How to identify SQL performing poorly on an APEX application?

Oracle Application Express (APEX) is a great tool to rapidly develop applications on top of an Oracle database. While developing an internal application we noticed that some pages were slow, meaning taking a few seconds to refresh. Suspecting there was some poorly performing SQL behind those pages, we tried to generate a SQL Trace so we could review the generated SQL. Well, there is no out-of-the-box instrumentation to turn SQL Trace ON from an (more...)

Monitor Dell PERC when running on Oracle Virtual Server 3.x

In this article I will try to explain how to monitor your Dell Raid Controller with Cloud Control when running Oracle Virtual server 3.x (OVS3.x).

Some time ago a physical drive broke down on one of our Dell PowerEdge Servers. Not causing any problem because it was configured in a raid set using the Dell build in PowerEdge Raid Controller( hereafter PERC). However, we did not notice this breakdown until also a second (more...)

Commit-Korrekturen mit git

Hat nichts mit Datenbanken zu tun, sondern mit Versionsverwaltung: git benutze ich zwar schon seit einiger Zeit, habe es aber trotz ernsthafter Absichten nie geschafft, mir die Details ausreichend genau anzuschauen, um auf unerwartete Probleme angemessen reagieren zu können. Daher hat mir der Hinweis eines Kollegen auf den Artikel On undoing, fixing, or removing commits in git von Seth Robertson sehr geholfen, denn darin steht, was zu tun ist, wenn man sich in eine unglückliche (more...)

Book – Hatching Twitter: A True Story of

Book – Hatching Twitter: A True Story of

Book - Hatching Twitter: A true story of...Just finished reading Hatching Twitter: A True Story of Money, Power, Friendship, and Betrayal and I must say that I wasn’t as impressed as when reading for example The Everything Store. The book is more about politics and opportunities than about creating opportunities and value or generating great ideas that others can build on. Of course this can still offer a great story and be a good (more...)

Book – The everything store

Book – The everything store

The everything store

The everything storeThe idea of the everything store was simple: an Internet company that served as the intermediary between customers and manufacturers and sold nearly every type of product, all over the world. It is the story of, one of the most successful companies in the world. And the story of its driven founder Jeff Bezos.

Reading the book I think that there are a few (more...)

Reading list of 2014 so far

Reading list of 2014 so far

In this blog post I’ll share a list of books I read during the first months of 2014. There is more business focus compared to previous years…

The everything store

The everything storeThe everything store is one of the books I liked reading most of my reading list this year. It tells the story of so far; The vision and ways of working of the company and it’s founder (more...)

FitNesse add tags to multiple pages at once

FitNesse add tags to multiple pages at once

FitNesseTaggerSearchWe’re using FitNesse as one of our tools for (acceptance) testing. It can be quite laborious in FitNesse to add tags to multiple pages at once. So one my colleagues – Joost van Wollingen – wrote a nifty tool that can mass tag selected pages.

In order to have FitNesse add tags to multiple pages at once, start the Java program. Select the directory from where you (more...)

Visualisierung von Oracle-Performance Informationen

Als hoffnungsloser Laie in Sachen Visualisierung schaue ich immer wieder voller Erstaunen auf die Beispiele, die Kyle Hailey in seinem Blog unterbringt. Ich muss mal wieder neidvoll anerkennen: es gibt Fälle, in denen sqlplus nicht die optimale Repräsentation von Ergebnissen liefert.


Enkitec’s Oracle AWR Data Mining Tool

eAdamEAdam is a free tool that extracts from an Oracle database a subset of data and metadata with the objective to perform some data mining using a separate staging Oracle database. The data extracted is relevant to Performance Evaluations (PE) and/or to Sizing and Provisioning (SP) projects. Most of the data eAdam extracts is licensed by Oracle under the Diagnostics Pack, and some under the Tuning Pack. Therefore, in (more...)


Enkitec’s Oracle Database 360-degree View


EDB360 is a free tool that executes on an Oracle database and produces a compressed file which includes a large set of small Reports. This set of Reports provides a 360-degree view of an Oracle Database. EDB360 is mostly used for one of the following 3 reasons, listed here in order of frequency of use: 1) Keystone of an Oracle database Health-Check. 2) Kick-off for an Oracle database Performance Evaluation. 3) High-level (more...)

