One of the things I love about my career (Oracle DataBase Administrator) , is how fragile it is on a day in and day out basis. I can say with certainty that every day I turn on my laptop to start working can be my last day working as a DBA. This is not because…
This is a short blog post on how one can prove that a particular partition of the table or index is accessed by a specific query.
A little while ago I blogged about (and open sourced) an Impala-powered soccer visualization demo, designed to demonstrate just how responsive Impala queries can be. Since not everyone has the time or resources to run the project themselves, we’ve decided to host it ourselves on an EC2 instance.
Like many previous IOUG/OAUG/Quest shows, Pythian will be in Denver next week!
First, the most important advice I can give you is to relax and have FUN!
Building a secure Hadoop cluster requires protecting a number of services which comprise Hadoop infrastructure. If you are using CDH distribution, then Cloudera Manager (CM) is one of the components that needs to be secured. There is a good step by step guide in CM documentation, and it’s easy to follow for one server, but what when you have hundreds of them? There are different approaches to the problem of managing server’s configuration at scale, but I’d like to focus on Ansible which is a neat framework for parallel commands execution and complex rollouts.
This is the second article in a series about internals and performance of concurrent managers. In this post, we’ll take a look at three important settings that affect the performance of the concurrent managers: number of processes, “sleep seconds”, and “cache size”. This article might be a bit on the theoretical side, but it should provide a good understanding of how these settings actually affect the behavior and performance of concurrent managers.
How to resolve unusual situation where Oracle was writing trace files into the user directory instead of the usual oracle diagnostic destinations.
When reviewing the performance of some queries, it is sometimes useful to review the sessions statistics for each execution of the query. I had a situation that required to look at these stats so I could see why one query would run fast and sometimes much slower. I wrote a simple wrapper ksh shell script for the query. It saves the session statistics in a table before and after the execution of the query and then prints out the statistics in a pivot report. This turned out to be very handy to me and therefore I chose to share it with the world :)