[mapguide-users] RE: Tooltip performance

Mon Nov 20 08:44:51 EST 2006

I Agree Willem.

The tooltips worked quick in mapguide 6.5. The only other option that would
be nice would be to prioritize them separately from layer display.
(sometimes there is a layer displayed on top that makes it kind of hard to
get the tooltip you want). I realize this is always going to be a contention
but if there were a priority you could remove some contention.

Brad

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From: Willem Schwarte [mailto:willem at giskit.nl] 
Sent: Monday, November 20, 2006 3:36 AM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: Tooltip performance
Importance: High

I would really like it if this tooltip thing, got its own routines. Then you
can just query the top layer and if this has a tooltip, break from routine,
else just query the next, till you get a tooltip.

Most maps will have more then 10 layers, so it seems a bit overkill to query
them all, when you just want the top layers tooltip.

And also don't let it depend on the selectability of the layer, you always
want to see a tooltip (if this property is filled).

Willem

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Van: Trevor Wekel [mailto:trevor.wekel at autodesk.com] 
Verzonden: vrijdag 17 november 2006 20:15
Aan: Jason Birch; users at mapguide.osgeo.org
Onderwerp: RE: [mapguide-users] RE: Tooltip performance

Hi Jason,

It looks as though we will need some API changes (HTTP Protocol, MgMap) to
implement this.  Since API changes are involved, should this be handled as
an RFC?

Thanks,

Trevor

  _____  

From: Jason Birch [mailto:Jason.Birch at nanaimo.ca] 
Sent: Friday, November 17, 2006 11:39 AM
To: users at mapguide.osgeo.org
Cc: Trevor Wekel
Subject: RE: [mapguide-users] RE: Tooltip performance

That seems sub-optimal.  

- It's spending extra cycles on layers that don't need to be queried.

- What happens if I have a layer which is not selectable, but for which I
want to return a maptip?

What would it take to change this?

Jason

  _____  

From: Trevor Wekel [mailto:trevor.wekel at autodesk.com] 
Sent: Friday, November 17, 2006 10:34
To: Jason Birch; users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: Tooltip performance

Hi Jason,

Looks as though we only use the selectability property currently.  The
routine is shared code with selection handling.

Trevor

  _____  

From: Jason Birch [mailto:Jason.Birch at nanaimo.ca] 
Sent: Friday, November 17, 2006 11:17 AM
To: users at mapguide.osgeo.org
Subject: RE: [mapguide-users] RE: Tooltip performance

Is it just layers that have had their selectability property cleared that
will be ignored, or will not setting a maptip have the same effect?

Jason

  _____  

From: Trevor Wekel [mailto:trevor.wekel at autodesk.com] 
Sent: Friday, November 17, 2006 10:15
To: Campbell, Keith A; users at mapguide.osgeo.org
Subject: [mapguide-users] RE: Tooltip performance

Hi Keith,

You can also disable selection for layers which do not require tooltips.  If
a layer is not selectable, it is not included in the query.

Thanks,

Trevor

  _____  

From: Trevor Wekel 
Sent: Friday, November 17, 2006 10:54 AM
To: 'Campbell, Keith A'; users at mapguide.osgeo.org
Subject: RE: Tooltip performance

Hi Keith,

You are correct with the basic flow of events for generating the tooltips.
The AJAX client sends the map coordinates of the point along with the map
name to the Web Extensions.  The Web Extensions in turn, forwards this
information to the Server.  Once at the server, all of the layers in the map
are queried to see if they have any features underneath the point.  Since
every layer is queried, the performance will depend on the number of layers
in the Map.  Each FeatureSource for each layer will be queried.  If you have
a number of layers from external databases, the database will be queried for
each layer.

Feature Service connection pooling and caching may help.  These are
controlled by the following settings in serverconfig.ini and should be
accessible from Server Admin.

[FeatureServiceProperties]

DataConnectionPoolSize = 20
DataConnectionPoolExcludedProviders = OSGeo.SDF,OSGeo.SHP
DataConnectionPoolEnabled = 1
DataCacheSize = 100
CacheSize = 100

Just as a side note, I think MapGuide 6.x handles tooltip generation client
side.  I don't think it goes back to the server so it will be less affected
by server load.

Thanks,

Trevor

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From: Campbell, Keith A [mailto:keith.campbell at atkinsglobal.com] 
Sent: Friday, November 17, 2006 6:53 AM
To: users at mapguide.osgeo.org
Subject: Tooltip performance

I'm finding that the performance of the tooltips is varying greatly and I'd
like to understand what is going on behind the scenes and therefore what
factors are affecting this.

Presumably when the cursor s moved over the map, a mouseover event is
triggered and this sends the position information and state of the layers is
sent back to the server via an xmlhttprequest. The web extensions are used
to identify what object on what layer is at the map location, and the
tooltip data is queried and returned to the client, which is then displayed.
So factors affecting this process will be what is happening on the client
machine, the network, and the server at the time the process occurs.

The performance seems to change a great deal from very good to unacceptably
slow (the user would give up). I find this change strange because other
applications (e.g. MapGuide 6.x) run from the same client to the same server
are not varying nearly as much. It is also strange in that the initial
request for the layout and subsequent requests for layer data are not
particularly slow when the tooltips are. Are there any settings which can be
altered to improve this? This kind of unreliability could almost rule this
technology out in my view.

Keith 

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