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https://issues.apache.org/jira/browse/DRILL-7293?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16872907#comment-16872907
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ASF GitHub Bot commented on DRILL-7293:
---------------------------------------
paul-rogers commented on issue #1807: DRILL-7293: Convert the regex ("log")
plugin to use EVF
URL: https://github.com/apache/drill/pull/1807#issuecomment-505714454
@arina-ielchiieva, I was able to get the plugin to work for this query:
```
SELECT * FROM table(dfs.tf.table1(
type => 'logRegex',
regex => '(\\d\\d\\d\\d)-(\\d\\d)-(\\d\\d) .*',
maxErrors => 10))
```
To do this, I had to fix some of the issues described in DRILL-7298. In
particular, DRILL-6672 notes that table functions are not able to call
{{setFoo()}} methods as Jackson can, so table functions only work if the format
plugin config fields are {{public}}. The were not public for the log format
plugin, so I changed them to {{public}} to get the above query to work.
If we look at the code in
[`FormatPluginOptionsDescriptor.createConfigForTable()`](https://github.com/apache/drill/blob/master/exec/java-exec/src/main/java/org/apache/drill/exec/store/dfs/FormatPluginOptionsDescriptor.java#L123),
we'll see that there is nothing that would handle the `values` syntax
suggested in your note. The only supported types are Java primitives.
When I tried this query:
```
SELECT * FROM table(dfs.tf.noGroups(
type => 'logRegex',
regex => '(\\d\\d\\d\\d)-(\\d\\d)-(\\d\\d) .*',
`schema`=>values('month', 'VARCHAR')))
```
I got this result:
```
PARSE ERROR: Encountered "values" at line 1, column 115.
SQL Query: SELECT * FROM table(dfs.tf.noGroups(type => 'logRegex', regex =>
'(\\d\\d\\d\\d)-(\\d\\d)-(\\d\\d) .*', `schema`=>values('month', 'VARCHAR')))
^
```
So, looks like the {{values}} trick does not work. Even if it did, the code
to produce the values argument would use some kind of Java collection which
would not match the {{List<LogFormatField>}} of the {{schema}} field.
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> Convert the regex ("log") plugin to use EVF
> -------------------------------------------
>
> Key: DRILL-7293
> URL: https://issues.apache.org/jira/browse/DRILL-7293
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.16.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Major
> Fix For: 1.17.0
>
>
> The "log" plugin (which uses a regex to define the row format) is the subject
> of Chapter 12 of the Learning Apache Drill book (though the version in the
> book is simpler than the one in the master branch.)
> The recently-completed "Enhanced Vector Framework" (EVF, AKA the "row set
> framework") gives Drill control over the size of batches created by readers,
> and allows readers to use the recently-added provided schema mechanism.
> We wish to use the log reader as an example for how to convert a Drill format
> plugin to use the EVF so that other developers can convert their own plugins.
> This PR provides the first set of log plugin changes to enable us to publish
> a tutorial on the EVF.
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