Andrea Aime wrote: > Jody Garnett ha scritto: >> I have recently been building up graphs from WFS data; and have been >> experiencing some interesting performance characteristics - and I am >> wondering if they are expected ... >> >> In order to build up a graph ... >> 1. I request the features in a region using a normal WFS 1.0.0 >> GetFeatures request. >> 2. For the first 30 seconds the server performance logs show that >> GeoServer is using up a full core; and postgis is using a small >> percentage of another core. During this time no data is being >> transmitted to the client. >> 3. At this point the client starts GeoServer starts sending data to >> the client; GeoServer remains using a full core; and postgis is using >> a small percentage of another core. >> >> I went into the web.xml and confirmed that SPEED was set as the >> policy ... is this the case of needing to issue the postgis request >> twice? once to calculate the bounds and again to grab and transmit >> the data? If so can we avoid this step by assuming the bounds >> provided during the request "contain" the resulting data? > > Uh, this is complex. > First off, in 1.6.x we actually do 3 queries. The first one is a count, > to make sure we don't return too many features. It's only needed > in case you have multiple Query elements (to respect the global max > features request) and I've optimized it out in 1.7.0-RC3, no luck > for 1.6.x, that series is dead. :-) > The second one is about the bounds, and no, we cannot return the > request bounds, the bounds we return are supposed to be the > bounds of the feature collection. But we have a flag in WFS/content > that allows the result to avoid the bounds element altogether, > and it seems we're not honouring it anymore (can you open a jira issue > about it?). I am just leaving for the day; so I missed my chance to open a Jira. > On 1.7.x I double checked that SPEED is used for the benchmarks, but > on 1.6.x it's not the first report I heard of that makes me thing > for some reason file strategy is used instead. Yet I've just tried > with my 1.6.x checkout and with SPEED configured my debugger stops > only in SpeedStrategy... > > It's also quite strange that you see GeoServer peg the CPU, count and > bounds should use lots of Postgis time instead. It is strange; but the other developer here confirms it - geoserver was using a full core. > Can you enable GEOTOOLS_DEVELOPER_LOGGING and see what's taking so > long as it goes? > > Stupid question but... you do have a spatial index on that data, right? not a stupid question; that is what was wrong yesterday :-)
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