I am back

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It's been a very long time not coming here, about 2 years and half ... and I missed it big time.

Now I moved to Oracle Systems (formerly Sun Microsystems) on a role support-programmer mixed, within RPE (Revenue Product Engineering) on the Extra Care team, with focus on Solaris, Engineered Systems with Solaris, ZFS Storage Appliance and Ops Center. I'm very happy since my job is closer to development, something was (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...)

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...)

Book Review – iOS 5 Programming Cookbook

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You will write iOS apps in less than you think





Being a C/BASIC hardcore programmer for mobile devices in a past life, I enjoyed very much this book because it really helped me grasp quickly many basic and intermediate topics on iOS 5 Objective-C programming, would say after reading the full book I have all needed to program good basic applications; and even after getting practice and experience, guess I will eventually resort on this book as reference. In my opinion this book is awesome and a must for beginners and intermediates.


Honestly, I consider (more...)

Who is using your Undo space? – Improved Script

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Hi folks!
I have extended the Undo usage scripts to include two additional indicators:
1) undo change vector size statistics
2) Used undo records/blocks

and support for RAC infrastructure, so you can spot the hungriest UNDO eaters for any given instance.

Then the script for Oracle 11g is as follows:
set pagesize 400
set linesize 140
col name for a25
col program for a50
col username for a12
col osuser for a12
SELECT a.inst_id, a.sid, c.username, c.osuser, c.program, b.name,
a.value, d.used_urec, d.used_ublk
FROM gv$sesstat a, v$statname  (more...)

First pervasive-post

Today I'm writing this post from a Samsung Galaxy, my hand sized tablet, camera included, microphone and lots of fun.

I have been busy this year and that is thanks to the tremendous success of the Database Machine/Exadata.

Traveled all over the caribbean and south america, plus my first OOW experience as Oracle employee: always exciting!



Bandeja Paisa / Paisa "tray" - Medellin, Colombia


Sao Paulo Subway System

Oracle Open World 2011

The Oracle Exadata: latest Business Weapon

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Sorry I’ve been having a lot of work installing, maintaining and migrating to Database Machines all over Latinamerica for the latest 10 months; that means lot of travels abroad, all of them very exciting, but the real excitement comes from my job working with this wonderful Machine.

Was on the last project when realized how important is this investment for our customers, having this big caribbean Telco installed their first Exadata and later migrated their databases meant for them dramatic performance improvements and the ability to get more up-to-date analytical information and compete (more...)

My Steps to Implement Exadata EHCC

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Last time I was engaged with an Exadata migration, customer asked me about EHCC and how to implement it for their datamarts.

My approach (at that time) consisted on the following:
1) Get a sample of very big objects to play with
2) Used DBMS_COMPRESSION in order to get estimations for compression rates
3) Try every compression type: Basic, Query Low, Query High, Archive Low, Archive High and recorded size reductions, time to import and time for FTS.
4) Recorded and compared timings for various batch processes and (more...)

From 3Tb to 1.5Tb Using standard COMPRESS and PCTFREE

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I've been working on a migration project, with very aggressive dates and a couple of requirements that increase difficulty: switch from filesystem to ASM, using 50% of new storage... yes, you got the right picture, we don't have full set of disks for ASM to fit all data, therefore I need to move data trying to release complete datafiles in order to free those logical volumes or LUNs, and later add them to ASM.

Anyway, I realized that given this is a DSS or Datawarehouse, there is some margin to increase "data density" per block, (more...)

Migration time: Oracle Database Machine/Exadata

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Guess what I've been doing lately??!! taking vacations? well, that was on September (and that's another post) watching movies? wish I could... none of that, but something more exciting: migrating multi-terabyte datamarts to some Oracle DBMs/Exadatas!!!

My first attempt back in March was Datapump, and it worked fine up-to database sizes around 2Tb using import over the network (DB Link) which is cool, but has the following caveat: cannot disable estimation when using DB Link and therefore much time is spent just measuring how much info Datapump is going to transfer.

However, lately I've been (more...)

Oracle patchset 11.2.0.2 released (and docs updated)

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***Sep 13th, Patchset has been released***

Today Oracle released latest patchset for Database Server 11g2: 11.2.0.2 which packs some very interesting improvements and new features; for now, release covers Linux x86 and x86_64, with download measuring near 5Gb(!) .

Also updated all documents for release 11.2, in order to reflect improvements introduced by 11.2.0.2. You can see on following picture a New Features addition
From now on you will see full distribution instead of a patchset (MyOracle Support Note 1189783.1 ), that's why seven ZIP (more...)

