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<p class="MsoNormal">Hi Even,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks for the quick response! The source dataset is a LZW cog with RGBA, and I confirmed (I think) that the issue was the mask layer by playing with the switches I used to generate the LZW cog – I didn’t even have to do a JPEG COG. I can
cause the same, or very similar behavior, by changing from:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-b 1 -b 2 -b 3 -b 4 <o:p></o:p></p>
<p class="MsoNormal">to:<o:p></o:p></p>
<p class="MsoNormal">-b 1 -b 2 -b 3 -mask 4 <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">with GDAL_TIFF_INTERNAL_MASK YES. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">With the -b 4 switch (or omitting all -b and -mask switches), I get LZW cogs in 2 minutes. With -mask 4 I get hung up at 20% with directory thrashing messages in debug for at least 30 minutes, and I’m guessing I’ll get the same behavior
at the “done” message if I care to wait.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Below are the two configurations that show such a difference in performance for me. I didn’t play around with CACHEMAX or MAX_DATASET_POOL_SIZE, was trying to keep it simple.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2 minute TIFFs:<o:p></o:p></p>
<p class="MsoNormal">gdal_translate <infile> <outfile> -b 1 -b 2 -b 3 -b 4 -of COG -co COMPRESS=LZW -co PREDICTOR=2 -co NUM_THREADS=ALL_CPUS -co RESAMPLING=AVERAGE –config GDAL_TIFF_INTERNAL_MASK YES –config GDAL_TIF_OVR_BLOCKSIZE 128<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">A couple orders of magnitude longer:<o:p></o:p></p>
<p class="MsoNormal">gdal_translate <infile> <outfile> -b 1 -b 2 -b 3 -mask 4 -of COG -co COMPRESS=LZW -co PREDICTOR=2 -co NUM_THREADS=ALL_CPUS -co RESAMPLING=AVERAGE –config GDAL_TIFF_INTERNAL_MASK YES –config GDAL_TIF_OVR_BLOCKSIZE 128<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Even Rouault <even.rouault@spatialys.com> <br>
<b>Sent:</b> Wednesday, April 15, 2020 4:38 AM<br>
<b>To:</b> gdal-dev@lists.osgeo.org<br>
<b>Cc:</b> Ritchie, Andrew C <aritchie@usgs.gov><br>
<b>Subject:</b> [EXTERNAL] Re: [gdal-dev] gdal_translate (3.1.0dev) "never" finishes on large jpeg cogs... REALLLLLY long time to unload.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:9.0pt;font-family:"Courier New"">Andrew,<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New"">Has your source raster an alpha band ? That could explain the difference since it isn't possible to directly create a YCbCrA JPEG compressed file, but internally a mask band must be created. However I
wouldn't anticipate such a huge difference in performance between compression schemes. I would suggest not setting GDAL_CACHEMAX at all and letting it at its 5% default (increasing it is not always a good idea), in case it would be a performance issue at de-allocating
cached blocks. <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-paragraph-type:empty;-qt-block-indent:0">
<span style="font-size:9.0pt;font-family:"Courier New"">Even<o:p></o:p></span></p>
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<span style="font-size:9.0pt;font-family:"Courier New"">-- <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New"">Spatialys - Geospatial professional services<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt;-qt-block-indent:0;-qt-user-state:0"><span style="font-size:9.0pt;font-family:"Courier New""><a href="http://www.spatialys.com">http://www.spatialys.com</a><o:p></o:p></span></p>
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