[Geoserver-devel] GeoServer WFS 2.0 limitations

Justin, perhaps you could submit a WFS 2 change request to encourage OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
It's just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61+-+WFS+2.0
"WFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation."

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

Similar issues have been brought up on the wfs-dev list I believeā€¦ and the spec writers have been open to amending them. There is also a constraint in the capabilities document in which one can declare whether paging is transaction safeā€¦ and we set that to falseā€¦ so perhaps the spec is poorly worded perhaps. Regardless though it seems pointless if all the legitimate implementations of wfs 2.0 donā€™t implement it.

On Tue, Oct 25, 2011 at 4:15 AM, Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com wrote:

Justin, perhaps you could submit a WFS 2 change request to encourage OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
Itā€™s just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61Ā±+WFS+2.0
ā€œWFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation.ā€

ā€“
Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

If you have time to submit a couple of bullet points and a link to your GSIP 61 page on the OGC web form below, you will ensure that the OGC SWG are at least aware of your findings as the principal implementer of GeoServer WFS 2.0. I suspect that they will find your work most useful.

If you lack the time and are willing to risk my misinterpretation, please let me know and I will submit your findings on behalf of the project.

Kind regards,
Ben.

On 25/10/11 15:26, Justin Deoliveira wrote:

Similar issues have been brought up on the wfs-dev list I believe... and the spec writers have been open to amending them. There is also a constraint in the capabilities document in which one can declare whether paging is transaction safe... and we set that to false... so perhaps the spec is poorly worded perhaps. Regardless though it seems pointless if all the legitimate implementations of wfs 2.0 don't implement it.

On Tue, Oct 25, 2011 at 4:15 AM, Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com> wrote:
Justin, perhaps you could submit a WFS 2 change request to encourage OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
It's just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61+-+WFS+2.0
"WFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation."

--
Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

--
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

On Tue, Oct 25, 2011 at 8:35 AM, Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com wrote:

If you have time to submit a couple of bullet points and a link to your GSIP 61 page on the OGC web form below, you will ensure that the OGC SWG are at least aware of your findings as the principal implementer of GeoServer WFS 2.0. I suspect that they will find your work most useful.

If you lack the time and are willing to risk my misinterpretation, please let me know and I will submit your findings on behalf of the project.

Sure I will try to gather my thoughts on thisā€¦ at a client site this week so might not be until end of week. That said I trust your understanding of the issue so if you want to compile the list by all means.

Kind regards,
Ben.

On 25/10/11 15:26, Justin Deoliveira wrote:

Similar issues have been brought up on the wfs-dev list I believeā€¦ and the spec writers have been open to amending them. There is also a constraint in the capabilities document in which one can declare whether paging is transaction safeā€¦ and we set that to falseā€¦ so perhaps the spec is poorly worded perhaps. Regardless though it seems pointless if all the legitimate implementations of wfs 2.0 donā€™t implement it.

On Tue, Oct 25, 2011 at 4:15 AM, Ben Caradoc-DaviesBen.Caradoc-Davies@anonymised.com wrote:
Justin, perhaps you could submit a WFS 2 change request to encourage OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
Itā€™s just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61Ā±+WFS+2.0
ā€œWFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation.ā€

ā€“
Ben Caradoc-DaviesBen.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

ā€“
Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

That would be great!

On 26/10/11 14:10, Justin Deoliveira wrote:

Sure I will try to gather my thoughts on this... at a client site this week so might not be until end of week.

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

Justin,

did you submit your GSIP 61 findings to the OGC WFS/FES SWG? It has started meeting. The web form is below (the link provided by Simon). I am sure the group will appreciate your input.

I am an observer on the SWG. I have raised the startIndex issue (clarify zero or one-based index).

Kind regards,
Ben.

On 26/10/11 14:43, Ben Caradoc-Davies wrote:

That would be great!

On 26/10/11 14:10, Justin Deoliveira wrote:

Sure I will try to gather my thoughts on this... at a client site this
week so might not be until end of week.

On 25/10/11 15:35, Ben Caradoc-Davies wrote:

If you have time to submit a couple of bullet points and a link to your
GSIP 61 page on the OGC web form below, you will ensure that the OGC SWG
are at least aware of your findings as the principal implementer of
GeoServer WFS 2.0. I suspect that they will find your work most useful.

If you lack the time and are willing to risk my misinterpretation,
please let me know and I will submit your findings on behalf of the
project.

Kind regards,
Ben.

