Everything our consultants learn while running databases for customers: Oracle, PostgreSQL, SQL Server, MySQL, MariaDB, MongoDB and Delphix. Expect hands-on posts about installation, day-to-day administration, backup and recovery, performance tuning, replication and upgrades.
By Franck Pachot . People often think of indexes as a way to optimize row filtering (“get item” faster and cheaper). But indexes are also about columns (“attribute projection”) like some kind of vertical partitioning. In relational (“SQL”) databases we often add more columns to the indexed key. This is called “covering” or “including” indexes, to avoid reading the whole…
There often is a discussion if tablespaces should be used in PostgreSQL. People used to work with Oracle are often a bit surprised by this discussion as there is no way around using tablespaces in that technology. PostgreSQL does not force you to use tablespaces at all and I am pretty sure that there are plenty of PostgreSQL installations out…
One really good feature from SUSE Linux Enterprise (SLE) is that it allows you to upgrade from your running system to a new service pack online. Let’s say from SLE 12 SP3 to SLE 12 SP4. No new installation is needed. All existing data are kept intact. In the following blog post, I will show you how easy it is.…
By Franck Pachot . This follows the previous post on testing YugaByteDB 2.1 performance with pgbench: https://www.dbi-services.com/blog/yugabytedb-2-1/ A distributed database needs to reduce inter-node synchronization latency and then replaces two-phase pessimistic locking by optimistic concurrency control in many places. This means more serialization errors where a transaction may have to be re-tried. But the PostgreSQL pgbench does not have this…
By Franck Pachot . 9 months ago I was looking at YugaByteDB which was still in beta version for its ‘YSQL’ API. I published my first test on Medium: https://medium.com/@FranckPachot/running-pgbench-on-yugabytedb-1-3-3a15450dfa42. I have been very enthusiastic about the idea, the architecture, the way they open-sourced it and how all was documented in their blog. I’ve even met them in Sunnyvale when…
When you work with databases sooner or later you will need to get in touch witch collations. It might be that you never needed to think about it as initdb picked a value that just worked for you and nobody in your database ever tried to use a collation that is not available in your installation. Once someone is trying…
Earlier this week someone tried to show me how to capture page split events using Extended Events (XE) but unfortunately, the demo failed. This is a good opportunity for me to refresh my knowledge about page split and set up a simple demo about this. Hopefully, this one will be working. It’s not necessarily a bad thing when a page…
Introduction We are back today to write about a powerful tool that we can use to update our folders Question Suppose you have to update two jobs of your folder; the task should be easy But what happens when you must update 50 jobs in a restricted delay? Solution To get this easier and smarter we will use the find…
By Franck Pachot What I want to show in this blog post is that, as in mathematics where you have to apply some algebra rules to transform an equation to an equivalent one, the database developer must translate the business specification to an equivalent that is optimized (in performance, reliability and readability) for the data model. I was looking at…
For a few weeks I was faced with a problem that I had never encountered before. On a Windows Server, browsing to the WebLogic Administration console, I was not able to do any modification or even check the monitoring screens. I always got a message that an error occurred without more explanation. After a new start of the WebLogic Administration…
We are using silent installation to install WebLogic Server software based on a response file with “INSTALL_TYPE=WebLogic Server” but it looks like the coherence server is installed becuase when we start the WebLogic Server, the following can be seen in the WebLogic log files: Oracle Coherence Version 12.2.1.4.0 Build 74888 Grid Edition: Development mode Copyright (c) 2000, 2019, Oracle and/or…
When I write code, I usually need some utility classes to ease the development. So here I will share my most used classes. Hope this will help you as well! XML store and load I strongly use XML for storing configurations or even data, so I made an helper which can store and load any classes (with annotations) as XML,…
