If you connect to the database through SSH you may come across this message. Error message Server key did not validate in SQL Developer I frequently use SSH to connect to the Oracle database through some jump server. It is straightforward to set up; I blogged about it over six years ago. Today my Windows PC had the BSoD , and after it came back, I had this error when I tried to connect to the database again: ...

I have an excellent career thanks to the Oracle database. For several reasons, I have met many people that support the community by sharing knowledge, and I have learned a lot along the way. One of those things is how to attack troubleshooting and optimization of slow applications. You may know “optimization” as tuning. The Richness of Oracle Database Instrumentation #JoelKallmanDay As a consultant, I have helped in many development projects involving the Oracle database. The Java or C# developers frequently relate to the database with merely superficial knowledge. When they run into a problem, they ask Dr. Google for help. There are, however, some issues with this approach. What comes up on top of a Google search may not be the best solution and might be based on a system configuration or hardware setup quite different from the current project. A better approach is to record what is going on and measure what can be measured. “What can be measured” is not always much. If the developer were proactive, the application would have built-in code for logging and tracing. Quite often, though, the program is a black box that only throws an error message when it crashes. ...

TL;DR: Your merge condition does not uniquely identify one row in the target table. ORA-30926 and MERGE If we ignore bugs that may happen, ORA-30296 comes from a logical error in the merge condition. One row from the source set should match one and only one in the target table, if it exists, in the target. If it matches more than one, the merge statement cannot work as intended, and you need to check what uniquely identifies a row. ...

What is the easiest way to create a table that can have at most one row? That question was asked on Twitter about two days before I intended to blog about my solution, a month ago. Anybody have a suggestion for the best way to ensure that an #oracledatabase table that already has one row can not have another row inserted into it?#sql #plsql — SF on PL/SQL (@sfonplsql) March 2, 2022 My solution is practically the same as what @FranckPachot suggested , but that is not stopping me from blogging mine. ...

Joel Kallman passed away earlier this year. He was one of the first creators of Oracle APEX and always dedicated to the user community. He left a lasting impression on all of us and this is just one post among many written to honour a great guy . For anyone not familiar with Oracle APEX, check out https://apex.oracle.com/ . APEX for Administrators #JoelKallmanDay It is my impression that few DBAs or other administators have much experience with software development. Perhaps that is why they don’t make any tools to help them manage their projects, but resort to general tools like Excel or an internal wiki. This leads to too much time spent on project management and fighting with a tool that is not fit for the task. This is not an issue with a small infrastructure, but if you need to plan downtime for hundreds of databases and their connected applications it can become a logistic nightmare. ...

UTL_HTTP from Autonomous Database The PL/SQL package UTL_HTTP in Oracle Autonomous Databases only allows HTTPS connections. To call secure web services from the database it needs a wallet. The wallet must have the root and intermediate certificates for the remote site. If they are missing you will get the error: ORA-29024: Certificate validation failure But how do you fix that if your database is an autonomous database, like the ADW, or ATP? Turns out, you don’t have to. The wallet that is already set up for you contains about 90 of the most commonly trusted root and intermediate SSL certificates. The only thing you have to do is execute: ...

The last two weeks were shorter than most weeks before. Open for business And with that I mean that time flies when you are busy with something interesting. Finally, I am on my own, and it has been a pleasant experience so far. I have received many encouragements and advice from friends and contacts in the community: Today was my last day at Sysco/Bicon. I am starting in a new role, in my own company. Will do Oracle, development, tuning, data whatever. Feeling good. ...

2020 has been a tough year for many, but I can’t complain considering what other people have gone through. While others lost their job due to the shutdown, I could work from home for extended periods. But I haven’t been satisfied with the way things were going and needed a change. I wanted to focus on what I enjoy doing, and after a checkpoint, I realised what things I wanted to avoid. ...

I don’t know why I stopped blogging, probably because I am lazy or easily distracted. But this annual opportunity to say thanks to some people who has helped me a lot shouldn’t be missed (I did last year). Tim Hall aka ORACLE-BASE organizes an annual virtual Thanksgiving for us Oracle nerds . Expressing gratitude is a strange thing. Why do we say thanks? Frequently we do it just to be polite, but for me, the most honest feeling of gratitude comes after when someone has solved a big problem for me. If I suspect that the person helping me is unaware of how much difference it made, I find it even more important to say “Thank you!” Giving thanks isn’t always easy, the more sincere it is the more awkard it gets. But given this opportunity when a good part of the Oracle community does the same, I have the excuse. So thank you, Tim, for giving us this opportunity (Is this a meta-thank you?) ...

I just upgraded a small Confluent Kafka cluster at a customer. Almost everything went fine, just following these instructions: https://docs.confluent.io/current/installation/upgrade.html (our servers are running on CentOS). But at the end KSQL server wouldn’t start and failed with this error message: [2019-07-11 16:23:31,233] ERROR Failed to start KSQL (io.confluent.ksql.rest.server.KsqlServerMain:53) java.lang.IllegalStateException: Invalid replcation factor on topic _confluent-ksql-default__command_topic: 1 at io.confluent.ksql.rest.util.KsqlInternalTopicUtils.ensureTopic(KsqlInternalTopicUtils.java:91) at io.confluent.ksql.rest.server.KsqlRestApplication.initialize(KsqlRestApplication.java:237) at io.confluent.ksql.rest.server.KsqlRestApplication.startKsql(KsqlRestApplication.java:200) at io.confluent.ksql.rest.server.KsqlRestApplication.start(KsqlRestApplication.java:187) at io.confluent.ksql.rest.server.KsqlServerMain.tryStartApp(KsqlServerMain.java:65) at io.confluent.ksql.rest.server.KsqlServerMain.main(KsqlServerMain.java:51) I checked the replication factor with: ...