Adjacency List Tree Using Recursive WITH (Postgres 8.4) instead of Nested Set

Posted by Koobz on Stack Overflow See other posts from Stack Overflow or by Koobz
Published on 2010-01-31T10:53:47Z Indexed on 2010/06/15 4:02 UTC
Read the original article Hit count: 388

Filed under:

django

|

adjacency-list

|

django-treebeard

|

nested-set

I'm looking for a Django tree library and doing my best to avoid Nested Sets (they're a nightmare to maintain).

The cons of the adjacency list model have always been an inability to fetch descendants without resorting to multiple queries. The WITH clause in Postgres seems like a solid solution to this problem.

Has anyone seen any performance reports regarding WITH vs. Nested Set? I assume the Nested set will still be faster but as long as they're in the same complexity class, I could swallow a 2x performance discrepancy.

Django-Treebeard interests me. Does anyone know if they've implemented the WITH clause when running under Postgres?

Has anyone here made the switch away from Nested Sets in light of the WITH clause?

© Stack Overflow or respective owner

Related posts about django

Overriding the save() method of a model that uses django-mptt

as seen on Stack Overflow - Search for 'Stack Overflow'
I've been using django-mptt in my project for a while now, it's fabulous. Recently, I've found a need to override a model's save() method that uses mptt, and I'm getting an error when I try to save a new instance of that model: Exception Type: ValueError at /admin/scrivener/page/add/ Exception Value:… >>> More
Where is meta.local_fields set in django.db.models.base.py ?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm getting the error: Exception Value: (1110, "Column 'about' specified twice") As I was reviewing the Django error page, I noticed that the customizations the model User, seem to be appended to the List twice. This seems to be happening here in django/db/model/base.py in base_save(): values… >>> More
Deploying Django on EC2 using Bitnami Djangostack: WSGI script cannot be loadded

as seen on Stack Overflow - Search for 'Stack Overflow'
I've been struggling to deploy Django application on Amazon EC2 using Bitnami Djangostack for the last couple of days. When I go to http://dewey.io I see the default bitnami page (/opt/bitnami/apache2/htdocs/index.html), however, when I open http://dewey.io/portnoy, I get 'Internal Server Error'… >>> More
Internal Server Error with mod_wsgi [django] on windows xp

as seen on Stack Overflow - Search for 'Stack Overflow'
when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order… >>> More
Internal Server Error with mod_wgsi [django] on windows xp

as seen on Stack Overflow - Search for 'Stack Overflow'
when i run development server it works very well, even an empty project runing in mod_wsgi i have no problem but when i want to put my own project i get an Internal Server Error (500) in my apache conf i put WSGIScriptAlias /codevents C:/django/apache/CODEvents.wsgi <Directory "C:/django/apache"> Order… >>> More

Related posts about adjacency-list

adjacency list creation , out of Memory error

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello , I am trying to create an adjacency list to store a graph.The implementation works fine while storing 100,000 records. However,when I tried to store around 1million records I ran into OutofMemory Error : Exception in thread "main" java.lang.OutOfMemoryError: Java heap space at… >>> More
How do I aggregate results from an Adjacency list using PHP's SPL

as seen on Stack Overflow - Search for 'Stack Overflow'
I've tried using nested sets, and they become very difficult to maintain when dealing with multiple trees and lots of other complications.. I'd like to give PHP's SPL library a stab at this (btw, we are PHP 5.3, MySQL 5.1). Given two datasets: The Groups: +-------+--------+---------------------+---------------+ |… >>> More
Most efficient way of creating tree from adjacency list

as seen on Stack Overflow - Search for 'Stack Overflow'
I have an adjacency list of objects (rows loaded from SQL database with the key and it's parent key) that I need to use to build an unordered tree. It's guaranteed to not have cycles. This is taking wayyy too long (processed only ~3K out of 870K nodes in about 5 minutes). Running on my workstation… >>> More
Move node in adjacency list

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi everyone, I am working on an adjacency list with mySQL and can not (atleast by myself) do the thinking needed to make a decent enough query to be able to move a set of nodes (together with eventual children nodes) around. The table has following columns: id name left right Thanks… >>> More
create graph using adjacency list

as seen on Stack Overflow - Search for 'Stack Overflow'
#include<iostream> using namespace std; class TCSGraph{ public: void addVertex(int vertex); void display(); TCSGraph(){ head = NULL; } ~TCSGraph(); private: struct ListNode { string name; … >>> More