Re: Practical Cursors

On Tue, Sep 25, 2001 at 12:06:48AM -0400, Micah Yoder wrote:
> (sorry to reply to a week-old message.  need to keep up with this list more!)

Ditto, but more so.

> I then wrote a daemon in C to do the work and store the results in RAM.  The
> PHP script connected to the daemon via a socket, and passed a request ID and
> the numbers of the records it wanted.  Sure, it was convoluted, but I
> actually got the speed up to where I was fairly happy with it.
>
> If there's a better solution than that, I'm not aware of it.

A technique I've used with some success is to select the primary keys
from the rows you're interested in, and only have to memorize a list of
integers.  Then for each page, select the rows "WHERE pkey IN (...)".
It's sort of a middle ground as far as tradeoffs go.  You don't have to
store a huge amount of data in RAM or temporary files, but you still
have to do the work up front.

The problem I have with persistent per-session connections is that you
end up having basically the same
(per-transaction-overhead * simultaneous-transactions), and you add
(per-connection-overhead * simultaneous-open-sessions) on top.
There are certainly situations where you can do better one way or the
other.. figuring out how to best tune the per-session case scares me.
--
Christopher Masto

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