On 25/10/11 15:26, Justin Deoliveira wrote:

Similar issues have been brought up on the wfs-dev list I believe...
and the spec writers have been open to amending them. There is also a
constraint in the capabilities document in which one can declare
whether paging is transaction safe... and we set that to false... so
perhaps the spec is poorly worded perhaps. Regardless though it seems
pointless if all the legitimate implementations of wfs 2.0 don't
implement it.

On Tue, Oct 25, 2011 at 4:15 AM, Ben
Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com> wrote:
Justin, perhaps you could submit a WFS 2 change request to encourage
OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
It's just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61+-+WFS+2.0
"WFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation."

--
Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

--
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

No I never didā€¦ it was something that fell off. Any chance we can just point them at the GSIP? Not sure i have the time to interact with the working group unfortunately.

On Thu, Jan 19, 2012 at 12:22 AM, Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com wrote:

Justin,

did you submit your GSIP 61 findings to the OGC WFS/FES SWG? It has started meeting. The web form is below (the link provided by Simon). I am sure the group will appreciate your input.

I am an observer on the SWG. I have raised the startIndex issue (clarify zero or one-based index).

Kind regards,
Ben.

On 26/10/11 14:43, Ben Caradoc-Davies wrote:

That would be great!

On 26/10/11 14:10, Justin Deoliveira wrote:

Sure I will try to gather my thoughts on thisā€¦ at a client site this
week so might not be until end of week.

On 25/10/11 15:35, Ben Caradoc-Davies wrote:

If you have time to submit a couple of bullet points and a link to your
GSIP 61 page on the OGC web form below, you will ensure that the OGC SWG
are at least aware of your findings as the principal implementer of
GeoServer WFS 2.0. I suspect that they will find your work most useful.

If you lack the time and are willing to risk my misinterpretation,
please let me know and I will submit your findings on behalf of the
project.

Kind regards,
Ben.

On 25/10/11 15:26, Justin Deoliveira wrote:

Similar issues have been brought up on the wfs-dev list I believeā€¦
and the spec writers have been open to amending them. There is also a
constraint in the capabilities document in which one can declare
whether paging is transaction safeā€¦ and we set that to falseā€¦ so
perhaps the spec is poorly worded perhaps. Regardless though it seems
pointless if all the legitimate implementations of wfs 2.0 donā€™t
implement it.

On Tue, Oct 25, 2011 at 4:15 AM, Ben
Caradoc-DaviesBen.Caradoc-Davies@anonymised.com wrote:
Justin, perhaps you could submit a WFS 2 change request to encourage
OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
Itā€™s just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61Ā±+WFS+2.0
ā€œWFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation.ā€

ā€“
Ben Caradoc-DaviesBen.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

ā€“
Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

Justin,

the working group is yet to receive all the change requests and has been discussing which to discuss [1]. Looks like there are some that are similar to your concerns. When I have them, I will compare the change requests to GSIP 61 and see if there are any outstanding issues.

Kind regards,
Ben.

[1] "Treebeard: You must understand, young Hobbit, it takes a long time to say anything in Old Entish. And we never say anything unless it is worth taking a long time to say."
http://www.imdb.com/character/ch0074878/quotes

On 21/01/12 00:23, Justin Deoliveira wrote:

No I never did... it was something that fell off. Any chance we can just point them at the GSIP? Not sure i have the time to interact with the working group unfortunately.

On Thu, Jan 19, 2012 at 12:22 AM, Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com> wrote:
Justin,

did you submit your GSIP 61 findings to the OGC WFS/FES SWG? It has started meeting. The web form is below (the link provided by Simon). I am sure the group will appreciate your input.

I am an observer on the SWG. I have raised the startIndex issue (clarify zero or one-based index).

Kind regards,
Ben.

On 26/10/11 14:43, Ben Caradoc-Davies wrote:
That would be great!

On 26/10/11 14:10, Justin Deoliveira wrote:
Sure I will try to gather my thoughts on this... at a client site this
week so might not be until end of week.

On 25/10/11 15:35, Ben Caradoc-Davies wrote:
If you have time to submit a couple of bullet points and a link to your
GSIP 61 page on the OGC web form below, you will ensure that the OGC SWG
are at least aware of your findings as the principal implementer of
GeoServer WFS 2.0. I suspect that they will find your work most useful.

If you lack the time and are willing to risk my misinterpretation,
please let me know and I will submit your findings on behalf of the
project.

Kind regards,
Ben.

