[Tile-serving] Osm2pgsql table partitioning

[Sven Geggus]

Kai Krueger <kakrueger at gmail.com> wrote:

> What would be the most useful partitionings to test this on? What would 
> likely show the biggest speed improvements with the default style sheet?

Talking about polygons this is almost certainly a partition between
buildings and all the rest.

The database queries making low-zoom rendring slow especially on traditional
disks are forests because of the many seeks skipping building polygons in
the area.

> One possibility would be to partition the polygon table into "buillding 
> is null" and "building is not null". That would split the tables roughly 
> 6:1, and many of the slower queries in the default stylesheet already 
> have a "where building is null" clause.

I would go for this.

Sven


-- 
"The only thing we have to fear is fear itself" (Franklin D. Roosevelt)


/me is giggls at ircnet, http://sven.gegg.us/ on the Web