We haven't noticed a any change. We switch ai every 120s . Db is
160GB, growing by 75000 records per day
Do you wonder about the cost of having to explain to executives that they lost 24 hours of business data because the last backup ran at midnight (and we assume it's good...) and the DB got hosed at 23:59 the next day? Especially after they talk to a consultant and learn that AI exists and you weren't using it?
Whether there is application "cost" depends on how you define it. Is it transaction throughput? EDI response time? Latency in your application? Whatever it means to you, run some tests in your non-production environment, duplicating production configuration to the extent that you can, and see if you can meansure the cost of running with AI versus without. Assuming reasonable configuration, I doubt it will be a meaningful difference, if it is even measurable.
Gus Björklund and Tom Bascom ran a performance-tuning workshop at last year's PUG Challenge Americas conference, and covered this topic. The end result, using the ATM benchmark, is that there was no negative performance impact to enabling AI. But as mentioned there is a big potential business impact to not enabling it.
Regarding the OS, why do you think AI would affect its performance?
There is a little performance overhead introduced by the after-image journalling feature. When properly configured, for a database with lots of update activity, I have measured (multiple times) a throughput reduction of about 4 percent. Other people's measurements have been consistent with this.
Other overhead resulting from the use of after-image journalling is:
Yes Rob, good reason to enable AI. I think I will try it out on our Dev. server. My main concern was affect on DB performance and admin maintenance.
Are any notes on that performance-tuning workshop last year accessable?
No, the workshop presentations were not made available.
But this year's PUG Challenge is June 9-12 so you coud pop on in and ask questions http://pugchallenge.org
Like Gus I've done some testing -- basically I have only ever been able to detect a difference under very heavy load. And even then the impact is fairly small.
Implementing after-imaging is very low risk with very high rewards. Not implementing after-imaging is a potential retirement event.