[GitHub] [spark] jeff303 opened a new pull request #26027: [SPARK-24540][SQL] Support for multiple delimiter in Spark CSV read

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jeff303 opened a new pull request #26027: [SPARK-24540][SQL] Support for multiple delimiter in Spark CSV read
URL: https://github.com/apache/spark/pull/26027
 
 
   Updating univocity-parsers version to 2.8.3, which adds support for multiple character delimiters
   
   Moving univocity-parsers version to spark-parent pom dependencyManagement section
   
   Adding new utility method to build multi-char delimiter string, which delegates to existing one
   
   Adding tests for multiple character delimited CSV
   
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   ### What changes were proposed in this pull request?
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   Adds support for parsing CSV data using multiple-character delimiters.  Existing logic for converting the input delimiter string to characters was kept and invoked in a loop.  Project dependencies were updated to remove redundant declaration of `univocity-parsers` version, and also to change that version to the latest.
   
   ### Why are the changes needed?
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   It is quite common for people to have delimited data, where the delimiter is not a single character, but rather a sequence of characters.  Currently, it is difficult to handle such data in Spark (typically needs pre-processing).
   
   ### Does this PR introduce any user-facing change?
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   Yes. Specifying the "delimiter" option for the DataFrame read, and providing more than one character, will no longer result in an exception.  Instead, it will be converted as before and passed to the underlying library (Univocity), which has accepted multiple character delimiters since 2.8.0.
   
   ### How was this patch tested?
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   The `CSVSuite` tests were confirmed passing (including new methods), and `sbt` tests for `sql` were executed.

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