Vivek Agarwal’s Portal/Java Blog

An IBM Gold Consultant’s weblog about IBM, Lotus, WebSphere, J2EE, IT Processes, and other IT technologies

Archive for the ‘Oracle’ Category

Firewall dropping Oracle database connections in WebSphere connection pool?

Posted by Vivek Agarwal on July 4, 2009

We recently switched one of our client’s WebSphere Application Server and WebSphere Portal based infrastructure to a new physical environment. During our testing we found that we were getting stale connection exceptions in SystemOut.log and in the application logs. On digging a little deeper, our team tracked it down to the fact that the Cisco firewall was dropping our Oracle database connections after they had been inactive for a certain amount of time. When our team discussed the issue with the network team, they were essentially told that all was good with the network infrastructure. The application team tweaked some of the connection pool settings but that only helped alleviate the issue slightly and we started encountering performance issues. Eventually, we figured out a solution that works!

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Posted in Java, Oracle, WebSphere | Tagged: , , , | 13 Comments »

Oracle database does not start up automatically!

Posted by Vivek Agarwal on July 24, 2008

Today I had to go in to configure multi-master replication between two Oracle databases as our Oracle replication expert was out at a client site. Well, to set up replication, I had to first connect to the database instances, and I found that one of the two instances was not starting up automatically even though the Windows service for that instance was started. I remembered that this was a problem that I had to run into a couple of years back but it took me a bit to figure out the core issue and resolve it. So I figured, I might as blog about it in case I run into it again a few years down the road and need to resolve the issue again.

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Posted in Oracle | Tagged: | 6 Comments »

Getting past issues with reverse engineering an Oracle schema with Visio on Vista

Posted by Vivek Agarwal on December 14, 2007

Yesterday, I had the need to reverse engineer an Oracle schema in Microsoft Visio on my now not-so-new Vista laptop. While I had the Oracle JDBC drivers copied onto my Vista laptop, I did not have the Oracle client installed. I first tried to install the Oracle 9i client, because the Oracle schema was in a Oracle 9i database instance. The Oracle 9i client installer warns about incompatibility with Vista and it certainly lived up to the billing. I saw several other users with postings about issues. I saw one obvious issue with folder permissions and changed ownership/permissions on the Oracle client install folder, but that did not resolve the issue all the way. While trying to configure an ODBC data source (only for reverse engineering the Oracle schema) , I ran into errors that had again been encountered by many. The first error was “The setup routines for the oracle in orahome92 odbc driver could not be loaded due to system error code 126”. Clicking ok on this error resulted in a secondary error alert – “Could not load the setup or translator library”. At this point, rather than spend more cycles on the issue, I switched to reverse engineering the schema using the eclipse plugin – Clay. Clay worked just fine for reverse engineering the schema (took all of 5 minutes), but the issue with it was that it did not allow me to move the foreign key connectors to make them route better. At this point, I was back looking at the Visio route and the solution was extremely simple! Read the rest of this entry »

Posted in Oracle, Vista, Windows Vista | Tagged: , , , , | 1 Comment »

How to determine row count for all tables in an Oracle Schema?

Posted by Vivek Agarwal on July 17, 2007

If you ever need to determine the row count for all tables in an Oracle Schema as I did, here is something to help you out. Read the rest of this entry »

Posted in Oracle | 11 Comments »

How to detect a duplicate row in an Oracle database table?

Posted by Vivek Agarwal on July 9, 2007

Recently I ran into the situation where I knew that an Oracle database table had a duplicate row, and needed to detect the duplicate row so that I could resolve the situation. You might say that the database design could and should enforce a uniqueness constraint to prevent this situation and you would be right – however given the situation how do you detect the duplicate row? Read the rest of this entry »

Posted in Oracle | Comments Off on How to detect a duplicate row in an Oracle database table?