Oracle database recovery with data unloading

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What I'm going to share with you is an example of how you can recover from an apparently dead-end situation when a database crashes due to storage failure and gets corrupted.

During past two days I was engaged with a customer where the disk array had a double failure on a RAID-5 arrangement, hence lossing information. When asking for backup... none!!!; unfortunately this database wasn't backed-up regularly (was managed by an application team, not customer's formal Storage-OS-DB areas), database was in NOARCHIVE mode and on top of that NOLOGGING for all objects, including objects (more...)

Back home and writing


After a few trips abroad and very interesting projects with vip-big customers & new features that demanded lot of time and concentration ... I'm back!

Want to share with you some goodies from my trips ... and advice.

Trinidad & Tobago: be aware of displicent and slow service, lot of chinese places.

Brazil, Rio de Janeiro: try Feijoada at Rondinella Rest. (Av. Atlantica, Copacabana Beach); if you go alone, ask for 1 person sizing ... you won't regret!!


Update under the hood … and some extreme side effects

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At first glance, this topic may look trivial, but may be the source for severe performance issues, unnecessary maintenance tasks and/or storage waste.

Yes, you can say "update is so basic, why I should care about it?!", well it may be some cases when using update without care, things may get ugly. I found it playing with my old friend ALTER SYSTEM DUMP BLOCK and a few inserts and updates, over a table with a few columns, two of them VARCHAR2 type.

This was done on an Oracle 10.2.0.4 release database, (more...)

Starting Oracle Coherence 3.5 book review

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Past Friday, Packt Publishing gave me a copy of his newest "Oracle Coherence 3.5" book, which you can find clicking the book cover image below.



Coherence is a Middleware product from Oracle which main purpose is being a high performance Cache on the 2nd tier, thus improving performance reducing unnecessary traffic or requests to the database server. On next weeks my comments on this book...




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Oracle Exadata/Database Machine… nice to meet you

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During the last four or five weeks I've had the rare privilege of working with this amazing piece of engineering, the Oracle Database Machine.

Engaged during deployment of it, I've faced the setup steps on the SW side, applied upgrade patches & side-to-side with Oracle Sun engineers bringing this marvel to life... it's just exciting, watching all the slightly-bluish-green leds showing HD activity or admiring the most precise cabling I've ever seen... there is just one word: precision. I remember my first experience with an HP XP12000 SAN, five years ago, being not that exciting (more...)

Oracle 11g Streams Implementer’s Guide – Highlights – Part I

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I finished reading this very nice book on Oracle Streams... yes, the one I shared you weeks ago (See post My first assignment on book reviews). Now as promised, getting back to you and share my comments on the book, starting with those chapters that clearly make the difference against other Oracle Streams books on the market, those which are more like "rephrasing" the manual.

Chapter 2 and Chapter 3 provide the foundation for success on implementing Streams, this is the Analysis and Design phase that is often overlooked ... but pays high rewards to (more...)

My first assignment on book reviews

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During the past week, Packt Publishing gave me a copy of his newest "Oracle 11g Streams Implementer's Guide" book, which you can find clicking the book cover image below.

There you may even get a free sample chapter (Ch 5 on N-Way Replication), for free!!!.

So, on days to come you may see here postings related to this endeavor... stay tuned!

See comments on the book, follow link to post Oracle 11g Streams Implementer's Guide - Highlights - Part I

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How to innocently corrupt a data table block

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This really happened to me when trying to learn how the INITRANS
attribute works, was very surprising how easily you can have this
transitory error state.

Replicate the error is very straightforward, you just need one table and
4 transactions. It happened on a 10.2.0.4 database.


CREATE TABLESPACE UNIF
DATAFILE '/u01/MASTER/unif.dbf'
SIZE 20M
EXTENT MANAGEMENT LOCAL UNIFORM SIZE 64K
SEGMENT SPACE MANAGEMENT AUTO;

create table scott.t2 (c1 number, c2 char(10)) tablespace unif;

Table is created with storage defaults, therefore INITRANS is 2 initially.

insert into scott.t2 (c1, c2) values (more...)

Latest storage Adventure

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Datamarts/Datawarehouse performance issues can be scaring events, taking into account the massive amount of data they handle; the tuning task is even more daunting if they're used for operational day-to-day decision making.

During the last week and days, I've been involved on a 15 Tb datamart with performance issues on dataloading, not querying. Tablespaces for indexes and data share filesystems, nowadays this is not a concern anymore, however I prefer to encourage customers to allocate independent storage for each type, that way they are able to discriminate the source of IO.

They have concurrent schedules (more...)