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From "JupiterHost.Net" <>
Subject Re: Database transaction across multiple web requests
Date Fri, 31 Mar 2006 15:34:28 GMT

Tomas Zerolo wrote:
> Howdy,

Howdy to you :)

> this is not strictly a modperl question, but I'm sure some of you are
> downright experts on this.
> We have a modperl2 applicattion with a database backend (PostgreSQL,
> DBI). For session management we use Apache::Session.
> Now the need has arisen to serve requests yielding many records as
> answers -- so the user wants to page through them, a bunch at a time,
> search-engine style.

use Data::Paginate;

As far as the queries go you have basically two choices:

a) If the connection is persistent and you can pass a hash around then 
do the query once, store the data in the hash keyed on the session.

The problem here is your memory (and possible security) issues would 
seem to overwhelm the "one query" only benefits. (plus your initial 
query page would have one huge result set to manage so itd take alonger)

b) Is to do it like the Example in Data::Paginate's POD:

  Initially you do one simple count query. That is used to build your 
pagination object and then each request does a LIMITed SELECT on the 
current pages's records.

Its quite fast and efficient and easy to code and maintain, we use it 
all the time (essencially pasting in the example code). *And* if your DB 
connection is persistent its even zippier :)


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