[Qgis-developer] guestimating plug-in dev time?

Andreas Neumann a.neumann at carto.net
Tue Jan 20 00:46:49 PST 2015


Hi Rémi,

Good to hear. Note that 2.3 was the dev version and not the stable 
version. 2.4  was stable, then 2.6, 2.8, etc.

Andreas

On 20.01.2015 09:36, Rémi Cura wrote:
> Many thanks for all the answers !
> The new version (2.6) is way more stable than 2.3 regarding postgis table.
> I'll do some torture test and submit tickets if I find any problem.
> Cheers,
> Rémi-C
>
> 2015-01-19 13:31 GMT+01:00 George Silva <georger.silva at gmail.com 
> <mailto:georger.silva at gmail.com>>:
>
>     I also have a lot of experience with a large number of users
>     (around 15) editing a central database with PostGIS. No problems
>     there.
>
>     Remi, the development time for this would be around a day. If you
>     wish to outsource that job, I have some experience with QGIS
>     Plugins and I could develop that for you.
>
>     George
>
>     On Mon, Jan 19, 2015 at 10:29 AM, Bernhard Ströbl
>     <bernhard.stroebl at jena.de <mailto:bernhard.stroebl at jena.de>> wrote:
>
>         Hi Andreas,
>
>         I do not think that multi-core rendering is the issue here as
>         Remi mentions to have experienced crashes since QGIS 1.8.
>
>         Remi,
>         I am using QGIS with Postgres/PostGIS with some dozens of
>         users on a central database _without_ any issues in QGIS
>         (except the multi-core issue Andreas mentioned). So do share
>         your problems together with relevent parts of your data base
>         so they can beanalyzed.
>
>         Bernhard
>
>         Am 19.01.2015 13:19, schrieb Andreas Neumann:
>
>             Hi Remi,
>
>             Regarding crashes with Postgis: do you have multithreading
>             with a lot of
>             CPU cores active? I am experiencing crashes if more than 2
>             cores are
>             active. Try limiting to 2 CPU cores and see if this helps.
>
>             Still trying to investigate this issue with the devs.
>
>             Besides the above issue, editing with Postgis works stable
>             for me -
>             certainly not as many crashes as you say you have.
>
>             Please do not ignore the crashes but try to report them so
>             that the devs
>             can do something about it.
>
>             Andreas
>
>             On 19.01.2015 11:57, Rémi Cura wrote:
>
>                 I think a more global solution is possible.
>                 After all when you load a postgis layer in qgis, if
>                 somebody else
>                 changes it, the view is not refreshed, which is
>                 annoying (and
>                 sometimes dangerous because you may edit old data).
>
>                 It would be easy to ad this (which would also work for
>                 my case) using
>                 the LISTEN / NOTIFY feature of postgres.
>
>                 Basically when selecting a table as a new qgis layer, you
>                 automatically add a triger to it.
>                 The trigger will be fired at any change
>                 (create/delete/update).
>                 The trigger would simply send a message to qgis via
>                 NOTIFY.
>                 example : "NOTIFY qgis_change_XXXX ;", where XXXX is a
>                 unique id.
>                 Of course qgis would be listening, which is very
>                 simple in python
>                 (import psycopg2;
>                 conn = psycopg.connect(my_database_string)
>                 conn.autocommit(1)
>                 curs = conn.cursor()
>                 curs.execute("LISTEN qgis_change_XXXX;"))
>
>                 Of course one would need a mechanism to remove this
>                 trigger when not
>                 necessary (for instance, name the channel
>                 "qgis_change_/time_stamp/",
>                 delete channel too old automatically, and change
>                 channel periodically
>                 (20 in for instance)).
>
>                 I don't know if from a security point of view it would
>                 be possibe
>                 tough (would require the permission to create a trigger).
>                 I don't know if typical qgis user have the right to
>                 create trigger on
>                 database they use.
>
>                 I use a lot of different version of QGIS and I can
>                 guarantee at least
>                 a dozen crash a day with version 1.8 to 2.3,
>                 plus pending transaction with postgis whenever the
>                 crash occurs.
>                 I'm installing 2.6 to see if postgis layers are less
>                 fragile right now ^^
>
>                 Cheers,
>                 Rémi-C
>
>                 2015-01-19 11:29 GMT+01:00 Martin Dobias
>                 <wonder.sk at gmail.com <mailto:wonder.sk at gmail.com>
>                 <mailto:wonder.sk at gmail.com
>                 <mailto:wonder.sk at gmail.com>>>:
>
