Query cannot be optimized using index

[janfabry]

The current filterByDistanceFrom can't use an index to speed up the query. Because of the trigonometry functions, every lat-lon pair has to be evaluated to find a possible match.

I think you can help the database by specifying the bounding box too (WHERE (lon > $west_limit AND lon < $east_limit AND lat > $south_limit AND lat < $north_limit) AND ABS([trig stuff here])). A semi-smart database can then use the index to prune out the rows that don't match the first part of the query, and only execute the trig functions for the remaining candidates.

[willdurand]

You're right, thanks for the tip!