Digital Economy and Society Index (DESI) 2015
The data presented by Digital Evolution Index seems supported by data from the European Commission. The EU defined a Digital Economy and Society Index to support and measure progress on the digital agenda for Europe:
The Digital Economy and Society Index (DESI) is a composite index that summarises relevant indicators on Europe’s digital performance and tracks the evolution of EU member states in digital competitiveness.
The Digital (more...)
Theory of constraints
Think it was back in 1993 I first read The Goal by Eliyahu Moshe Goldratt. The book was one of the first and most notable in the genre of business novels. The book – The Goal – introduces the theory of constraints (TOC) process for improving organisations. The book is set in a manufacturing company. However the book provides the context for a more generic approach to continuous improvement.
Theory of constraints
A client of mine was busy correcting one of his development streets and therefore the NLS charactersets of about 10 220.127.116.11 EE databases had to be changed.
Most of the databases were originally configured with WE8ISO8859P15, others with WE8ISO8859P1 and all of them had to get WE8MSWIN1252. Some of them were single instances (export, development and test), some RAC (acceptance) and some of them were RAC plus Dataguard (production, for the procedure (more...)
Design for outcome-oriented teams
While developing an organisation structure for an Agile or Lean business, there is a strong focus on teams being responsible for business outcomes (outcome-oriented teams). These teams are opposed by so called activity-oriented teams (teams responsible for an activity).
To understand the why of the focus on outcome-oriented teams, we need to understand what is a business outcome. Selling a product and generating revenue is an example of a business outcome. (more...)
Sometimes you do what you have to do. So here I confess doing something I usually avoid: forcing an Execution Plan (which is not the same as using a more conventional method for Plan stability).
This is a case on 18.104.22.168.0 base release where the application vendor sets the optimizer to 9i, and tweaks other CBO parameters in questionable ways, then some queries produce suboptimal plans (as expected); and you are (more...)
You’ve finished the design for an Apex application, and the manager asks you “when will you have it ready to test”. You resist the temptation to respond snarkily “how long is a piece of string” – which, by the way, is often the only appropriate answer if they ask for an estimate before the design work has started.
Since you have a design and a clear idea of what exactly this application will do, you can build a reasonable (more...)
- Fact 1: Dazzling animated displays (sprites, shaders, parallax, 3D) are more plentiful and easier to make than ever before.
- Fact 2: More natural and expressive forms of input (swiping, pinching, gesturing, talking) are being implemented and enhanced every day.
- Fact 3: Put these two together and the possible new forms of human computer interaction are endless. The only limit is our imagination.
That’s the problem: our imagination. We can’t build new (more...)
event histogram metric, a script and some related comments on collecting and displaying wait event latency histograms for Oracle performance troubleshooting.Why:
Latency histograms (and by extension wait event histograms) provide very useful information when troubleshooting performanc
e for systems exhibiting response time with multi-mode distribution. In such cases average wait values are often not sufficient to understand the behavior of the system under study and histograms
provide a finer level of details. A (more...)
In most cases edb360 takes less than 1hr to execute. But I often hear of cases where it takes a lot longer than that. In a corner case it was taking several days and it had to be killed.
So the question is WHY edb360 takes that long?
Well, edb360 executes thousands of SQL statements sequentially (intentionally). Many of these queries read data from AWR and in particular from ASH. So, lets say your ASH (more...)
Topic: PyLatencyMap v1.2
and how it can be used to produce heat map visualization of SystemTap histograms.Introduction:
When studying storage performance, the latency drill down is a very important data source. Measuring the average I/O latency is often not enough, latency histograms are proven to more suitable for investigating modern storage systems. This is because for many storage systems the response time has multiple modes: think for example of the common case of storage (more...)
During my 17 years at Oracle, I developed several tools and scripts. The largest and more widely used is SQLTXPLAIN. It is available through My Oracle Support (MOS) under document_id 215187.1.
SQLTXPLAIN, also know as SQLT, is a tool for SQL diagnostics, including Performance and Wrong Results. I am the original developer and author, but since very early stages of its development, this tool encapsulates the expertise of many bright engineers, DBAs, developers and (more...)
Contentcuratie met expertlijsten
Met ruim 9 miljoen producten in de winkel valt er natuurlijk van alles te ontdekken in een winkel als bol.com. Om je te inspireren en wegwijs te maken in dit enorme aantal, worden er steeds meer experts en productkenners uitgenodigd om expertlijsten te maken.
Naast productspecialisten in dienst van bol.com krijgen verkopers, leveranciers en affiliate partners de mogelijkheid om selecties te maken en zo bezoekers van bol.com te inspireren (more...)
Working with database performance troubleshooting means dealing with challenging and exciting problems. But it also means doing certain things over and over. And over. Like typing the same query or clicking the same button zillion times a day. And when you’re doing something very frequently, anything that can be done to simplify or automate such tasks becomes very important. So I decided to share some of the tricks I use to optimize my working experience in (more...)
Occasionally one might want to know what a segment is made of in terms of block types. For example, you notice that the number of blocks in an index segment is somewhat larger than the number of branch and leaf blocks, and wonder what kind of blocks accounts for the difference. The only way to do this is by dumping index blocks (e.g. as described in Richard Foote’s blog here). Dumping blocks is easy, but (more...)
Meetup maart – Docker en Elasticsearch
Voor maart hebben we twee interessante bijeenkomsten gepland bij bol.com.
Docker Meetup – Deep dive into Docker storage drivers
Op 5 maart hosten we voor de tweede keer een Docker Meetup in Utrecht. De presentaties worden verzorgd door:
- Jérôme Petazzoni (Senior Engineer Docker)
- Kay Davenport (Developer Evangelist ClusterHQ)
Inschrijven kan hier.
GOTO Night: Elasticsearch
Op 25 maart hosten we voor een GOTO night over Elasticsearch. Sprekers zijn:
This post is about the latest updates to PerfSheet4
v3.7 (February 2015). PerfSheet4 is a tool aimed at DBAs and Oracle performance analysts. It provides a simplified interface to extract and visualize AWR
time series data using Excel pivot charts.
PerfSheet4 is aimed at querying and displaying time-series data from AWR repository tables. This is very a rich source of information to analyze database workloads and trends in the context of performance analysis or (more...)
This post is about tracing logical and physical reads in Oracle using systemtap. You will find a few examples illustrating the main mechanisms used by Oracle to do physical and logical I/O and you will learn how to build systemtap scripts to further explore and troubleshoot Oracle I/O.Introduction:
Performing input/output to and from the storage media, i.e. physical I/O, is one of the critical tasks underlying all database engines. When accessing data (more...)
This post is about using SystemTap
for investigating and troubleshooting Oracle RDBMS. In particular you will learn how to probe Oracle
processes and their userspace
functions. These techniques aim to be useful
as well as fun
to learn for those keen into peeking under the hood
of the technology and improve
their effectiveness in troubleshooting and performance
is a very powerful technique that can be used to complement the available (more...)
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...)