>                     I see - indeed QGIS would need to do quite some
>                 database
>                     inspection to understand that layer A and layer B
>                 are related.
>                     This should be however also easy to address in a
>                 custom plugin.
>
>                     It is surprising to me that you say PostGIS layers
>                 are fragile in
>                     QGIS - they are very commonly used by lots of
>                 people and we
>                     haven't heard about crashes in the issue tracker.
>                 If you do
>                     experience crashes please consider filing reports
>                 on hub.qgis.org <http://hub.qgis.org>
>                     <http://hub.qgis.org> with instructions on how to
>                 replicate them.
>
>                     Regards
>                     Martin
>
>
>                     On Mon, Jan 19, 2015 at 5:18 PM, Rémi Cura
>                 <remi.cura at gmail.com <mailto:remi.cura at gmail.com>
>                     <mailto:remi.cura at gmail.com
>                 <mailto:remi.cura at gmail.com>>> wrote:
>
>                         Thanks Martin,
>                         one day to several days feel like a very
>                 reasonnable order of
>                         magnitude.
>
>                         QGis is not refreshing the view because when
>                 editing layer A
>                         the postgis data base automatically also edit
>                 layer B.
>                         I don't think qgis has a mechanism of tracking
>                 dbchanges (it
>                         would be possible tough).
>                         Morevover PostGIS layer are still "fragile" in
>                 qgis (crashes
>                         often).
>
>                         Thanks for the help,
>                         Cheers
>                         Rémi-C
>
>                         2015-01-19 10:56 GMT+01:00 Martin Dobias
>                 <wonder.sk at gmail.com <mailto:wonder.sk at gmail.com>
>                         <mailto:wonder.sk at gmail.com
>                 <mailto:wonder.sk at gmail.com>>>:
>
>                             Hi Remi
>
>                             Such plugin should be quite easy to write
>                 - I would assume
>                             up to one day of work for an experienced
>                 pyqgis developer.
>                             For a newcomer it may take few more days
>                 to get familiar
>                             with the API, tools, environment and so on.
>
>                             For the refresh of rendering after
>                 geometry editing - that
>                             should work out of the box and I would
>                 consider it a bug
>                             if it does not.
>
>                             Regards
>                             Martin
>
>
>                             On Mon, Jan 19, 2015 at 3:16 PM, Rémi Cura
>                             <remi.cura at gmail.com
>                 <mailto:remi.cura at gmail.com>
>                 <mailto:remi.cura at gmail.com
>                 <mailto:remi.cura at gmail.com>>> wrote:
>
>                                 Hello dear list.
>                                 I'm usually active on the postgis or
>                 postgres list,
>                                 but today I would like to ask a
>                 question regarding dev
>                                 time.
>
>                                 In your opinion,
>                                 How much time would be needed to write
>                 a plugin for
>                                 multiple versions of qgis (2.2 to
>                 current 2.6) doing 3
>                                 simple things :
>                                  - auto commit the edition of geometry
>                 when in edition
>                                 mode (no need to click on save 
>                 changes each time)
>                                  - force refresh of rendering after
>                 edition of a geometry
>                                  - every camera changes (zoom or
>                 position), send a sql
>                                 query containing user name and
>                 geometry of view (a
>                                 rectangle in wkt for instance).
>
>                                 I can estimate this at my poor
>                 qgis-dev level, but I
>                                 would like to have the timing for an
>                 expert qgis dev.
>
>                                 Many thanks,
>
>                                 Remi-C
>
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>
>
>
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>
>     -- 
>     George R. C. Silva
>     SIGMA Consultoria
>     ----------------------------
>     http://www.consultoriasigma.com.br/
>
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