Re: Cost vs efficiency?

From: <sweidanz_at_yahoo.com>
Date: Mon, 15 Oct 2001 19:33:52 +1000
Message-ID: <rbJy7.6$mL2.511@nsw.nnrp.telstra.net>

Tom,
Thanks for taking the time to answer my question. Can i just clarify few things:
1. The name of the book you are referring to, is that Practical Oracle8i-Building Efficient Databases or there is a new one?

2. I haven't got what you mean totally different queries? My understanding is that the two queries are the same, in terms of tables, logic, criteria and everything else except that they are written in two different ways. The result is going always be the same, right. So i am assuming that i have one query and i want to figure out which of the two ways is more efficient. I will rely on the cost to find out the best. Otherwise, how by looking at the query, execution plan, i would tell which one is more efficient?

Like for example, sometimes i got asked by developers, which way of writing this query is more efficeint, this way or that way? My answer would be run the execution plan for both and see which one has the least cost and use it. After reading your comments i am confused and i might be wrong with my understanding. Is there other ways to find out?

I am planning to buy the book you and Sybrand recommended, but if you can give me some lights now, i would really appreciate it.

Thanks,ZS Received on Mon Oct 15 2001 - 04:33:52 CDT