There is a batch put support in the HRegion level. When the put(List<Put>) happens from client, Puts corresponding to one region might get grouped together and handled as a batch.[Depending on the availability of rowlocks.. code in HRegion#doMiniBatchPut] For this batch there will be single write and sync into the HLog file.
A similar kind of delete operation, I am not able to see in HRegion. The HTable#delete(List<Delete>) groups the Deletes for the same RS and make one n/w call only. But within the RS, there will be N number of delete calls on the region one by one. This will include N number of HLog write and sync. If this also can be grouped can we get better performance for the multi row delete. Is there any problem in doing this batch delete? I am not sure any JIRA is already present for this.
Note : Hregion#mutateRowsWithLock().. we do batch operations of Puts and Deletes(also)