Index bouncy scan

There’s a thread running on OTN at present about deleting huge volumes of duplicated data from a table (to reduce it from 1.1 billion to about 22 million rows). The thread isn’t what I’m going to talk about, though, other than quoting some numbers from it to explain what this post is about.

An overview of the requirement suggests that a file of about 2.2 million rows is loaded into the table every (more...)

APEX Survey Results: Addressing Performance

Yep, I'm still doing this. A bunch of questions to come, many worth the visit. Just a few weeks between drinks, so to speak. My annual review is a little late, too. Anyway...

Time for the performance questions in my 2015 survey. A favourite topic of mine, and my boss, Penny Cookson, lives for tuning.

Q9. How do you proactively address performance? (tick all that apply)

Tune SQL - I would be surprised if this (more...)

Skip LOV Validation for ADF BC Bulk Insert

This post is about ADF BC LOV. I will describe how you could optimize bulk insert of new rows into VO, when some of the attributes are assigned with LOVs. By default ADF would validate new row attribute value through LOV (LOV Validation and Programmatic Row Insert Performance) for each new row. This will lead to bad performance, especially if you insert a set of new rows programmatically - there will be multiple (more...)

Oracle SOA Suite 12c tips – Tuning the SOA infrastructure thread pool

One of the new capabilities of Oracle SOA Suite 12c is the ability to control the SOA infrastructure thread pools, except the resource pools for EDN and the adapters, with Oracle WebLogic Server work managers. Each partition will has its own work managers defined. This allows you to separate services in partitions and, to some extent, tune them separately based on for example specific SLA requirements.

Well, this blog posting is not about explaining the (more...)

Troubleshoot: perdiendo el control

Me encontraba sumergido en un proyecto de diseño e implementación de un Oracle RAC 11gR2, en las instalaciones de uno de mis clientes regulares, cuando fui interrumpido por el jefe del proyecto. Me empezó a comentar sobre sobre un problema de desempeño que venían experimentando con la base de datos principal, que aún se encontraba en Oracle RAC 10gR2, y que como parte del proyecto sería actualizada a 11gR2. Habían ya identificado que (more...)

Troubleshoot: optimizador confundido

Unos días atrás me reportaron un problema de mal desempeño de una aplicación bancaria. Resulta que si bien el número de transacciones no era alto, el valor monetario si lo era, por lo que era prioritario que se completase casi instantáneamente. Con el pasar del tiempo estas transacciones iban demorando más y más, al punto de que eventualmente alguna de ellas era dada por fallida y debía ser reiniciada, poniendo nerviosos a todos los involucrados (more...)

Book Review – High Performance MySQL 3rd Edition

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This is THE MySQL performance book. Period!

Every chapter is very well crafted, with a precise balance between theory and practice, and full of invaluable nuggets, sometimes transcending the MySQL arena and applicable to any database! Such cases are Chapter 2-Benchmarking MySQL and Chapter 3-Profiling Server Performance, very solid foundations for the reading ahead.

All over the text, authors propose tools, examples of use and proven diagnostic techniques, that will greatly improve your performance firefighter skills and enhance your knowledge of MySQL internals. Nevertheless, what I liked the most from this book is taking into (more...)

Las paradojas del tiempo

En esta ocasión les voy a contar sobre un problema muy singular y la forma en que fue resuelto, estoy seguro que muchos usuarios de AIX 6.1, y quizás de otras plataformas, deben tener este problema y no lo han notado aún.

La historia se remonta a unos meses atrás, había concluido el upgrade de una base de datos desde Oracle hacia Oracle, (more...)

Performance Enlightening – Craig Effect (Tropa de Elite)

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During the past week I had the opportunity to assist both the Oracle Performance Firefighting and the 
Advanced Oracle Performance Analysis and only can say: awesome!!!
Craig Shallahamer is a great teacher and has a lot of resources to effectively share knowledge, even if 
the subject is complex like buffer cache structures or arid like the mathematical foundation required for 
perf analysis. That is not all, he provides valuable tips of the trade or anecdote nuggets, dipped on a 
very fresh and sometimes humorist perspective.
The result: we started searching for those  (more...)

SQL Monitor details for later tuning.

Tuning has always being good fun and something like a challenge for me.

From time to time we are being asked to find out why something did run slow while you are sleeping; answering this question is, in most cases, a challenge.

The problem:

My batch did run slow last night, can you let us know why? Or why did this query run slow? Are questions we, as DBAs, have to answer from time to (more...)

I Can Help You Trace It

The first product I ever created after leaving Oracle Corporation in 1999 was a 3-day course about optimizing Oracle performance. The experiences of teaching this course from 2000 through 2003 (heavily revising the material each time I taught it) added up to the knowledge that Jeff Holt and I needed (more...)

Catching up…presenting and taking part in Challenges

| Jun 14, 2010

I regret not being able to write new things more often, but in fact it only means I am OK: very busy with work, doing private stuff (which is important since life is not all about working), enjoying the three young kids and trying to achieve some good results in track and field. And for that last goal, I can say I did. After a few months of struggling to find a tiny piece of shape comparable to last years shape, just in time I found it. I won the gold medal in the Dutch Championships 400 metres hurdles. OK, be (more...)

El query dinámico de los pobres

Luego de casi dos semanas sin postear, les presento un caso curioso que me ocurrió en estos días. Pues ocurre que como parte de una tarea de afinamiento de aplicaciones que me solicitó un cliente, encontré con ayuda de dbms_monitor y tkprof, que la sentencia responsable del problema de desempeño era una muy peculiar, se trataba de un query que siendo estático estaba escrito de tal forma que pretendía satisfacer varios criterios de búsqueda, (more...)

¿Query dinámico?, pero sin perder de vista el contexto

Es relativamente frecuente que tengamos que recurrir a SQL dinámico cuando no sabemos en tiempo de compilación el texto completo de la sentencia. Si bien en los tiempos de Oracle 7 la única forma de lograrlo era usando dbms_sql, en la actualidad la forma preferida de procesar SQL dinámico es con execute immediate, el problema radica en que no se hace buen uso de él y se termina generando código no reutilizable y (more...)

Available January

I've just discovered that my current contract, with a healthcare company in Hampshire, will not be extended beyond the end of the year. So, in the current economic climate, I've decided to start a blog in order to drum up more business.

My primary skills are in troubleshooting and tuning Oracle systems, from entire databases to individual SQL queries.

If you have an application running on an Oracle database and you need someone to investigate an issue on that system, get in touch.

"My name is Peter Moore. I am a professionally qualified and highly experienced database administrator with extensive (more...)