26. 02. 2019.

Impact of the JVM Garbage Collector on the realistic workload

At the last regional Java and Open Source conference where I held the presentation named: “Java Mission Control now in OpenJDK – best practice”, several questions have been raised about a way of testing JEE apps, influence of a GC (Garbage Collector) on the overall performance, new GC engines etc. With OpenJDK 11 we have […]

19. 02. 2019.

Bulk collect and memory limits

We all know that for bulk collect PL/SQL operation it’s important to keep the memory consumption under control. For that reason all bulk collect operations should be combined with a LIMIT clause like in the following code fragment: Setting the limit to process only 10K records in bulk is does not impress me in a […]

28. 01. 2019.

Easy way to create Virtualbox VM’s internal network

Virtualbox is a very popular hypervisor which allows you to run guest virtual machines like Windows, Linux, BSD, Solaris etc. For various purposes you might want to combine several virtual machines into one network. In this post I’ll describe the easiest way of how to do that, which is good enough for most of the […]

18. 01. 2019.

Python as bash replacement

Even today, on many projects I can still find that many developers are still using bash & Korn shell or even Pro*C as a main tool for developing scripts that will be executed as part of batch job in one of the following ways: Unix/Linux cron Oracle’s dbms_job / dbms_scheduler commercial enterprise job scheduling software […]

04. 01. 2019.

Multipath I/O and Network bonding

Event though Multipath I/O and NIC bonding is more related to sysadmin and storage admin tasks, it is good idea to grab some knowledge about those keywords as they play important role in achieving good performance. In the series of articles about disk speed I explained why it is good to know what values you […]

07. 12. 2018.

Oracle Forms 12c client deployment configuration options

Many Oracle users are still considering Oracle Forms/Reports as the best UI technology Oracle has to offer. It’s not surprising as Forms/Reports technology is very robust, developed through the decades, has proved in many large projects as very reliable and fast technology that leverage three-tier architecture (unlike Oracle APEX, very popular these days for building […]

16. 08. 2018.

Exadata / Linux crash – capturing kernel dump on Linux systems

This article has been motivated from real life issue experienced on Exadata system running a few dozen of Oracle databases. I have already written about Exadata shortcoming in one of previous articles where I stressed that one of the main disadvantages of Exadata machine is non-existent virtualization technology. Oracle recognizes Oracle VM as the only […]

28. 07. 2018.

Supplemental logging – when to use it (and when not)

Supplemental logging feature along with streaming and CDC (change data capture) is available for a long time and is used mainly as one of the integration options especially for loading data from transactional (OLTP) into DW (Data Warehouse) staging tables. During my engagement on project for one large retailer, I noticed significant performance penalties due […]

27. 05. 2018.

Exadata shortcomings Part 2

Flexibility   Flexibiliy is a weak point in case of Exacloud also that I tested last year (you can found on this site). Exadata is delivered with pre installed and configured SW and 2 node cluster. It’s true that you can destroy it and customize, but that’s not the point (in that case it’s much […]

27. 05. 2018.

Exadata shortcomings Part 1

It’s very difficult to write about Exadata Appliance, the famous jewel in the Oracle offering, machine that combine HW and SW that are engineered to work together. There is no point to repeat what you can already know or find in books, web or wherever. On the other side, rarely you can find that someone […]