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Date: Thu, 22 Nov 2012 09:08:58 +0000 (UTC)
From: =?utf-8?Q?Piotr_Ko=C5=82aczkowski_=28JIRA=29?= <jira@apache.org>
To: commits@cassandra.apache.org
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Subject: [jira] [Created] (CASSANDRA-4983) Improve range wrap-around in
 CFIF: CFIF shouldn't produce input splits of very tiny size
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Piotr Ko=C5=82aczkowski created CASSANDRA-4983:
---------------------------------------------

             Summary: Improve range wrap-around in CFIF: CFIF shouldn't pro=
duce input splits of very tiny size
                 Key: CASSANDRA-4983
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4983
             Project: Cassandra
          Issue Type: Improvement
    Affects Versions: 1.1.6
            Reporter: Piotr Ko=C5=82aczkowski
            Assignee: Piotr Ko=C5=82aczkowski
            Priority: Minor


Currently CFIF splits the wrap-around split into two non-wrap-around splits=
. While it simplifies CFRR implementation, this approach has several minor =
downsides:

 * One of the splits can be extremely small. One of our (picky) customers s=
uspected there must be a bug, because one of his map tasks executed in 1  s=
econd, while all the rest executed in minutes. Also having a very small tas=
k is wasting resources - more resources go to launching the task than doing=
 any real work.

 * The number of map tasks is always one more than the number of (expected =
rows / cassandra.input.split.size). The number of map tasks is always >=3D =
2. This is confusing customers.=20

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