[postgis-users] VMWare and PostGIS

Stephen V. Mather svm at clevelandmetroparks.com
Mon Jan 14 08:16:41 PST 2013


Thanks Brian,

> * What kind of queries on what kind of data?  If you are servicing thousands of visitors
> and answering the same dozen questions again and again, like at a kiosk, how far is this
> thing from me and how far is that... what about pre-processing all the answers in a batch
> and then not invoking geometry at GUI time at all ?  non-spatial is generally a lot faster
> than spatial !

Ah, more details is always better.

The number of users now is in the dozens, but expect it to be in the hundreds simultaneous in the next few months.

As to dynamic vs pre-built, the bottlenecks are with pgRouting, so arbitrary and random queries.

If the routing traverses just a few short miles (< 5) the queries return pretty quickly, acceptably so for a web application.  Once they traverse a larger network, CPU is a bottleneck (currently) but at current IO speeds, we're not far from a disk bottleneck.  In other words, once we throw faster processors at it (and more of them) we'll hit the limits of the current disk setup, hence the question.

That said, subsequent similar queries traversing similar networks are very fast, so it seems like there is some caching opportunity, but I have not grokked how to leverage that.

> Short point - PostGIS needs some kind of multi-core strategy, that it does not have now.

Agreed.  Has anyone floated a proposal for this?

Best,
Steve


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