Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Hi all, I'm happy to inform you that Phil (main PyQt maintainer) just announced that QtXml is going to be reincluded in the PyQt5 bindings. You may therefore happily continue to use QDomDocument and friends as much as you like and ignore my original request. Sorry for the noise Matthias On 12/03/2014 04:12 PM, Matthias Kuhn wrote: Hi, As of Qt5, QtXml is no longer actively maintained [1] PyQt5 does not even support it. It will be a reasonably big undertaking to migrate any occurrence of QDomDocument etc. to QXMLStreamWriter and QXMLStreamReader (our whole project saving and loading engine is based on this). And when we do this we will likely have to increase the major version number of QGIS. In order not to introduce more work, please consider using QXMLStreamWriter and QXMLStreamReader for new code you write that involves parsing or producing XML. That does not concern working on code that is based on code that is currently based on QtXml methods. Thank you, Matthias [1] http://qt-project.org/doc/qt-5/qtxml-module.html#details ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Hi Régis, On 12/04/2014 05:18 PM, Régis Haubourg wrote: Slowness is painfull also on project save, and I guess this is mainly the xml issue there. I'm with Marco there. On project save there is also a lot of code involved apart from XML and to attribute performance responsibility we need good evidence first. If there is a performance issue that you would like to tackle, I would start with profiling this process and only after decide where the best benefit can be achieved. Matthias ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Hi Matthias, On Wed, 03. Dec 2014 at 16:46:11 +0100, Matthias Kuhn wrote: I didn't look at it in detail and just based this recommendation on the one from the QtXml documentation linked at the end of the original message. Is there something in particular you think we will be missing? If so, it might be good to start looking for alternative ways to go. We could just keep using it and fork it if need be. Any idea why it was discontinued? Jürgen -- Jürgen E. Fischer norBIT GmbH Tel. +49-4931-918175-31 Dipl.-Inf. (FH) Rheinstraße 13 Fax. +49-4931-918175-50 Software Engineer D-26506 Norden http://www.norbit.de QGIS release manager (PSC) GermanyIRC: jef on FreeNode signature.asc Description: Digital signature ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
On 4 December 2014 at 19:25, Jürgen E. j...@norbit.de wrote: Hi Matthias, On Wed, 03. Dec 2014 at 16:46:11 +0100, Matthias Kuhn wrote: I didn't look at it in detail and just based this recommendation on the one from the QtXml documentation linked at the end of the original message. Is there something in particular you think we will be missing? If so, it might be good to start looking for alternative ways to go. We could just keep using it and fork it if need be. Any idea why it was discontinued? This link [1] suggests that it hasn't been discontinued, it's just unmaintained, and isn't scheduled for removal. That doesn't solve the PyQt5 problem though... It's also worth noting that QtXml is very slow, which is noticeable on project load/save. Nyall [1] https://bugreports.qt-project.org/browse/QTBUG-32926 ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Thank you Jürgen and Nyall, On 04.12.2014 09:44, Nyall Dawson wrote: On 4 December 2014 at 19:25, Jürgen E. j...@norbit.de wrote: We could just keep using it and fork it if need be. Any idea why it was discontinued? This link [1] suggests that it hasn't been discontinued, it's just unmaintained, and isn't scheduled for removal. That doesn't solve the PyQt5 problem though... It's also worth noting that QtXml is very slow, which is noticeable on project load/save. I wrote a mail to the PyQt mailing list to ask about the status. In general I think it is preferable to stay close to upstream as in the long run mainenance effort is normally smaller. But in this case a fork of QtXml (or its python bindings) may indeed be a good option considering the amount of work and the API break involved. For no apparent benefits and no clear migration path outlined. Matthias ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
