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https://issues.apache.org/jira/browse/HIVE-1940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12989494#comment-12989494
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Anja Gruenheid commented on HIVE-1940:
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As first step, I would like to take a closer look at collecting meta data on
the column level. In issue HIVE-33, five different statistics are described (#
distinct values, # null values, 3 min values, 3 max values, avg size of column)
that have been proposed as column meta data. As reference, I would take the
implementation of the table/partition meta data collection.
As far as I can tell, deriving histograms is a little bit more complex than
obtaining column information, which is why I want to start out with that.
Is there an up-to-date MetaStore DDL script or an E/R model?
> Query Optimization Using Column Metadata and Histograms
> -------------------------------------------------------
>
> Key: HIVE-1940
> URL: https://issues.apache.org/jira/browse/HIVE-1940
> Project: Hive
> Issue Type: New Feature
> Components: Metastore, Query Processor
> Reporter: Anja Gruenheid
>
> The current basis for cost-based query optimization in Hive is information
> gathered on tables and partitions. To make further improvements in query
> optimization possible, the next step is to develop and implement
> possibilities to gather information on columns as discussed in issue HIVE-33.
> After that, an implementation of histograms is a possible option to use and
> collect run-time statistics. Next to the actual implementation of these
> features, it is also necessary to develop a consistent storage model for the
> MetaStore.
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