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Welcome to Datavail’s Blog, where you can read the latest insights, tips and opinions of our experts on all things data and technology.

Author: Jeremiah Wilton
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Too Many Flashbacks

With apologies to Dr. Seuss. Did I ever tell you the makers of RAC had seven features and named each flashback? Well they did, and it wasn’t a smart thing to do. You see, when the customers wanted a clue as to how to keep data from getting deleted the RAC folks said “flashback” and customers heeded.

Jeremiah Wilton | January 25, 2012

Finding non-default configuration settings in SQL Server

In our Remote DBA practice, we frequently perform comprehensive system reviews for our customers on their database services. Among the things we always check for are non-default settings for the database software. We want to validate that any non-default setting is set that way for a good reason, and that any setting that is default […]

Jeremiah Wilton | August 25, 2011

Amazon RDS for Oracle: First Impressions

On Tuesday, Amazon announced availability of an Oracle version of their Relational Database Service (RDS). RDS is one of Amazon’s cloud services. You can think of it as “database as a service.” Amazon provides a running database, storage, horsepower and a variety management tasks. And all you have to do is store you data in it. RDS has been available with a MySQL engine for some time, but the Oracle version of this service has been long anticipated.

Jeremiah Wilton | May 26, 2011

Determining optimal Amazon S3 transfer parallelism

Amazon’s Simple Storage Service (S3) is a robust, inexpensive and highly-available internet data storage service.  At Datavail, we occasionally help our customers design and implement S3-based backup strategies. Compared to conventional off site tape vaulting services, the advantages of vaulting database and other backups to S3 are many.  S3 backups are always on line, so […]

Jeremiah Wilton | April 23, 2011

EC2 outage reactions showcase widespread ignorance regarding the cloud

Amazon EC2’s high-profile outage in the US East region has taught us a number of lessons.  For many, the take-away has been a realization that cloud-based systems (like conventionally-hosted systems) can fail.  Of course, we knew that, Amazon knew that, and serious companies who performed serious availability engineering before deploying to the cloud knew that. […]

Jeremiah Wilton | April 22, 2011

Oracle tablespace hot backup mode revisited

Here’s a revised version of an old popular article I wrote over ten years ago. I wrote this when I was at Amazon.com, long before I came to work at remote DBA provider Blue Gecko. Enjoy! Oracle’s pre-RMAN hot backup mode is the subject of one of the most pervasive and persistent misconceptions about Oracle.

Jeremiah Wilton | December 9, 2010

YPDNGG: You Probably Don’t Need Golden Gate

Before launching into this, I must give due deference to Mogens Nørgaard’s landmark article, You Probably Don’t Need RAC (YPDNR), available here, but originally published Q3 2003 in IOUG Select Journal. Mogens showed that you can be a friend of Oracle without always agreeing with everything they do.

Jeremiah Wilton | November 22, 2010

Good OCP / bad OCP

For those contemplating launching a career in Oracle database administration, there are essentially three routes: Oracle education and certification (OCP) Third-party educational programs (University and private training) Self-directed study and experimentation Most entering into the field assume that to be employable, they must become an Oracle Certified Professional (OCP).  They might be surprised to know […]

Jeremiah Wilton | August 4, 2010

How Incompetence Stimulates the Information Technology Economy

As information technology professionals, we constantly complain about mismanaged projects in which we have the misfortune to be involved.  Frequently, someone with more power than knowledge – usually in management and under the sway of a persuasive vendor sales team – has come up with a systems design most politely described as novel. Because of […]

Jeremiah Wilton | April 8, 2010

Converting Hexadecimal Oracle SCNs to Decimal

Oracle serializes transactions and manages concurrency and recovery using an ever-increasing number called a system change number, or SCN. Usually, we see these numbers expressed in decimal, in places like the v$ views and the alert log. Occasionally, however, Oracle’s code expresses SCNs in hexadecimal. Unfortunately, you can’t just perform a straght conversion from hex to dec to express these hex SCNs in dec.

Jeremiah Wilton | November 19, 2009

ORA-00054: Resource Busy and Acquire With NOWAIT Specified

Ora-00054 fix! Learn how to resolve Oracle errors, including this truncate error: ORA-00054: Resource Busy and Acquire With NOWAIT Specified.

Jeremiah Wilton | September 22, 2009

ORA-12154: TNS:could not resolve the connect identifier specified

When a program needs to connect to an Oracle service via Oracle Networking (SQL*Net), it must look up the connect data for that service somewhere. When the lookup fails, the Oracle client code raises ORA-12154. Most people will encounter this error when their application tries to connect to an Oracle database service, but it can also be raised by one database instance trying to connect to another database service via a database link.

Jeremiah Wilton | March 4, 2009

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