[QGIS-Developer] How to Prevent GeoPackage file from updating modified date when viewed in a Qgis project when it is not being edited

[Richard Duivenvoorde]

FYI: answered on Qgis-user list

Regards,

Richard Duivenvoorde

On 10-04-18 05:04, rjwillson at gmail.com wrote:
> Re-directing this post from qgis user list to developer list
> 
>  
> 
> *From:*rjwillson at gmail.com <rjwillson at gmail.com>
> *Sent:* Monday, April 9, 2018 15:25
> *To:* qgis-user at lists.osgeo.org
> *Subject:* How to Prevent GeoPackage file from updating modified date
> when viewed in a Qgis project when it is not being edited
> 
>  
> 
> I would really like to use and promote GeoPackage as the go to data
> format in my organization but I am having the following problem that I
> haven’t been able to solve.
> 
>  
> 
> When ever someone opens a Q template project that has a layer with a
> GeoPackage data source, the GeoPackage file (not its contents) will be
> altered and it will show that it has been updated in the Windows file
> manager. I have been told that this happens because the write ahead
> logging has been triggered (creation of *.wal and *.shm) files by simply
> viewing the contents of the GeoPackage in QGIS and/or in Intramaps Roam
> (works on top of QGIS for tablets).
> 
>  
> 
> This is problematic because most users in our organization will then
> look at the windows modified date time stamp and conclude that the
> file’s contents have been modified. Additionally, all of the GIS layers
> are stored in Dropbox and subsequently Dropbox concludes that the file
> has been modified and it re-uploads a new copy of the GeoPackage. When
> it is a large GeoPackage > 1 GB in size this is quite problematic and
> causes a cascade of uploads and downloads.
> 
>  
> 
> Over the last few months I have tried to suppress this modification for
> the large GeoPackages in our system in the following ways: (1) make the
> layer read only in the QGIS project (no effect); (2) make the Dropbox
> folder read only for all users except the Dropbox administrator (this is
> effective for the large base layers); (3) change the properties of the
> file in windows to read only (effective for the Dropbox administrator);
> and (4) add a user variable to the windows system environment variables:
> OGR_SQLITE_JOURNAL = DELETE (effective for QGIS but not for Intramaps Roam)
> 
>  
> 
> Combining 2, 3, and 4 allows me to use GeoPackage for layers I can
> ensure are placed in the read-only Dropbox folders.
> 
>  
> 
> It is likely that my organization will never need the simultaneous
> editing of datasets that is facilitated by Write-Ahead Logging, but I
> would really like to be able to replace shapefiles and File geodatabases
> with GeoPackages in all of our projects going forward.
> 
>  
> 
> Therefore, is there a simpler way to suppress the write ahead logging
> behaviour that causes the files to believe they have been updated for
> all GeoPackages created in QGIS or used in a QGIS project?
> 
>  
> 
> If there is currently no way to do this, how do others adjust their
> workflows so that they know when the contents of a GeoPackage have
> really been modified versus just viewed by other users?
> 
>  
> 
> Rob
> 
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> 
> 
> 
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