In many real-world cases, when interacting with hive catalog through Spark SQL, users may just share the `hive-site.xml` for their hive jobs and make a copy to `SPARK_HOME`/conf w/o modification. In Spark, when we generate Hadoop configurations, we will use `spark.buffer.size(65536)` to reset `io.file.buffer.size(4096)`. But when we load the hive-site.xml, we may ignore this behavior and reset `io.file.buffer.size` again according to `hive-site.xml`.
1. The configuration priority for setting Hadoop and Hive config here is not right, while literally, the order should be `spark > spark.hive > spark.hadoop > hive > hadoop`
2. This breaks `spark.buffer.size` congfig's behavior for tuning the IO performance w/ HDFS if there is an existing `io.file.buffer.size` in hive-site.xml