On Tue, Jan 10, 2012 at 5:02 PM, Marco Hugentobler <[email protected]> wrote: > Hi Martin > > >>- it may be interesting to measure the proportion of time necessary >>for field calculation / searching. I believe the the evaluation takes >>just a small amount of time compared to time required for fetching of >>features, therefore a fast engine might not necessarily speed things >>up significantly > > That would be very interesting (probably it can be tested much better now > thanks to qgis_bench). > > My only experience here was the WMS benchmark 2011 with many layers and a > lot of expressions (osm data, a lot of classification rules, many layers). > For requests with a lot of features in view, expression evaluation showed up > considerably in the profiler, both in QGIS server and UMN mapserver. Yes, > feature fetching wasn't considered (still cachegrind) and I don't have the > cachegrind dumps at hand. However, it still shows that there are use-cases > where evaluation is not neglectable.
Hi Marco which implementation of expressions has been used in the benchmark - the old one (search strings) or the new one? If you have some saved callgrind dumps, I could have a look whether there are any issues that could be optimized easily. If there are serious speed problems, then we could start considering a better performing engine. Anyway as I written in my earlier mail, there may be issues with with supporting 3-value logic. Regards Martin _______________________________________________ Qgis-developer mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-developer
