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DeterminePartitionsJob: Fix docs

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Gian Merlino 2013-02-13 10:16:03 -08:00 committed by xvrl
parent ee193f0ca7
commit e3822f6ca7
1 changed files with 4 additions and 1 deletions
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5
indexer/src/main/java/com/metamx/druid/indexer/DeterminePartitionsJob.java
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@ -79,13 +79,16 @@ import java.util.Set;
/**
* Determines appropriate ShardSpecs for a job by determining whether or not partitioning is necessary, and if so,
* choosing the highest cardinality dimension that satisfies the criteria:
* choosing the best dimension that satisfies the criteria:
*
* <ul>
* <li>Must have exactly one value per row.</li>
* <li>Must not generate oversized partitions. A dimension with N rows having the same value will necessarily
* put all those rows in the same partition, and that partition may be much larger than the target size.</li>
* </ul>
*
* "Best" means a very high cardinality dimension, or, if none exist, the dimension that minimizes segment size
* variance.
*/
public class DeterminePartitionsJob implements Jobby
{