Hi Bruno, another list of known issues with SQLite/GeoPackage and SAMBA in particular https://trac.osgeo.org/gdal/wiki/UserDocs/SQLite
regards
robert
Am 06.05.20 um 12:00 schrieb Stefan Keller:
> Hi,
>
> This should be IMHO an issue of highest priority for QGIS.
>
> Jésahel wrote
>> I've created a script to deactivate wal on samba shares, because samba is
>> the main issue.
>> It contains this only line : QSettings().setValue("/qgis/walForSqlite3",
>> False)
> That's interesting. Are you sure it's Samba?
> SQLite FAQ [2] confirms that NFS has problems.
> Did not find issues on Samba, but file locking with fcntl is mentioned here
> [3].
>
> Goal should IMHO be that 1. No crash, 2. read-only multi-user access
> should be possible and 3. writing users must be warned if QGIS isn't
> able to exclusively open the file.
> And Jésahel script suggests, that at least point 1 and 2 are possible.
>
> Andreas wrote:
>> Unfortunately it is a known issue that Geopackages and QGIS are bad at
>> handling simultaneous write and even read requests
>> and developers are working on finding solutions (hopefully soon).
> The only issue I find on QGIS tracker is [1]. Am I missing something?
>
> :Stefan
>
> [1] https://github.com/qgis/QGIS/issues/23991
> [2] https://www.sqlite.org/faq.html#q5
> [3] https://www.samba.org/samba/docs/old/Samba3-HOWTO/locking.html
>
> Am Mi., 6. Mai 2020 um 10:42 Uhr schrieb Jésahel Benoist <[email protected]>:
>> Hi Bruno,
>>
>> I've worked a lot on this issue for two years now. I've started with sqlite
>> (that was faster and better) but finally I decided to migrate to geopackage.
>> It was painful at first but now it's OK. But it needs some rules.
>>
>> First, I've broken the original big geopackage files into smaller ones. The
>> users are advised to work only one by one on a specific thematic/file (read
>> access is possible).
>> I've created a script to deactivate wal on samba shares, because samba is
>> the main issue. It contains this only line :
>> QSettings().setValue("/qgis/walForSqlite3", False)
>> You should download some tools like Spatialite_GUI and SQLiteDatabaseBrowser
>> so that you can really work on the db and have better control. QGIS's
>> dbmanager is a bit limited and sometimes buggy for sqlite/geopackage,
>> especially with special chars.
>> Try to work with QGIS internal explorer, it's a tool that has good
>> export/import functions.
>> Backup files at least one time a day !
>>
>> Now with the covid I have created my own online postgis server so that we
>> can work at home without "help" of IT department and it's GREAT. Multi-user,
>> faster, smaller, stronger (lol). And some nice capabilities like spatial
>> filtering ! I highly recommend this.
>>
>> Questions for all : I've recently discovered this
>> https://gdal.org/user/virtual_file_systems.html#virtual-file-systems
>> Wouldn't it be possible to avoid samba's multi-users bug with vsi ?
>>
>> Jésahel
>>
>>
>>
>> Le mer. 6 mai 2020 à 09:12, Andreas Neumann <[email protected]> a écrit :
>>> Hi Bruno,
>>>
>>> Unfortunately it is a known issue that Geopackages and QGIS are bad at
>>> handling simultaneous write and even read requests and developers are
>>> working on finding solutions (hopefully soon). In single user scenarios
>>> Geopackages are fine. But Multiuser must be avoided, even for reading only,
>>> unfortunately.
>>>
>>> As to PostgreSQL vs. Postgis: Postgis is the spatial extension of
>>> PostgreSQL. If you need geometries (which I assume) than you will need
>>> Postgis.
>>>
>>> Andreas
>>>
>>> Am 06.05.20 um 08:58 schrieb [email protected]:
>>>
>>> Hi
>>>
>>> In my company we are five people who sometimes work with GIS, and we are
>>> moving from ArcGIS to QGIS (how cool is QGIS and SLYR!) and in this context
>>> from ESRI file geodatabase to geopackage. Today we run into serious issues
>>> when two people worked with the same geopackage. I was aware, that it is
>>> dangerous and unwise to edit the same geopackage from two different
>>> computers at the same time. But I did not expect both QGIS applications to
>>> crash immediately and the geopackage to get corrupted. I hoped to get a
>>> warning or simply not be able to enter edit mode (We later found out, that
>>> the corrupted geopackage could be recoveredby by adding a new table, this
>>> somehow fixed it. Whew!).
>>>
>>> Worse, I found that the same thing happens, when I open a QGIS project with
>>> a layer from a geopackage for display only (no edit mode), which is being
>>> edited by an other user on an other computer. Again, both QGIS application
>>> crashed immediately with data loss. Again, the non-responsive QGIS tasks
>>> could not be killed by windows taskmanager, only by restarting of the
>>> computers.
>>>
>>> We are using QGIS 3.12.2 on Windows 10. The Geopackages are located on a
>>> samba network share.
>>>
>>> My questions:
>>>
>>> 1. Is this setup that bad? Do you experience the same fatal consequences if
>>> someone loads a layer from a geopackage which is being edited by someone
>>> else? Is there something I do wrong or I that can do to improve the
>>> situation?
>>>
>>> 2. I realize, that we should probably move from geopackage to a database.
>>> Do we need PostGIS or can we use PostgreSQL? We don't need more
>>> functinality than a geopackage offers (exept multi user read/edit
>>> possibility and stability).
>>>
>>> Many thanks for some hints that put me in the right direction!
>>>
>>> Bruno
>>>
>>>
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