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<p>Hi Mike,</p>
<p>the problem is likely two folds:</p>
<p>- "gdal vector partition" doesn't write the "_metadata" file that
contains the schema and the path to the actual .parquet files</p>
<p>- but even if it did, I cannot manage to convince
libarrow/libparquet to not probe all files. Not sure if I'm
missing something in the API or if that's a fundamental limitation
of the library. I've filed
<a class="moz-txt-link-freetext" href="https://github.com/apache/arrow/issues/48671">https://github.com/apache/arrow/issues/48671</a> about that. I've
considered implementing a workaround on GDAL side but I couldn't
come with anything.</p>
<p>Your best workaround is to directly access <span
style="white-space: pre-wrap"> "/vsis3/bucket/overture/20251217/overture-buildings/country=US" </span><br>
</p>
<p>Even</p>
<div class="moz-cite-prefix">Le 28/12/2025 à 13:26, Michael Smith
via gdal-dev a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:78AB845E-CBE8-4E82-97AD-7BF8166C5F48@gmail.com">
<pre wrap="" class="moz-quote-pre">I know that gdal can write parquet data with hive partitioning using gdal vector partition, but after doing so, can gdal do the partition elimination on reading when a where/attribute is specified on the partition key?
I was trying to do a pipeline with:
gdal vector pipeline ! read "/vsis3/bucket/overture/20251217/overture-buildings/” ! filter --bbox -117.486117584442,33.9156194185775,-117.333055544584,33.9745995301481 --where "country='US'" ! write -f parquet /tmp/test1.parquet --progress --overwrite
but in CPL_DEBUG I see it scanning all the partitions rather than just querying the country=US partition.
S3: Downloading 0-1605631 (<a class="moz-txt-link-freetext" href="https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAI/data_0.parquet">https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAI/data_0.parquet</a>)...
S3: Got response_code=206
S3: Downloading 0-16383999 (<a class="moz-txt-link-freetext" href="https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_2.parquet">https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_2.parquet</a>)...
S3: Got response_code=206
S3: Downloading 0-16383999 (<a class="moz-txt-link-freetext" href="https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_3.parquet">https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_3.parquet</a>)...
S3: Got response_code=206
S3: Downloading 16384000-32767999 (<a class="moz-txt-link-freetext" href="https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_2.parquet">https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_2.parquet</a>)...
S3: Got response_code=206
S3: Downloading 16384000-29741378 (<a class="moz-txt-link-freetext" href="https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_3.parquet">https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_3.parquet</a>)...
....
</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-freetext" href="http://www.spatialys.com">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
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