Hi all, I've coded what I described here: http://gis.19327.n5.nabble.com/possible-tuning-for-evaluation-of-tags-tp5804... Depending on the options and style I see improvements between 1 % and 15 %. (1% for default style and options --route --preserve-element-order, up to 15% for complex styles like those from Minko or Henning) The more complex the style the more improvement you should see. The cache works like this: - common expressions (e.g. the barrier=* term in my example) in rules are detected when the style is read in, each of them has an int field that identifies a valid cache and the result of the evaluation (true/false) - when a new element is processed, the cache is reset (this just means one int value is incremented) - when a common expression is evaluated for the first time, the normal evaluation happens and the result is cached. - when the same expression is evaluated again the cached value is returned if the cache was not already reset - if an action adds or changes or deletes a tag, the cache is reset again (the more often this happens the less efective is the cache) All this requires more or less no extra heap. One remark regarding rules in <finalize> section: If I got that right, they are all evaluated, no matter what tags the OSM element has. For the "normal" rules we use a filter so that rules which cannot match are not evaluated. If you have time, please check if the branch really is faster and - even more important at this point - produces equal output. Gerd