On 25/10/11 15:26, Justin Deoliveira wrote:
Similar issues have been brought up on the wfs-dev list I believe...
and the spec writers have been open to amending them. There is also a
constraint in the capabilities document in which one can declare
whether paging is transaction safe... and we set that to false... so
perhaps the spec is poorly worded perhaps. Regardless though it seems
pointless if all the legitimate implementations of wfs 2.0 don't
implement it.

On Tue, Oct 25, 2011 at 4:15 AM, Ben
Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com> wrote:
Justin, perhaps you could submit a WFS 2 change request to encourage
OGC to change the spec to what you were able to reasonably implement? :smiley:

-------- Original Message --------
Subject: RE: GeoServer WFS 2.0 limitations
Date: Mon, 24 Oct 2011 17:39:58 +0800
From: Simon Cox

Submit a WFS 2.0 Change Request to explicitly relax this requirement.
https://portal.opengeospatial.org/public_ogc/change_request.php
It's just a web form.

-----Original Message-----
From: Ben Caradoc-Davies
Sent: Monday, 24 October 2011 4:56 PM
To: Simon Cox
Subject: GeoServer WFS 2.0 limitations

FYI

http://geoserver.org/display/GEOS/GSIP+61+-+WFS+2.0
"WFS 2.0 adds the ability to page results of a GetFeature request via
the startIndex and maxFeatures parameters. The WFS specification
actually implies that a service must maintain consistent paging results
in the light of transactions, but such a restriction is very difficult
to implement and implies that the server be able to store large results
in memory, or maintain database transactions between requests which goes
against the stateless nature of WFS all together. For this reason we
ignore this requirement in our implementation."

--
Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

--
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

--
Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

--
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

Justin,

the only outstanding issue I can find in GSIP 61 is the bit where you say:

"WFS 2.0 adds the ability to page results of a GetFeature request via the startIndex and maxFeatures [sic, I think you mean count] parameters. The WFS specification actually implies that a service must maintain consistent paging results in the light of transactions, but such a restriction is very difficult to implement and implies that the server be able to store large results in memory, or maintain database transactions between requests which goes against the stateless nature of WFS all together. For this reason we ignore this requirement in our implementation."
http://geoserver.org/display/GEOS/GSIP+61+-+WFS+2.0

I can't find anything in the spec that *requires* consistent paging results across transactions (but then I know transactions least of all). Or do you think it is just a convenient omission? I can see why it would make sense, and also why it would be prohibitive to implement.

Next SWG meeting is on Wednesday; still time for me to squeeze in a last minute change request if necessary (for WFS 2.1).

Kind regards,
Ben.

On 01/02/12 14:07, Ben Caradoc-Davies wrote:

Justin,

the working group is yet to receive all the change requests and has been
discussing which to discuss [1]. Looks like there are some that are
similar to your concerns. When I have them, I will compare the change
requests to GSIP 61 and see if there are any outstanding issues.

Kind regards,
Ben.

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

Hey Ben,

Sorry for the late response. But if you look at Table 14 of the spec (section 8.3.5.3, page 53) you will notice a service constraint named ā€œPagingIsTransactionSafeā€, which is described as: ā€œSpecifies whether the server maintains transactional consistency between paging iterationsā€.

It is possible i am misunderstanding what this implies.

On Tue, Feb 21, 2012 at 1:52 AM, Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com wrote:

Justin,

the only outstanding issue I can find in GSIP 61 is the bit where you say:

ā€œWFS 2.0 adds the ability to page results of a GetFeature request via the startIndex and maxFeatures [sic, I think you mean count] parameters. The WFS specification actually implies that a service must maintain consistent paging results in the light of transactions, but such a restriction is very difficult to implement and implies that the server be able to store large results in memory, or maintain database transactions between requests which goes against the stateless nature of WFS all together. For this reason we ignore this requirement in our implementation.ā€
http://geoserver.org/display/GEOS/GSIP+61Ā±+WFS+2.0

I canā€™t find anything in the spec that requires consistent paging results across transactions (but then I know transactions least of all). Or do you think it is just a convenient omission? I can see why it would make sense, and also why it would be prohibitive to implement.

Next SWG meeting is on Wednesday; still time for me to squeeze in a last minute change request if necessary (for WFS 2.1).

Kind regards,
Ben.

On 01/02/12 14:07, Ben Caradoc-Davies wrote:

Justin,

the working group is yet to receive all the change requests and has been
discussing which to discuss [1]. Looks like there are some that are
similar to your concerns. When I have them, I will compare the change
requests to GSIP 61 and see if there are any outstanding issues.

