<div dir="ltr">> <br style="color:rgb(0,0,0);font-size:12.8px"><span style="color:rgb(0,0,0);font-size:12.8px">A common workflow that leads to this situation is when working on shapefiles and then using them in a processing algorithm that involves an external process. The processing situation could be avoided (detect if potentially dangerous operations like a delete have been performed since the last repack and if yes repack or write it to a new file), but there were also other situations where people just have been working on the same file in different GIS applications side-by-side.</span><div><span style="color:rgb(0,0,0);font-size:12.8px"><br></span></div><div><span style="color:rgb(0,0,0);font-size:12.8px"><br></span></div><div><font color="#000000"><span style="font-size:12.8px">This raises the question. Should we support that? A lot of file types are just not meant to be opened by many applications at the same, e.g MapInfo wants a full exclusive read/write lock on tab files. My gut has always been if it's file based you shouldn't be using it in other applications at the same time. </span></font></div><div><font color="#000000"><span style="font-size:12.8px"><br></span></font></div><div><font color="#000000"><span style="font-size:12.8px">- Nathan</span></font></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jul 5, 2017 at 6:47 AM, Matthias Kuhn <span dir="ltr"><<a href="mailto:matthias@opengis.ch" target="_blank">matthias@opengis.ch</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"><span class="">
<p>On 7/4/17 6:46 PM, Even Rouault wrote:
</p>
<blockquote type="cite">
<p style="margin-top:0px;margin-bottom:0px;margin-left:0px;margin-right:0px;text-indent:0px">Another solution would be to defere the compaction only at layer closing (that's actually the new behaviour of the OGR Shapefile driver in recent GDAL versions to force a repack at closing). I'm not sure why QGIS currently repacks it every time ?</p>
</blockquote>
<br></span>
IIRC, in situations where the layer has not been closed and was
still used by other software at the same time, issues arose.<br>
<br>
In particular features flagged as deleted by OGR (and no longer
reported as existing features by OGR) were still detected as
existing features by other applications. Often, this was surprising
in situations when people were working on shapefiles, deleted some
features and then used this file in a different application while it
was still open in QGIS.<br>
<br>
A common workflow that leads to this situation is when working on
shapefiles and then using them in a processing algorithm that
involves an external process. The processing situation could be
avoided (detect if potentially dangerous operations like a delete
have been performed since the last repack and if yes repack or write
it to a new file), but there were also other situations where people
just have been working on the same file in different GIS
applications side-by-side.<br>
<br>
From the lack of reported issues regarding this in the last two
years (compared to the time before) I suspect the current approach
suits many use-cases quite well. At the same time, I am very
surprised that this is the very first issue that I am aware of which
is related to 7d7cdcd3.<span class="HOEnZb"><font color="#888888"><br>
<br>
Matthias</font></span><span class=""><br>
<br>
<blockquote type="cite">
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</blockquote>
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