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 […]

29. 05. 2018.

Hints and Outlines required action when changing object name

When developing code, usually temporary created objects like tables and indexes have been created just to test some scenario and check behaviour. Very often, in case test passed reside much longer than it was planned. For that reason, at some point in time, it’s needed to change object names to deploy code to upper environments, […]

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 […]

08. 05. 2018.

Oracle tracing mechanism and when not to use it

Quite recently I had to trace/profile an extremely intensive batch job to provide information to Oracle for a further analysis. At very first moment it was obvious that this is a wrong approach and whatever we’ll get, it cannot server as evidence of performance issue that we have, as TKProf is designed to trace single […]

09. 04. 2018.

Resource Manager – internal plan

In this article I’m going to disclose Oracle Resource Manager Internal plan and how it can influence on database performances. Many of Oracle DBA are convinced that Resource Manager is not active, and that RM has to be enabled to be active. To confirm that theory, DBA can execute the following statement: select name, display_value, […]

05. 02. 2018.

Number of columns in RPM Worksheet tables – impact on performance

This time I’ll explain a challenge that I had with optimization of RPM worksheet tables. Even if you have all elements of enterprise architecture tuned, there is still something you can do to speed up the Query or DML operations. Here I’ll present what impact from the physical design you can expect. All examples will […]

26. 12. 2017.

Calling PL/SQL functions from the SQL and it’s influence on query execution

In all books that I red about performance tuning in Oracle (and other major vendor) relational databases, you can find that when optimizing SQL, you remove the select part and concentrate on part starting with FROM clause to inspect what tables have been involved along with the WHERE clause. Recently I have a interesting case […]

01. 11. 2017.

Firefox NPAPI Java Plugin support and Flash support – part 2

Although I already published one article about NPAPI support and Firefox, it is not valid now, as all major web browsers are stop supporting add-ons like Java, Flash and Silverlight in recent versions. Mozilla Firefox in the next version 57, will have no add-ons at all, while the Microsoft Edge from first release has no […]