QtXml is really, damn slow. PyQt with QtXml is worst then lxml, just to make a comparison. Switching to a streamlined xml parser would be advisable, but I know it would a deep refactoring for a lot of QGIS's code. Maybe it should be considered within the next big refactorings (geometry, composer, etc.), but it won't be easy to find a sponsor specifically for this... giovanni Il 04/dic/2014 09:45 Nyall Dawson nyall.daw...@gmail.com ha scritto: On 4 December 2014 at 19:25, Jürgen E. j...@norbit.de wrote: Hi Matthias, On Wed, 03. Dec 2014 at 16:46:11 +0100, Matthias Kuhn wrote: I didn't look at it in detail and just based this recommendation on the one from the QtXml documentation linked at the end of the original message. Is there something in particular you think we will be missing? If so, it might be good to start looking for alternative ways to go. We could just keep using it and fork it if need be. Any idea why it was discontinued? This link [1] suggests that it hasn't been discontinued, it's just unmaintained, and isn't scheduled for removal. That doesn't solve the PyQt5 problem though... It's also worth noting that QtXml is very slow, which is noticeable on project load/save. Nyall [1] https://bugreports.qt-project.org/browse/QTBUG-32926 ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
On Thu, Dec 4, 2014 at 10:04 AM, G. Allegri gioha...@gmail.com wrote: QtXml is really, damn slow. PyQt with QtXml is worst then lxml, just to make a comparison. Switching to a streamlined xml parser would be advisable, but I know it would a deep refactoring for a lot of QGIS's code. Maybe it should be considered within the next big refactorings (geometry, composer, etc.), but it won't be easy to find a sponsor specifically for this... For a project at my organization, I used the standard python module XML.ElementTree and it seems really good and fast. It's very easy to read, modify, add elements... ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
On 04.12.2014 10:04, G. Allegri wrote: QtXml is really, damn slow. PyQt with QtXml is worst then lxml, just to make a comparison. Switching to a streamlined xml parser would be advisable, but I know it would a deep refactoring for a lot of QGIS's code. Maybe it should be considered within the next big refactorings (geometry, composer, etc.), but it won't be easy to find a sponsor specifically for this... Do we have a real-world example of where we hit this performance issue? Considering a sponsor: it might be packaged in a proposal of a native project file format that also supports storing layers. That requires an abstraction of the project file and has a new feature that usually makes it easier to find funds. Matthias ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Considering a sponsor: it might be packaged in a proposal of a native project file format that also supports storing layers. You could potentially consider using a GeoPackage container as a base for that : - http://www.geopackage.org/spec/ - http://www.gdal.org/drv_geopackage.html It would cover storing vector layers. The QGIS specific parts could be stored in extension tables. -- Spatialys - Geospatial professional services http://www.spatialys.com ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Hi, agreed it's awfully slow on large project save (about 1 min sometimes for about 200 layers) +1 for refactoring qgs into a container able to store layers. That would give us a storing solution for memory layers, discussed previously. Cheers Régis -- View this message in context: http://osgeo-org.1560.x6.nabble.com/QtXml-is-no-longer-maintained-in-Qt5-tp5176248p5176425.html Sent from the Quantum GIS - Developer mailing list archive at Nabble.com. ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
It's also worth noting that QtXml is very slow, which is noticeable on project load/save. Is it really the xml parsing which is slow? I would have expected that xml parsing only is fast and the things QGIS is doing on project load are slow (e.g. restoring connections, creating print composers, ...). Did you do some profiling / testing related to xml parsing speed? Regards, Marco On 04.12.2014 09:44, Nyall Dawson wrote: On 4 December 2014 at 19:25, Jürgen E. j...@norbit.de wrote: Hi Matthias, On Wed, 03. Dec 2014 at 16:46:11 +0100, Matthias Kuhn wrote: I didn't look at it in detail and just based this recommendation on the one from the QtXml documentation linked at the end of the original message. Is there something in particular you think we will be missing? If so, it might be good to start looking for alternative ways to go. We could just keep using it and fork it if need be. Any idea why it was discontinued? This link [1] suggests that it hasn't been discontinued, it's just unmaintained, and isn't scheduled for removal. That doesn't solve the PyQt5 problem though... It's also worth noting that QtXml is very slow, which is noticeable on project load/save. Nyall [1] https://bugreports.qt-project.org/browse/QTBUG-32926 ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer -- Dr. Marco Hugentobler Sourcepole - Linux Open Source Solutions Weberstrasse 5, CH-8004 Zürich, Switzerland marco.hugentob...@sourcepole.ch http://www.sourcepole.ch Technical Advisor QGIS Project Steering Committee ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
