[jira] [Commented] (DRILL-6096) Provide mechanisms to specify field delimiters and quoted text for TextRecordWriter

["benj (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DRILL-6096?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17038357#comment-17038357 ] 

benj commented on DRILL-6096:
-----------------------------

Just trying to use this new functionality. Some points (tested in 1.17 and last 1.18 @ 2020-02-17) :
 * Should at least add _"write_text"_ in description of allowed values for option _store.format_
 * Why _write_text_ doesn't appears in default storage configuration ?
 * Try to create write_text or equivalent in storage configuration but use of _"fieldDelimiter"_ produce _"Please retry: Error (invalid JSON mapping)"_ - need a new ticket ?

> Provide mechanisms to specify field delimiters and quoted text for TextRecordWriter
> -----------------------------------------------------------------------------------
>
>                 Key: DRILL-6096
>                 URL: https://issues.apache.org/jira/browse/DRILL-6096
>             Project: Apache Drill
>          Issue Type: Improvement
>          Components: Storage - Text & CSV
>    Affects Versions: 1.12.0
>            Reporter: Kunal Khatua
>            Assignee: Arina Ielchiieva
>            Priority: Major
>              Labels: doc-impacting, ready-to-commit
>             Fix For: 1.17.0
>
>
> Currently, there is no way for a user to specify the field delimiter for the writing records as a text output. Further more, if the fields contain the delimiter, we have no mechanism of specifying quotes.
> By default, quotes should be used to enclose non-numeric fields being written.
> *Description of the implemented changes:*
> 2 options are added to control text writer output:
> {{store.text.writer.add_header}} - indicates if header should be added in created text file. Default is true.
> {{store.text.writer.force_quotes}} - indicates if all value should be quoted. Default is false. It means only values that contain special characters (line / field separators) will be quoted.
> Line / field separators, quote / escape characters can be configured using text format configuration using Web UI. User can create special format only for writing data and then use it when creating files. Though such format can be always used to read back written data.
> {noformat}
>   "formats": {
>     "write_text": {
>       "type": "text",
>       "extensions": [
>         "txt"
>       ],
>       "lineDelimiter": "\n",
>       "fieldDelimiter": "!",
>       "quote": "^",
>       "escape": "^",
>     }
>    },
> ...
> {noformat}
> Next set specified format and create text file:
> {noformat}
> alter session set `store.format` = 'write_text';
> create table dfs.tmp.t as select 1 as id from (values(1));
> {noformat}
> Notes:
> 1. To write data univocity-parsers are used, they limit line separator length to not more than 2 characters, though Drill allows setting more 2 chars as line separator since Drill can read data splitting by line separator of any length, during data write exception will be thrown.
> 2. {{extractHeader}} in text format configuration does not affect if header will be written to text file, only {{store.text.writer.add_header}} controls this action. {{extractHeader}} is used only when reading the data.



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