Hi all,
We had the same experience in a project of ours. Multiple users with
read-only access to a gpkg on a (Windows) network share. The results
were freezes on unloading the layer (e.g. closing QGIS or opening
another project) on system A until system B would have closed the QGIS
layer there. The behavior seemed surprising to me and on first sight I'd
have put it more into the category "bug" rather than "feature".
Good news, this behavior could be changed by switching the sqlite
journal mode to delete (environment variable OGR_SQLITE_JOURNAL=DELETE).
QGIS and OGR use gpkg in WAL mode by default. Fun fact: this is not
supported on network drives, as documented on
https://www.sqlite.org/wal.html :
> All processes using a database must be on the same host computer; WAL
does not work over a network filesystem
I did not test what happens if only *some* of the accessing systems use
DELETE and others use WAL, nor did I check what happens when writing to
the DB while reading (or even concurrent writes - which definitely no
longer is a safe operation mode for sqlite on a shared network volume <-
if you end up in this category, get a postgres server).
Maybe we need to rethink the default mode of opening gpkg's
and if anyone can provide ground truth on the untested operation modes
mentioned before, please share the results here.
Bests, Matthias
On 10/18/19 8:17 AM, Chavoux Luyt wrote:
Hi,
Just my two cents... this is IMHO exactly where postGIS will shine.
Using PostgreSQL as backend will avoid any of these issues (i.e.
prevent data corruption). For my personal projects I have never
bothered with it, so I cannot say how easy it is to set up, but once
it is up and running PostgreSQL is one of the most reliable database
servers out there.
Cheers,
Chavoux
On Thu, 17 Oct 2019, 21:01 , ---------- Forwarded message ----------
From: Francesco Pelullo <f.pelu...@gmail.com
<mailto:f.pelu...@gmail.com>>
To: Patrick Dunford <enzedrailm...@gmail.com
<mailto:enzedrailm...@gmail.com>>
Cc: qgis-user@lists.osgeo.org <mailto:qgis-user@lists.osgeo.org>
Bcc:
Date: Thu, 17 Oct 2019 13:09:43 +0200
Subject: Re: [Qgis-user] GeoPackage deadlocks (Andrea Peri)
Il gio 17 ott 2019, 12:54 Patrick Dunford <enzedrailm...@gmail.com
<mailto:enzedrailm...@gmail.com>> ha scritto:
It's not a network issue and neither is it a Windows issue. Two
processes accessing geopackage on a local computer can run
into the same
issue. SQlite is designed for a single user. It is very
reliable when
used as
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