Kind regards,
Ben.

ā€“
Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

Justin,

I think that the only obligation on a service that implements the paging profile is to specify in its capabilities document whether paging is consistent across transactions (7.7.4.4.2.1). Just set this to false and you are done.

Kind regards,
Ben.

On 22/02/12 23:35, Justin Deoliveira wrote:

Hey Ben,

Sorry for the late response. But if you look at Table 14 of the spec (section 8.3.5.3, page 53) you will notice a service constraint named "PagingIsTransactionSafe", which is described as: "Specifies whether the server maintains transactional consistency between paging iterations".

It is possible i am misunderstanding what this implies.

On Tue, Feb 21, 2012 at 1:52 AM, Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com> wrote:
Justin,

the only outstanding issue I can find in GSIP 61 is the bit where you say:

"WFS 2.0 adds the ability to page results of a GetFeature request via the startIndex and maxFeatures [sic, I think you mean count] parameters. The WFS specification actually implies that a service must maintain consistent paging results in the light of transactions, but such a restriction is very difficult to implement and implies that the server be able to store large results in memory, or maintain database transactions between requests which goes against the stateless nature of WFS all together. For this reason we ignore this requirement in our implementation."
http://geoserver.org/display/GEOS/GSIP+61+-+WFS+2.0

I can't find anything in the spec that *requires* consistent paging results across transactions (but then I know transactions least of all). Or do you think it is just a convenient omission? I can see why it would make sense, and also why it would be prohibitive to implement.

Next SWG meeting is on Wednesday; still time for me to squeeze in a last minute change request if necessary (for WFS 2.1).

Kind regards,
Ben.

On 01/02/12 14:07, Ben Caradoc-Davies wrote:
Justin,

the working group is yet to receive all the change requests and has been
discussing which to discuss [1]. Looks like there are some that are
similar to your concerns. When I have them, I will compare the change
requests to GSIP 61 and see if there are any outstanding issues.

Kind regards,
Ben.

--
Ben Caradoc-Davies<Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

--
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

FWIW, imho it should be possible to declare this and other service metadata on a per-FeatureType basis.
Iā€™m not sure, but it seems that the implementations that drive the spec work a lot different than GeoServer, like in if they work against a single ā€œbackendā€ hence having a fixed set of capabilities for all types.
Hence, in order not to sound like unneeded critic, I wonder what should I do as a community to help drive future versions of the spec.

0.02 or less.
Gabriel

On Wed, Feb 22, 2012 at 10:37 PM, Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com wrote:

Justin,

I think that the only obligation on a service that implements the paging
profile is to specify in its capabilities document whether paging is
consistent across transactions (7.7.4.4.2.1). Just set this to false and
you are done.

Kind regards,
Ben.

On 22/02/12 23:35, Justin Deoliveira wrote:

Hey Ben,

Sorry for the late response. But if you look at Table 14 of the spec (section 8.3.5.3, page 53) you will notice a service constraint named ā€œPagingIsTransactionSafeā€, which is described as: ā€œSpecifies whether the server maintains transactional consistency between paging iterationsā€.

It is possible i am misunderstanding what this implies.

On Tue, Feb 21, 2012 at 1:52 AM, Ben Caradoc-DaviesBen.Caradoc-Davies@anonymised.com wrote:
Justin,

the only outstanding issue I can find in GSIP 61 is the bit where you say:

ā€œWFS 2.0 adds the ability to page results of a GetFeature request via the startIndex and maxFeatures [sic, I think you mean count] parameters. The WFS specification actually implies that a service must maintain consistent paging results in the light of transactions, but such a restriction is very difficult to implement and implies that the server be able to store large results in memory, or maintain database transactions between requests which goes against the stateless nature of WFS all together. For this reason we ignore this requirement in our implementation.ā€
http://geoserver.org/display/GEOS/GSIP+61Ā±+WFS+2.0

I canā€™t find anything in the spec that requires consistent paging results across transactions (but then I know transactions least of all). Or do you think it is just a convenient omission? I can see why it would make sense, and also why it would be prohibitive to implement.

Next SWG meeting is on Wednesday; still time for me to squeeze in a last minute change request if necessary (for WFS 2.1).

Kind regards,
Ben.

On 01/02/12 14:07, Ben Caradoc-Davies wrote:
Justin,

the working group is yet to receive all the change requests and has been
discussing which to discuss [1]. Looks like there are some that are
similar to your concerns. When I have them, I will compare the change
requests to GSIP 61 and see if there are any outstanding issues.

