getFeatureInfo slow with large map files

[Arnulf Christl]

Hi,
just checking if anybody experienced the same problem:

A very large map file with > 100 layers and > 100 classes per layer 
works fine when requesting maps.

But getFetureInfo-requests on one single layer always take 10 seconds or 
more to get answered. First we suspected poor tuning in PostGIS (join 
over three tables) but no - even with a flat table its the same thing.

To confirm this behaviour we extracted this queryable layer and put it 
into a separate WMS, performance is immediately fine. So we have a 
workaround but Nonetheless we wonder what causes this behaviour and 
where else it might steal us a second or two.

Best,