Re: A new proof of the superiority of set oriented approaches: numerical/time serie linear interpolation

On 29 avr, 16:21, "Brian Selzer" <b..._at_selzer-software.com> wrote:
> I would have done it differently. I would have used a cursor to generate
[Snipped]
I respectfully think you miss the point of the entire thread. Thinking procedurally (use of cursors) is inherently inferior to set oriented approaches independently of a specific implementation and regardless of how one defines performance as response time, ability to run well in concurrent query environment and so forth.

> I would bet the process would run much faster than your solution. In rare
> cases, cursors can actually increase performance.
I don't think one can establish that for a certainty. If you ask me I tend to think that even in direct image systems, set oriented are superior because they give less time outs in highly concurrent environment. I had the opportunity to take away several hundred cursors based processes that would run faster on development environments but would totally time out in heavy load environment. I have not encoutered so far any cursor based solution that was not imposed by a poor design. And I have not found any satifying cursor based solution. Often the use of cursor and (procedural) dictates unacceptable tarde off where evrything is given up for reponse time sake...

One should keep in mind that response time is only one of several criterias that may define performance. Defining performance only according to response time is simply a consequence of using poorly designed direct image systems.
[Snipped implementation specific diret image internals]

> I generally don't advocate the use of cursors, but sometimes the optimizer
> just isn't smart enough to generate what I know to be a minimum plan, so in
> those cases I use them.
Speaking of optimizers in the case of direct image systems is like asking a cow to run a race. Only a TRDBMS that would correctly separate logicala and physical could inherentlyy allow optimization.

Regards... Received on Sun Apr 29 2007 - 18:13:06 CEST