On Thu, Dec 4, 2014 at 1:44 PM, Marco Hugentobler marco.hugentob...@sourcepole.ch wrote: Is it really the xml parsing which is slow? I would have expected that xml parsing only is fast and the things QGIS is doing on project load are slow (e.g. restoring connections, creating print composers, ...). Did you do some profiling / testing related to xml parsing speed? I agree with Marco. The major slowdown here is when QGIS connects to WMS/Postgis layers, not opening a simple XML file... We could be very careful about false problems, as stated by Donald Knuth: We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Slowness is painfull also on project save, and I guess this is mainly the xml issue there. -- View this message in context: http://osgeo-org.1560.x6.nabble.com/QtXml-is-no-longer-maintained-in-Qt5-tp5176248p5176498.html Sent from the Quantum GIS - Developer mailing list archive at Nabble.com. ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
[Qgis-developer] QtXml is no longer maintained in Qt5
Hi, As of Qt5, QtXml is no longer actively maintained [1] PyQt5 does not even support it. It will be a reasonably big undertaking to migrate any occurrence of QDomDocument etc. to QXMLStreamWriter and QXMLStreamReader (our whole project saving and loading engine is based on this). And when we do this we will likely have to increase the major version number of QGIS. In order not to introduce more work, please consider using QXMLStreamWriter and QXMLStreamReader for new code you write that involves parsing or producing XML. That does not concern working on code that is based on code that is currently based on QtXml methods. Thank you, Matthias [1] http://qt-project.org/doc/qt-5/qtxml-module.html#details ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Hi Matthias It will be a reasonably big undertaking to migrate any occurrence of QDomDocument etc. to QXMLStreamWriter and QXMLStreamReader From a quick look, it seems QXMLStreamReader is more like a SAX parser. If so, it is not a full replacement for the DOM classes. Regards, Marco On 03.12.2014 16:12, Matthias Kuhn wrote: Hi, As of Qt5, QtXml is no longer actively maintained [1] PyQt5 does not even support it. It will be a reasonably big undertaking to migrate any occurrence of QDomDocument etc. to QXMLStreamWriter and QXMLStreamReader (our whole project saving and loading engine is based on this). And when we do this we will likely have to increase the major version number of QGIS. In order not to introduce more work, please consider using QXMLStreamWriter and QXMLStreamReader for new code you write that involves parsing or producing XML. That does not concern working on code that is based on code that is currently based on QtXml methods. Thank you, Matthias [1] http://qt-project.org/doc/qt-5/qtxml-module.html#details ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer -- Dr. Marco Hugentobler Sourcepole - Linux Open Source Solutions Weberstrasse 5, CH-8004 Zürich, Switzerland marco.hugentob...@sourcepole.ch http://www.sourcepole.ch Technical Advisor QGIS Project Steering Committee ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] QtXml is no longer maintained in Qt5
Hi Marco, I didn't look at it in detail and just based this recommendation on the one from the QtXml documentation linked at the end of the original message. Is there something in particular you think we will be missing? If so, it might be good to start looking for alternative ways to go. Regards, Matthias On 03.12.2014 16:24, Marco Hugentobler wrote: Hi Matthias It will be a reasonably big undertaking to migrate any occurrence of QDomDocument etc. to QXMLStreamWriter and QXMLStreamReader From a quick look, it seems QXMLStreamReader is more like a SAX parser. If so, it is not a full replacement for the DOM classes. Regards, Marco On 03.12.2014 16:12, Matthias Kuhn wrote: Hi, As of Qt5, QtXml is no longer actively maintained [1] PyQt5 does not even support it. It will be a reasonably big undertaking to migrate any occurrence of QDomDocument etc. to QXMLStreamWriter and QXMLStreamReader (our whole project saving and loading engine is based on this). And when we do this we will likely have to increase the major version number of QGIS. In order not to introduce more work, please consider using QXMLStreamWriter and QXMLStreamReader for new code you write that involves parsing or producing XML. That does not concern working on code that is based on code that is currently based on QtXml methods. Thank you, Matthias [1] http://qt-project.org/doc/qt-5/qtxml-module.html#details ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
