Hi Mike,

the problem is likely two folds:

- "gdal vector partition" doesn't write the "_metadata" file that contains the schema and the path to the actual .parquet files

- 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 https://github.com/apache/arrow/issues/48671 about that.  I've considered implementing a workaround on GDAL side but I couldn't come with anything.

Your best workaround is to directly access "/vsis3/bucket/overture/20251217/overture-buildings/country=US"

Even

Le 28/12/2025 à 13:26, Michael Smith via gdal-dev a écrit :
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 
(https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAI/data_0.parquet)...
S3: Got response_code=206
S3: Downloading 0-16383999 
(https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_2.parquet)...
S3: Got response_code=206
S3: Downloading 0-16383999 
(https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_3.parquet)...
S3: Got response_code=206
S3: Downloading 16384000-32767999 
(https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_2.parquet)...
S3: Got response_code=206
S3: Downloading 16384000-29741378 
(https://bucket.s3.us-east-1.amazonaws.com/overture/20251217/overture-buildings/country%3DAL/data_3.parquet)...
....



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