Pythian

Part 1: How to Effectively Use a Performance Schema

Performance Schema (PS) has been the subject of many, many recent discussions, presentations, and articles.  After its release in MySQL 5.7, PS has become the main actor for people who want to take the further steps in MySQL monitoring. At the same time, it has become clear that Oracle intends to make PS powerful with…

Pythian at Collaborate 15

Make sure you check out Pythian’s speakers at Collaborate 15. Stop by booth #1118 for a chance meet some of Pythian’s top Oracle experts, talk shop, and ask questions. This many Oracle experts in one place only happens once a year, have a look at our list of presenters, we think you’ll agree. Click here…

Avro MapReduce Jobs in Oozie

Normally when using Avro files as input or output to a MapReduce job, you write a Java main[] method to set up the Job using AvroJob. That documentation page does a good job of explaining where to use AvroMappers, AvroReducers, and the AvroKey and AvroValue (N.B. if you want a file full of a particular…

Do AWR Reports Show the Whole Picture?

AWR report is a great source of aggregated information on top activities happening in our databases. I use data collected in AWR quite often, and obviously the easiest way of getting the data out from the AWR is by running the AWR report. In most cases that’s not an issue, but there are certain scenarios when…

How to recover a subset of an Oracle database

Today’s blog post will discuss how to recover a subset of an Oracle database. Many of you would have come across different recovery scenarios, but I’ll be talking about a very different one that happened to me. The following are the details after receiving a call from a client, and checking the environment myself. i) This…

Online Storage Migration without ASM

I recently blogged about Playing with ASM Online Migration and still soul searching from not having jumped on the ASM band wagon. How can online storage migration be performed before ASM came about? One option is using Logical Volume Manager (LVM) and I will demonstrate: Display Volume Group [root@lax ~]# vgdisplay –verbose vg02 Using volume…

Preventing runaway queries using Resource Governor

Section A (Theory) One of the typical reasons for performance issues is runaway queries executed by end users on a busy production database. This problem is fairly common in OLAP or shared systems (OLTP/OLAP) where business users begin executing complex (and often poorly written) queries, leaving their office for hours, and expecting their data to…

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