Kind regards,
Ben.

ā€“
Ben Caradoc-DaviesBen.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

ā€“
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

ā€“
Ben Caradoc-Davies Ben.Caradoc-Davies@anonymised.com
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre


Virtualization & Cloud Management Using Capacity Planning
Cloud computing makes use of virtualization - but cloud computing
also focuses on allowing computing to be delivered as a service.
http://www.accelacomm.com/jaw/sfnl/114/51521223/


Geoserver-devel mailing list
Geoserver-devel@anonymised.comsts.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geoserver-devel

ā€“
Gabriel Roldan
OpenGeo - http://opengeo.org
Expert service straight from the developers.

On Sun, Mar 4, 2012 at 1:04 AM, Gabriel Roldan <groldan@anonymised.com> wrote:

FWIW, imho it should be possible to declare this and other service metadata
on a per-FeatureType basis.
I'm not sure, but it seems that the implementations that drive the spec work
a lot different than GeoServer, like in if they work against a single
"backend" hence having a fixed set of capabilities for all types.
Hence, in order not to sound like unneeded critic, I wonder what should I do
as a community to help drive future versions of the spec.

I always thought one of the reasons for WFS to exist was actually to hide
the fact the different feature types might be coming from different sources,
and make everything look uniform.

At the same time I agree the above vision has a quite the cost, in various ways:
- bringing up less capable data sources to have the same features as the
  most capable ones is costly
- working against some emulated, non native, feature (e.g., sorting
over large data set)
  has a runtime cost.

Thinking about the runtime costs, there are issue that extend beyond the
data source differences, given a single feature type some fields are indexed,
some are not, it's not the first time I hear people asking for ways to
limit acceptable
WFS filters so that they include at least one condition on a indexed field to
avoid killing the database on a long and hard sequential scan.
The same could be applied to styles posted along with a GetMap request (SLD 1.0
WMS extensions, &sld, &sld_body and so on)
Something similar could be said about WFS-T, maybe you have some editable
fields, and some others that are compute on the fly and are thus non editable.

Of course being able to specify all of the above on a per type basis would make
clients harder to build.

Cheers
Andrea

--
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead

Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy

phone: +39 0584 962313
fax: +39 0584 962313
mob: +39 339 8844549

http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.youtube.com/user/GeoSolutionsIT
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf

-------------------------------------------------------

On Sun, Mar 4, 2012 at 5:28 AM, Andrea Aime
<andrea.aime@anonymised.com> wrote:

On Sun, Mar 4, 2012 at 1:04 AM, Gabriel Roldan <groldan@anonymised.com> wrote:

FWIW, imho it should be possible to declare this and other service metadata
on a per-FeatureType basis.
I'm not sure, but it seems that the implementations that drive the spec work
a lot different than GeoServer, like in if they work against a single
"backend" hence having a fixed set of capabilities for all types.
Hence, in order not to sound like unneeded critic, I wonder what should I do

edit: "...what should _we_ do..."

as a community to help drive future versions of the spec.

I always thought one of the reasons for WFS to exist was actually to hide
the fact the different feature types might be coming from different sources,
and make everything look uniform.

Nobody is saying the opposite. I may be missing something, but how do
you distinguish an editable feature type from a read only one off the
capabilities document?

Anyways, we're taking the thread too off topic I guess.

Cheers,
Gabriel

At the same time I agree the above vision has a quite the cost, in various ways:
- bringing up less capable data sources to have the same features as the
most capable ones is costly
- working against some emulated, non native, feature (e.g., sorting
over large data set)
has a runtime cost.

Thinking about the runtime costs, there are issue that extend beyond the
data source differences, given a single feature type some fields are indexed,
some are not, it's not the first time I hear people asking for ways to
limit acceptable
WFS filters so that they include at least one condition on a indexed field to
avoid killing the database on a long and hard sequential scan.
The same could be applied to styles posted along with a GetMap request (SLD 1.0
WMS extensions, &sld, &sld_body and so on)
Something similar could be said about WFS-T, maybe you have some editable
fields, and some others that are compute on the fly and are thus non editable.

Of course being able to specify all of the above on a per type basis would make
clients harder to build.

Cheers
Andrea

--
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead

Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy

phone: +39 0584 962313
fax: +39 0584 962313
mob: +39 339 8844549

http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.youtube.com/user/GeoSolutionsIT
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf

-------------------------------------------------------

--
Gabriel Roldan
OpenGeo - http://opengeo.org
Expert service straight from the developers.

