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From Jean-Daniel Cryans <jdcry...@apache.org>
Subject Re: How to prevent major compaction when doing bulk load provisioning?
Date Thu, 21 Mar 2013 18:03:44 GMT
You are likely just hitting the threshold for a minor compaction and
by picking up all the files (I'm making a guess that it does) it gets
upgraded to a major compaction. The threshold is 3 by default.

So after loading 3 files you should get a compaction per region, then
every other 2 loading you will trigger another per region.

It seems to me that it would be better if you were able to do a single
load for all your files.


On Thu, Mar 21, 2013 at 6:29 AM, Nicolas Seyvet
<nicolas.seyvet@gmail.com> wrote:
> Hi,
> We are using code similar to
> https://github.com/jrkinley/hbase-bulk-import-example/ in order to
> benchmark our HBase cluster.  We are running a CDH4 installation, and HBase
> is version 0.92.1-cdh4.1.1..  The cluster is composed of 12 slaves and 1
> master and 1 secondary master.
> During the bulk load insert, roughly within 3 hours after the start
> (~200Gb), we notice a large drop in performance in the insert rate. At the
> same time, there is a spike in IO and CPU usage.  Connecting to a Region
> Server (RS), the Monitored Task section shows that a compaction is started.
> I have set hbase.hregion.max.filesize to 107374182400 (100Gb), and disable
> automatic major compaction hbase.hregion.majorcompactionis set to 0.
> What we are doing is that we have 1000 files of synthetic data (csv), where
> each row in a file is one row to insert into HBase, each file contains 600K
> rows (or 600K events).  Our loader works in the following way:
> 1. Look for a file
> 2. When a file is found, prepare a job for that file
> 3. Launch job
> 4. Wait for completion
> 5. Compute insert rate (nb of rows /time)
> 6. Repeat from 1 until there are no more files.
> What I understand of the bulk load M/R job is that it produces one HFile
> for each Region.
> Questions:
> - How is HStoreFileSize calclulated?
> - What do HStoreFileSize, storeFileSize and hbase.hregion.max.filesize have
> in common?
> - Can the number of HFiles trigger a major compaction?
> Thx for help.  I hope my questions make sense.
> /Nicolas

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