[OpenLayers-Users] WFS Performance Issues

[HughBarker]

I'm querying and displaying a WFS service that has (potentially) a huge
amount of data - thousands of points, updated in real-time.

I'm (not surprisingly) having performance issues when trying to display
these points in a layer. I'm interested in any suggestions on how to improve
this.

I prefer to use a WFS over a WMS if possible, primarily because I can only
use a refresh strategy on a vector layer (the refresh strategy is essential
for my application). I'm also displaying the underlying data, and while I
know I can do this on a WMS via GetFeatureInfo, it seems easier in
OpenLayers when using a WFS.

I've had a couple of thoughts, but I've come a bit unstuck when
implementing.

1) Display just the most recent point - the equivalent of this WFS call to
geoserver:

http://server/geoserver/wfs?service=wfs&version=1.1.0&request=GetFeature&typeName=underway:ss2011_v03&propertyName=position&maxFeatures=1&sortBy=utctime+D

Use the refresh strategy on this layer with a single point, and have a WMS
to display the other points.

This seems a bit messy, and besides from what I understand openlayers
doesn't support sortBy.

2) Fetch and render only a subsample of points based on zoom level and
bounding box

This seems like a more reasonable solution to me. Ideally I'd like to find
from experimentation how many points I can render with decent performance on
my target platforms, then select only this number of points from the server
- like using maxFeatures, but with a bit more intelligence.

For example, if I'm zoomed all the way out, I don't want to try and render
10k points, but maybe only every tenth - whereas if I'm zoomed right in I
might want to render all points, or some other proportion. And only fetch
points for features I'm interested in, and that are within the map's current
bounding box.

I know this is a rather broad question, but any insights would be
appreciated.

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