Oracle Far Sync is an Oracle 12c new feature for Oracle Data Guard. This feature is meant to resolve the performance problems induced by network latency when you maintain a standby database geographically distant of the primary database. In this type of situation you sometimes have to make a compromise between performance and data loss. [...]
Back in March of last year I wrote an article on the five frequently misused metrics in Oracle: These Aren’t the Metrics You’re Looking For.
To sum up, my five picks for the most misused metrics were:
- db file scattered read – Scattered reads aren’t always full table scans, and they’re certainly not always bad.
- Parse to Execute Ratio – This is not a metric that shows how often you’re hard parsing, no matter how (more...)
Originally posted by me on the Pythian blog. This is an older post that I somehow forgot to post on my own blog, but another recent redundancy foul-up reminded me of it.
The story you are about to read is based on actual events. Names and paths have been changed to protect the innocent. I call this scenario “The Perfect Storm” because it took just the right combination of events and configurations. Sadly, this doesn’t (more...)
WordPress 3.8.3 came out yesterday. It’s a small maintenance release, with the downloads and changelog in the usual places. For many people, this update will happen automatically and they’ll just receive and email to say it has been applied.
I’m still not sure what to make of the auto-update feature of WordPress. Part of me likes it and part of me is a bit irritated by it. For the lazy folks out there, (more...)
Confio software is hosting a live discussion on twitter tomorrow Tuesday April 15 at 12pm PST on the subject of Oracle performance.
I’ll be online answering performance questions and have invited many other friends to participate. Some friends who’ve said they’ll be there are
Participation and tracking of the discussion can accomplished by either posting with and following along with the #datachat hashtag.
I was working on a script for the ultimate RMAN backup validation and hoping to submit the article for an Oracle conference.
To my chagrin, one version of the script was failing for one condition and the other version would failed for another condition.
Basically, the script was very buggy.
The objective is to create a RMAN script to validate 8 backupset at a time.
I decided to use Bulk Collect and Limit clause.
My Exadata IORM session went well. Lots of follow back discussion plus questions are still pouring in. I promise I will answer them as soon as I return to Australia after couple (more...)
I found this hilarious
SQL> startup ORACLE instance started. Total System Global Area 1469792256 bytes Fixed Size 2402776 bytes Variable Size 536872488 bytes Database Buffers 922746880 bytes Redo Buffers 7770112 bytes Database mounted. ORA-19821: an intentionally corrupt log file was found
Really ? I intentionally corrupted my log file ? I dont think so !
Another big public username and password leak…
Some good reading on how it was done, and thus ensuring your code isn’t prone to SQL injection here:
Once you get into pluggable database territory, you might need to check your usage of "alter system enable restricted session", because unless you’ve patched, there’s a little bug which lets you enable restricted session, but wont let you get out of it ! :-)
SQL> alter session set container = pdb12; Session altered. SQL> alter system enable restricted session; System altered. SQL> select logins from v$instance; LOGINS ---------- RESTRICTED SQL> alter system disable restricted (more...)
I had the pleasure of being a guest of the Norwegian User Group for the second year in a row on their famous cruise conference at the start of April. For a relatively ‘small’ conference (around 300-400 people), the array of quality speakers the group manage to get is always astounding. Martin Nash, Cary Millsap, Tim Hall, Bryn Llewellyn, Martin Bach, Jeff Smith, Doug Burns to name just a few. I gave a (more...)
create table dbaperf.has_data ( column_one varchar2(10) not null, column_two number(10) not null);
insert into dbaperf.has_data(column_one, column_two) values('First row',13 (more...)
I was not aware that I would not be allowed to use my laptop; so I couldn't show all the demos I so carefully prepared. Please download the scripts and execute them yourself.
As promised, here are the materials I used in the session
Maximum manageable storage per VM by ESX version
- 4.1: 32TB (vmdk) / 120TB (RDM)
- 5.0: 60TB (vmdk) / 3.75PB (RDM)
- 5.1: 60TB (vmdk) / 3.75PB (RDM)
- 5.5: 3.63PB (vmdk) / 3.75PB (RDM)
Note that the 60TB limit for 5.0 and 5.1 requires Update 1. Without this the limit is 24TB.
I am sick of this advertisement on my site.
Therefor I am about to move most of my posts to
Thanks for following my blog for so long.