For #2, see the following in CompactSplitThread - there is a config
parameter for merge threads as well:
// Configuration key for the large compaction threads.
public final static String LARGE_COMPACTION_THREADS =
"hbase.regionserver.thread.compaction.large";
public final static int LARGE_COMPACTION_THREADS_DEFAULT = 1;
// Configuration key for the small compaction threads.
public final static String SMALL_COMPACTION_THREADS =
"hbase.regionserver.thread.compaction.small";
public final static int SMALL_COMPACTION_THREADS_DEFAULT = 1;
// Configuration key for split threads
public final static String SPLIT_THREADS =
"hbase.regionserver.thread.split";
public final static int SPLIT_THREADS_DEFAULT = 1;
On Thu, May 5, 2016 at 6:55 PM, Ted Yu <[email protected]> wrote:
> For #3, we already have the following in 1.1 release:
>
> HBASE-10201 Port 'Make flush decisions per column family' to trunk
>
> On Thu, May 5, 2016 at 6:36 PM, Shushant Arora <[email protected]>
> wrote:
>
>> 1.Why is it better to have single file per region than multiple files for
>> read performance. Why can't multile threads read multiple file and give
>> better performance?
>>
>> 2Does hbase regionserver has single thread for compactions and split for
>> all regions its holding? Why can't single thread per regions will work
>> better than sequential compactions/split for all regions in a
>> regionserver.
>>
>> 3.Why hbase flush and compact all memstores of all the families of a table
>> at same time irrespective of their size when even one memstore reaches
>> threshold.
>>
>> Thanks
>> Shushant
>>
>
>