On Mon, Mar 5, 2012 at 4:10 AM, Gabriel Roldan <groldan@anonymised.com> wrote:

On Sun, Mar 4, 2012 at 5:28 AM, Andrea Aime
<andrea.aime@anonymised.com> wrote:

On Sun, Mar 4, 2012 at 1:04 AM, Gabriel Roldan <groldan@anonymised.com> wrote:

FWIW, imho it should be possible to declare this and other service metadata
on a per-FeatureType basis.
I'm not sure, but it seems that the implementations that drive the spec work
a lot different than GeoServer, like in if they work against a single
"backend" hence having a fixed set of capabilities for all types.
Hence, in order not to sound like unneeded critic, I wonder what should I do

edit: "...what should _we_ do..."

as a community to help drive future versions of the spec.

I always thought one of the reasons for WFS to exist was actually to hide
the fact the different feature types might be coming from different sources,
and make everything look uniform.

Nobody is saying the opposite. I may be missing something, but how do
you distinguish an editable feature type from a read only one off the
capabilities document?

That would need extensions to the current protocol of course.
Everything I suggested below would in fact, I should have been more explicit.

At the same time I agree the above vision has a quite the cost, in various ways:
- bringing up less capable data sources to have the same features as the
most capable ones is costly
- working against some emulated, non native, feature (e.g., sorting
over large data set)
has a runtime cost.

Thinking about the runtime costs, there are issue that extend beyond the
data source differences, given a single feature type some fields are indexed,
some are not, it's not the first time I hear people asking for ways to
limit acceptable
WFS filters so that they include at least one condition on a indexed field to
avoid killing the database on a long and hard sequential scan.
The same could be applied to styles posted along with a GetMap request (SLD 1.0
WMS extensions, &sld, &sld_body and so on)
Something similar could be said about WFS-T, maybe you have some editable
fields, and some others that are compute on the fly and are thus non editable.

Of course being able to specify all of the above on a per type basis would make
clients harder to build.

Cheers
Andrea

--
-------------------------------------------------------
Ing. Andrea Aime
GeoSolutions S.A.S.
Tech lead

Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy

phone: +39 0584 962313
fax: +39 0584 962313
mob: +39 339 8844549

http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://www.youtube.com/user/GeoSolutionsIT
http://www.linkedin.com/in/andreaaime
http://twitter.com/geowolf

-------------------------------------------------------

On 04/03/12 08:04, Gabriel Roldan wrote:

FWIW, imho it should be possible to declare this and other service metadata on a per-FeatureType basis.
I'm not sure, but it seems that the implementations that drive the spec work a lot different than GeoServer, like in if they work against a single "backend" hence having a fixed set of capabilities for all types.

The sweeping scope and authoritative voice of the standards might lead one to believe that the implementations behind them use the full scope of each standard. I have discovered that this is not the case. Standards reflect aspirational goals and foresighted estimates. For example, I was not able to find anyone who implements WFS 2.0 remote resolve.

Hence, in order not to sound like unneeded critic, I wonder what should I do as a community to help drive future versions of the spec.

(1) Submit change requests. This is a simple online form. Submissions can be as long or as short as you like. All are given consideration. This is the easiest way for non-OGC-members to contribute to the development of standards:
http://www.opengeospatial.org/standards/cr

(2) If you are a member (individual or corporate), you can join Standards Working Groups as an observer, or even a charter member. Here is the page for the WFS/FES SWG (OGC login required):
https://portal.opengeospatial.org/?m=projects&a=view&project_id=390

(3) Find an SWG member and persecute them mercilessly. :slight_smile:

Coming from the open source community, the OGC interpretation of "open" is a culture shock.

Kind regards,

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre

And I should note that the change request form is not just a nicety: it is a *requirement* that every change request, large or small, be submitted through the form, even if you are a member of the SWG, to ensure that proposals are available for all to see. This is a good thing.

On 06/03/12 09:29, Ben Caradoc-Davies wrote:

(1) Submit change requests. This is a simple online form. Submissions
can be as long or as short as you like. All are given consideration.
This is the easiest way for non-OGC-members to contribute to the
development of standards:
http://www.opengeospatial.org/standards/cr

--
Ben Caradoc-Davies <Ben.Caradoc-Davies@anonymised.com>
Software Engineer
CSIRO Earth Science and Resource Engineering
Australian Resources Research Centre