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

"Cimode" <cimode_at_hotmail.com> wrote in message news:1178173985.960152.227740_at_l77g2000hsb.googlegroups.com... [snip]

>> Eliminating self-joins is beneficial regardless of the implementation.
> Beneficial to what ? Performance ? What performance ? Response
> time ? concurrency ? cost of administration ? (Please answer these
> precise questions). Do you realize that despite some lengthy (maybe
> worthy) attempts at clarifying your point, some people here have no
> clue what you are talking about.
>

I'll try to be as concise as possible. Eliminating multiple self-joins reduces the number of passes through the data required to answer a query. This reduces (1) execution time, (2) the duration that locks are held, (3) the amount of I/O required, (4) CPU utilization, and (5) the amount of memory required. The reduction in execution time improves response time. The reduction in the duration that locks are held improves concurrency. The reduction in I/O required, CPU utilization, and memory required improves overall throughput. I would venture a guess that the cost of administration or at least of maintenance would be reduced as well: I personally think it's a lot easier to follow a simple fetch loop followed by a simple UPDATE FROM than a complicated set-based solution with four outer theta-joins, an outer equijoin, an inner equijoin, an aggregation and a union.

[snip] Received on Thu May 03 2007 - 10:12:51 CEST