Einfügen von Zeilen aus Excel im SQL Developer

Dass der SQL Developer ein großartiges Tool ist, dem ich womöglich verfallen wäre, wenn ich meine Seele nicht an sqlplus verkauft hätte, habe ich vielleicht gelegentlich schon mal erwähnt. Ein in entsprechender Situation sehr nützliches Detail zeigt Jeff Smith in einem aktuellen Blog-Eintrag: die Möglichkeit, Daten aus Excel per Copy&Paste im SQL Developer in eine Tabelle einzufügen. Das zumindest kann ich mit sqlplus nicht durchführen...

Online product recommendations using Hadoop

Online product recommendations using Hadoop

One of the leading portals on BigData, Dataconomy, had an interview with a colleague of mine on product recommendations systems. These are systems aimed towards personalizing content and recommending the ‘right’ products, in other words products that inspire customers. The article – The Science Behind the Finding the Perfect Product – is a nice read that covers quite some areas.

Stack of Hadoop nodesAt we use Hadoop for batches, and (more...)

SQLTXPLAIN PL/SQL Public APIs to execute XTRACT from 3rd party tools

Many tools offer Public APIs, which expose some functionality to other tools. SQLTXPLAIN contains also some Public APIs. They are provided by package SQLTXADMIN.SQLT$E. I would say the most relevant one is XTRACT_SQL_PUT_FILES_IN_DIR. This blog post is about this Public API and how it can be used by other tools to execute a SQLT XTRACT from PL/SQL instead of SQL*Plus.

Imagine a tool that deals with SQL statements, and with the click of a button it invokes (more...)

PDF über PL/SQL erzeugen

Zur Unterstützung meines unterstützungsbedürftigen Gedächtnisses: Morton Braten zeigt einige Möglichkeiten zur Erzeugung von PDF-Reports über PL/SQL.

Flame Graphs for Oracle

Topic: This post is a hands-on introduction to using on-CPU Flame Graphs for investigating Oracle workloads. This technique is about collecting and analyzing sampled stack trace data to analyze and troubleshoot Oracle processes at the OS level (in particular applied to Linux).

Motivations: The techniques and tools described here can be used for performance investigations to complement wait-event based information gathered from the Oracle engine, such as information available with ASH and sql monitoring. They (more...)


My carpenter has been putting in a new floor in a room in my house, and I noticed that he makes some of his tools as he goes along.

It’s not that he doesn’t have a hammer and a cordless electric screwdriver. But every once in a while, he needs to move, align or support something in a way that his standard tools do not support. So he immediately builds an ad-hoc tool out of (more...)

Recent Updates of OraLatencyMap and PyLatencyMap

Topic: This post introduces the latest changes to OraLatencyMap and PyLatencyMap, two custom tools for collecting and displaying Oracle wait event latency details using heatmaps.

OraLatencyMap is a SQL*Plus tool, with a core written in PL/SQL, aimed at studying Oracle random I/O by displaying the latency drill-down of the wait event 'db file sequential read' using heatmaps. The tool can also be used to collect and display event latency histograms for any other Oracle wait (more...)

Wait Event History Sampling, an Experiment in Oracle Performance Analysis

Topic: This post is about a performance analysis technique based on high frequency sampling of wait event history data in Oracle. Two scripts are provided for performing this type of analysis and two example cases are discussed applied to the study random read latency and read workload characterization.

Context: In the context of performance analysis, for example for a study of I/O response time, I want to analyze the flow of all wait events for (more...)

Daylight Saving Time Change and AWR Data Mining

Topic: this article is about a tip for Oracle 11.2 and higher on how to handle DST change when querying directly the AWR repository. In addition a few comments on Perfsheet4, a tool to extract and plot AWR data in Excel.

Introduction: Statspack and more recently AWR reports, (more...)

Decrypt Oracle and database link passwords

At Derbycon 3.0, László Tóth and Ferenc Spala  gave a a new presentation “What’s common in Oracle and Samsung? They tried to think differently… ” (Video). The main focus of the presentation was the Samsung encryption and a new framework called sandy but there was also a small (more...)