wForget commented on code in PR #4931:
URL: https://github.com/apache/datafusion-comet/pull/4931#discussion_r3583902439


##########
docs/source/user-guide/latest/tuning.md:
##########
@@ -186,6 +186,14 @@ By default, Spark compresses shuffle files using LZ4 
compression. Comet override
 Compression can be disabled by setting `spark.shuffle.compress=false`, which 
may result in faster shuffle times in
 certain environments, such as single-node setups with fast NVMe drives, at the 
expense of increased disk space usage.
 
+### Native scans
+
+For native scans it is better to check `spark.sql.files.maxPartitionBytes` 
which is `128M` by default and
+set it to `spark.sql.files.maxPartitionBytes: 64M`. The difference comes from 
how Apache DataFusion and Spark determine the Parquet row group boundaries.

Review Comment:
   Does this mean we should recommend setting 
`spark.sql.files.maxPartitionBytes` to half of `parquet.block.size`?
   



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