Re: Microsoft destroys TPC-C records!

> You always use HINT in writing SQL?

Where did I say that I "always use HINT in writing SQL?" I don't always use hints. But as I said, "It's nice to be able to use hints to change the path." It doesn't mean that I always use them. But I'm glad that they are then when I want to.  

> > Because it's very hard for a db to fully understand the applications
> > that are running against and the users who use the db. After all, how is
> > the db to know that I plan on performing a major load this weekend? Or
> > that for the next week, I'll be experiencing a 50% increase in the
> > number of users?
>
> But the db know the data distribution which I think DBAs, developers or users may not exactly know.

The DBAs, and especially the developers should have a good idea of what their data will look like and how it's going to be used. If they don't, how can they take advantage of the many opportunities that Oracle gives them? Besides, this is what they are getting paid for. And the db will never know how I plan on using the data in the future. I currently have a system where we spent 6 months loading data. During that 6 months, my 5 MByte redo logs switched every 30-45 seconds. I was generating tons of redo. A self tuning db may have increase the redo log size automatically. For the last 3 months on that system, we haven't loaded any data. And that system is not currently being used too much. So I may not see a log switch for a day or two. A self tuning database would have probably resized my redo logs to be much smaller so that they'd switch more often. But the db has no idea that I'm planning on loading tons more data in the next few months. Had the db resized the redo logs for me, I would've had problems in the coming months. Thankfully I'm the one in control of the redo log sizes for that system.

As another analogy. My current car hardly requires any maintenance. It only needs a tuneup every 100,000 miles. All I do is change the oil. And the car has a reminder light that tells me when to change the oil based on my driving conditions. (sounding like a self tuning db?). For the average Joe, this car is ok. But I doubt than any race car driver would put up with a car like this. They want to be able to tweak and tune every single piece of their car. For a big, high transaction db, I'd want to have the race car, not the car sitting in my neighbors driveway.

Just my 3.14159 cents worth,
Brian

-- 
========================================
Brian Peasland
Raytheons Systems at
  USGS EROS Data Center
These opinions are my own and do not
necessarily reflect the opinions of my 
company!
========================================