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MRS-operation-guide-lts/doc/component-operation-guide/source/using_hive/customizing_row_separators.rst
proposalbot 3ccfbdc0f0 Changes to mrs_operation-guide from docs/doc-exports#475 (MRS component operatio 
Reviewed-by: Kacur, Michal <michal.kacur@t-systems.com>
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2022-12-09 14:50:38 +00:00

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Customizing Row Separators

Scenario

In most cases, a carriage return character is used as the row delimiter in Hive tables stored in text files, that is, the carriage return character is used as the terminator of a row during queries. However, some data files are delimited by special characters, and not a carriage return character.

MRS Hive allows you to use different characters or character combinations to delimit rows of Hive text data. When creating a table, set inputformat to SpecifiedDelimiterInputFormat, and set the following parameter before search each time. Then the table data is queried by the specified delimiter.

set hive.textinput.record.delimiter='';

Note

  • The Hue component of the current version does not support the configuration of multiple separators when files are imported to a Hive table.
  • This section applies to MRS 3.x or later.

Procedure

  1. Specify inputFormat and outputFormat when creating a table.

    CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name [(col_name data_type [COMMENT col_comment], ...)] [ROW FORMAT row_format] STORED AS inputformat 'org.apache.hadoop.hive.contrib.fileformat.SpecifiedDelimiterInputFormat' outputformat 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'

  2. Specify the delimiter before search.

    set hive.textinput.record.delimiter='!@!'

    Hive will use '!@!' as the row delimiter.