Well, I believe Hive use it to combine/merge like this (via https://issues.apache.org/jira/browse/HIVE-74) -
```
hive.input.format (org.apache.hadoop.hive.ql.io.CombineHiveInputFormat (default, if empty), or org.apache.hadoop.hive.ql.io.HiveInputFormat)
mapred.min.split.size.per.node (the minimum bytes of data to create a node-local partition, otherwise the data will combine to rack level. default:0)
mapred.min.split.size.per.rack (the minimum bytes of data to create a rack-local partition, otherwise the data will combine to global level. default:0)
mapred.max.split.size (the max size of each split, will be exceeded because we stop accumulating *after* reaching it, instead of before)
```