Regarding Firefox: interesting; I see at least 50% of tile requests aborted, so it's working for me. I'm in Australia with ~200ms round trip time; I'm guessing you have a low RTT to your tile server which might affect this.
Regarding Chrome: I see the problem now, it looks like a bad interaction with continuous zoom. I'll file a bug internally. If you'd like to track progress on the issue, please file an issue in the issue tracker: http://code.google.com/p/gmaps-api-issues/. Thanks Ben On Wed, Jan 26, 2011 at 11:30 AM, John Laur <[email protected]> wrote: > Ben, > > I am seeing the behavior in Chrome and using the Network tab to check > the issue. If I load my map with a single tile overlay (ImageMapType) > requests queue for all tiles at all zoom levels, and the requests wait > to complete. In fairness *sometimes* i can zoom fast enough that > requests for an entire (or partial) layer are skipped, but for sure I > never see requests that begin and are aborted. The base tiles are also > loaded from google for all layers, but since they never have to be > generated and are smaller in file size, the problem is not visible. > > If I zoom from the my map's default zoom 5 in to its max zoom of 17, > the network pane will report the following times for the request for a > tile at layer 5: > > Conversely a tile at layer 5 has the following profile: > > Proxy 0, Blocking 0, Sending 0, Waiting 76ms, Receiving 209ms > > But by the time a layer 17 file is requested so many pending requests > have built up progressively to a much longer blocking time: > > Proxy 0, Blocking 6.08s, Sending 0, Waiting 276ms, Receiving 0 > > Currently, I am requesting all of my overlay tiles using the same > hostname. I do understand that I could use one hostname per layer and > this would allow more concurrent connections and the ability of the > browser to immediately initiate tile requests in a new layer without > blocking, but only so long as the browser will still be willing to > open new requests. It also introduces some other problems -- the load > to generate all the interim tiles still unnecessarily goes to the > servers. I have actually tested the multiple hostnames per layer and > it helps a bit but not enough, and doesn't really solve the core > problem. > > In firefox I do occasionally see Aborted requests in firebug, but > still most of the time I see hundreds of lines with spinners as the > downloads for each interim layer complete. > > John > > On Jan 25, 4:42 pm, Ben Appleton <[email protected]> wrote: > > Hi John, > > > > The API will initiate requests for tiles on screen, but cancels any > > in-flight requests after you zoom in again. It should not wait until > pending > > requests are satisfied. Further, your browser will limit the number of > > concurrent requests to your tile server, so your tile server should not > have > > to generate every tile during a scrollwheel zoom over multiple zoom > levels. > > Different browsers use different limits here. > > > > For example, if I loadhttp:// > code.google.com/apis/maps/documentation/javascript/examples/ma... > > Firefox with Firebug enabled, then scrollwheel zoom a few zoom levels, > > Firebug's Net tab reports many canceled tile requests and the final tiles > > appear reasonably fast. > > > > Which browser are you using? Can you confirm that tile requests are never > > being cancelled? > > > > Thanks > > Ben > > > > > > > > > > > > > > > > On Wed, Jan 26, 2011 at 2:38 AM, John Laur <[email protected]> wrote: > > > Hello, > > > > > I'm new to the group here; hello everyone. > > > > > I'm trying to figure out a technique for speeding up tile loading > > > performance for a custom image tile overlay. The trouble is that when > doing > > > a fast zoom with the mouse wheel or by rapidly clicking zoom in/out > buttons > > > the API will queue a bunch of requests for layers that have been > "zoomed > > > through" and loading the overlay for the current layer will not > actually > > > happen until these pending requests are satisfied. Initially I thought > > > Google was doing some magic with its base tile set to influence the > > > retrieval order of the base tiles during zooms, but upon closer > inspection > > > it appears they are simply servicing the tile requests with ridiculous > > > speed. > > > > > Since we are dynamically generating tiles, we can't hope to achieve a > > > similar result with ImageMapType by reducing latency alone; best we are > > > doing is about 100ms/tile. However we are able to horizontally scale > our > > > tile generation, so are there alternative techniques we can try? My > initial > > > thought is to use a different http hostname per layer to allow the > browser > > > to initiate immediate requests upon zooming to a layer, but there are > some > > > drawbacks to this approach on the server end. Another possibility might > be > > > to create an entirely new version of ImageMapType that performs better > with > > > a high-latency and highly-parallel tile generation, but that seems like > a > > > lot of work to jump into without first examining alternatives. > > > > > Thanks, > > > John Laur > > > > > -- > > > You received this message because you are subscribed to the Google > Groups > > > "Google Maps JavaScript API v3" group. > > > To post to this group, send email to > > > [email protected]. > > > To unsubscribe from this group, send email to > > > [email protected]<google-maps-js-api-v3%[email protected]><google-maps-js-api-v3%2B > [email protected]> > > > . > > > For more options, visit this group at > > >http://groups.google.com/group/google-maps-js-api-v3?hl=en. > > -- > You received this message because you are subscribed to the Google Groups > "Google Maps JavaScript API v3" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-maps-js-api-v3%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-maps-js-api-v3?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google Maps JavaScript API v3" group. 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