[Qgis-developer] guestimating plug-in dev time?
Rémi Cura
remi.cura at gmail.com
Tue Jan 20 00:36:59 PST 2015
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>:
> 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> 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>>:
>>>>
>>>> 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> 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>> 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>>:
>>>>
>>>> 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>> 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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