Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Plain View
HBase, mail # user - HBase Thrift inserts bottlenecked somewhere -- but where?


+
Dan Crosta 2013-03-01, 12:17
+
Asaf Mesika 2013-03-01, 14:13
+
Dan Crosta 2013-03-01, 14:17
+
Jean-Daniel Cryans 2013-03-01, 17:33
+
Varun Sharma 2013-03-01, 18:46
+
Varun Sharma 2013-03-01, 18:46
+
Dan Crosta 2013-03-01, 18:49
+
Ted Yu 2013-03-01, 18:52
+
Varun Sharma 2013-03-01, 19:01
+
Ted Yu 2013-03-02, 03:53
+
Dan Crosta 2013-03-02, 17:15
+
lars hofhansl 2013-03-02, 03:42
+
Dan Crosta 2013-03-02, 17:12
+
lars hofhansl 2013-03-02, 17:38
Copy link to this message
-
Re: HBase Thrift inserts bottlenecked somewhere -- but where?
Dan Crosta 2013-03-02, 18:47
On Mar 2, 2013, at 12:38 PM, lars hofhansl wrote:
> "That's only true from the HDFS perspective, right? Any given region is
> "owned" by 1 of the 6 regionservers at any given time, and writes are
> buffered to memory before being persisted to HDFS, right?"
>
> Only if you disabled the WAL, otherwise each change is written to the WAL first, and then committed to the memstore.
> So in the sense it's even worse. Each edit is written twice to the FS, replicated 3 times, and all that only 6 data nodes.

Are these writes synchronized somehow? Could there be a locking problem somewhere that wouldn't show up as utilization of disk or cpu?

What is the upshot of disabling WAL -- I assume it means that if a RegionServer crashes, you lose any writes that it has in memory but not committed to HFiles?
> 20k writes does seem a bit low.

I adjusted dfs.datanode.handler.count from 3 to 10 and now we're up to about 22-23k writes per second, but still no apparent contention for any of the basic system resources.

Any other suggestions on things to try?

Thanks,
- Dan
+
Asaf Mesika 2013-03-02, 19:56
+
Ted Yu 2013-03-02, 20:02
+
lars hofhansl 2013-03-02, 20:50
+
lars hofhansl 2013-03-02, 20:50
+
Dan Crosta 2013-03-02, 22:29
+
Varun Sharma 2013-03-03, 11:08
+
Dan Crosta 2013-03-03, 13:53
+
lars hofhansl 2013-03-02, 20:56
+
Andrew Purtell 2013-03-05, 07:04