[mapserver-dev] Implement msPostgisLayerGetExtent

[Tamas Szekeres]

2013/12/31 thomas bonfort <thomas.bonfort at gmail.com>

> Steve,
> This function is called to produce the capabilities document, in order
> to provide the client with information as to what the extent for each
> layer is. The provided patch is wanted/usefull, because some clients
> (namely qgis) are smart and will not request layers for extents that
> are outside the advertised extents; in the case where the advertized
> extents are incorrect then you can imagine that this leads to
> difficult to debug unexpected behavior. On the other hand, the
> provided patch is problematic because it may cause capabilities
> requests to take minutes or more to complete given that the st_extent
> call may take ages to complete. The simple workaround is to add an
> EXTENT to each layer, however this requires a manual intervention and
> was not needed beforehand.
>
>
That was not needed by the Postgis driver, but needed for the other drivers
where getExtent has already been implemented. I would not agree to keep
this kind of differences between the drivers. Either have this implemented
for all or for none of them.

As far as I can see in the discussion, a global setting to disable the
driver extent calculation for the GetCapabilities request would be a good
consensus, isn't it?


Tamas
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