Welcome to Datavail’s Blog, where you can read the latest insights, tips and opinions of our experts on all things data and technology.
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.
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 […]
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.
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 […]
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. […]
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.
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.
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 […]
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 […]
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.
Ora-00054 fix! Learn how to resolve Oracle errors, including this truncate error: ORA-00054: Resource Busy and Acquire With NOWAIT 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.