.tomcat.core.ServletWrapper.loadServlet(ServletWrapper.java:268)
at
org.apache.tomcat.core.ServletWrapper.init(ServletWrapper.java:289)
at org.apache.tomcat.core.Handler.service(Handler.java:254)
at
org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372
RE: mysteriously dying connections (Oracle - tomcat)
I do something extremely similar to the code below but at the end I return
the connection to the connection pool. I do not at any tiem use
conn.close()... should I just close the connection instead of using
connection pooling? Would closing the connection instead of returning them
to the pool free up the cursors?
At 11:21 AM 6/21/2001 -0700, you wrote:
Is there a sure fire way to have the cursors close when the servlet is
done using them.
I haven't used connection pooling (it's too easy to write your own that does
what you want).
But the only sure-fire way to close your ResultSets and Statements is,...
call the close() method. The safest way to do that is to use try/finally
blocks, like,
Statement stmt = ...;
try
{
ResultSet rs = stmt.executeQuery(...);
try
{
// use the results,...
}
// catch whatever you want here
finally
{
rs.close();
}
}
// catch whatever you want here
finally
{
stmt.close();
}
-- Bill K.
-Original Message-
From: Adam Myatt [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 9:51 AM
To: [EMAIL PROTECTED]
Subject: RE: mysteriously dying connections (Oracle - tomcat)
All right. I found the sql_text listing in the open cursor view. Is there a
sure fire way to have the cursors close when the servlet is done using
them. (And if so is using connection pooling and closing the recordset and
statement one way?)
At 07:33 PM 6/21/2001 +0300, you wrote:
you can use v$parameter view for getting OPEN_CURSORS paremeter value.
or in sql plus or svrmgrl type
show parameter OPEN_CURSORS
-Original Message-
From: William Kaufman [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 7:12 PM
To: '[EMAIL PROTECTED]'
tomcat)
Eh,... It might have a different name on your version of Oracle, or be
under
Try running, SELECT OWNER, VIEW_NAME
FROM ALL_VIEWS
WHERE VIEW_NAME LIKE '%OPEN%CURSOR%'; and see what pops up.
-- Bill K.-Original
Message-
From: Adam Myatt [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 8:54 AM
To: [EMAIL PROTECTED]
tomcat)
Bill, What if the V_$OPEN_CURSOR is not present in the SYS schema.
Using the DBA
Studio, I looked through all the schemas and users and V_$OPEN_CURSOR
doesn't exist anywhere. Would it be under an alternative name?- Adam
At 08:32 AM 6/21/2001 -0700, you wrote:
These look like two different issues:
1) Oracle is running out of cursors.
a) Make sure you close every ResultSet, Statement and Connection when
One trick you can use on Oracle is to log into the
database in SQL*Plus as SYS while your application is running, and do,
SELECT SQL_TEXT FROM V_$OPEN_CURSOR;
to see the SQL for the cursors you have open.
b) Try reusing connections and (prepared) statements wherever possible
(assuming you use a common Oracle logon for all your accesses).
c) Up the number of allowed open cursors, by putting
open_cursors = 500
or so in your database's init.ora file.
2) Tomcat is running out of threads.
Are you actually getting dozens of people connecting at the same time?
parameter for PoolTcpConnector in your
server.xml.
-- Bill K.
-Original Message-
From: Jan M. STANKOVSKY [mailto:[EMAIL PROTECTED]]
Sent: Thursday, June 21, 2001 8:16 AM
To: [EMAIL PROTECTED]
tomcat)
Same here but we have the stopping of the tomcatserver very frequently.
At the end of the term when the students (aprox 50 working at the same
time)
got very busy the tomcatserver
stoped replying frequently. We have a configuration with
3.2.2 and one
Oracle817
Server on Soalris 7
Once I traped this error:
--
2001-06-19 07:41:23 - ThreadPool: Pool exhausted with 100 threads.
2001-06-19 09:02:25 - ThreadPool: Caught exception executing
org.apache.tomcat.service.TcpWorkerThread@3598c3, terminating thread -
java.lang.IllegalStateException
at org.apache.tomcat.util.ThreadPool.runIt(ThreadPool.java:227)
at
org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:405)
at
org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
at java.lang.Thread.run(Thread.java:484)
---
09:02:25 (the shutdown of the tomcat
server) there was no activity except angry students (times are pm).
And this:
-
2001-06-20 04:51:10 - Ctx( /a9303541 ): Exception in: R( /a9303541 +
/servlet/shop1 + null) - java.lang.NullPointerException
(shopmanager.java:16)
(shop1.java:14)
at java.lang.Class.newInstance0(Native Method)
at java.lang.Class.newInstance(Class.java:237
