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From Ted Yu <yuzhih...@gmail.com>
Subject Re: When compactions become major ones
Date Tue, 05 Jan 2016 15:04:25 GMT
For #1, when all store files are selected for compaction, the compaction
becomes major

see 'Determine the Optimal Number of Pre-Split Regions' under:
http://hbase.apache.org/book.html#disable.splitting

See also http://hbase.apache.org/book.html#managed.compactions

Cheers

On Tue, Jan 5, 2016 at 6:52 AM, Mehdi Ben Haj Abbes <mehdi.abbes@gmail.com>
wrote:

> Hi folks,
>
> I'm using hbase 0.98. I have heavy writes workload. I'm writing to one
> table with one CF compressed with GZ. My table is pre splitted to 27
> regions. As I start writing to this table I start seeing HFiles of the size
> of 2-4 MB across the regions. I have the default hbase configuration for
> compaction properties. The compactions start as soon as I start writing to
> HBase but many of these compaction are major ones. I can see this through
> HBase master UI on the table details view. So I wanted to understand when a
> compaction becomes major.
>
> Another question, If I'm not wrong we have a memstore per region, so when a
> memstore is flushed I will have a HFile with 128MB but I only see files
> with 42MB (without compression and 2.5MB when compressed with GZ).
>
> Any explanation ?
>
> Thanks in advance.
> --
> Mehdi BEN HAJ ABBES
>

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