Several parameters of Hive about merge

Hive. merge. mapfiles (defaulttrue): this parameter is used to control whether the file output of the mergeMAP-ONLY Job is used (if DP is supported in Hive, and

Hive. merge. mapfiles (defaulttrue): this parameter is used to control whether the file output of the merge MAP-ONLY Job is used (if DP is supported in Hive, and

Analyze the three obfuscated parameters of Hive about merge:

Hive. mergejob. maponly

Hive. merge. mapfiles

Hive. merge. mapredfiles

The three parameters are the method in which merge outputs the file, and the method in which merge. Does it sound like J?

Hive. merge. mapfiles (defaulttrue): this parameter is used to control whether the file output of the merge MAP-ONLY Job is used (if DP is supported in Hive and the table containing the DP column is involved, if Hadoop does not support CombineInputFormat, that is, version pre-0.20, then this parameter and the next parameter are invalid, that is, both false)

Hive. merge. mapredfiles (defaultfalse): this parameter is used to control the file output of the merge MAP-REDUCE Job.

Hive. mergejob. maponly (defaulttrue): this parameter is used to control merge in the form of MAP-ONLY (a prerequisite is that Hadoop supports CombineInputFormat ,, even if this parameter is set to true before 0.20, it will not take effect) or perform merge in the form of MAP-REDUCE. but there is an unfixed Bug about this parameter (https://issues.apache.org/jira/browse/HIVE-2869) So the default value is true

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Related reading:

Hadoop cluster-based Hive Installation

Differences between Hive internal tables and external tables

Hadoop + Hive + Map + reduce cluster installation and deployment

Install in Hive local standalone Mode

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