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https://issues.apache.org/jira/browse/DRILL-5183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16070547#comment-16070547
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Rahul Challapalli commented on DRILL-5183:
------------------------------------------
Hmm.....this is clearly a bug we should fix. Have you considered the below
workaround using a view
{code}
0: jdbc:drill:zk=10.10.100.190:5181> create view drill5183 as select d.title,
d.pages, d.authors.`array` authors from dfs.`/drill/testdata/books.parquet` d;
+-------+---------------------------------------------------------------------+
| ok | summary |
+-------+---------------------------------------------------------------------+
| true | View 'drill5183' created successfully in 'dfs.drillTestDir' schema |
+-------+---------------------------------------------------------------------+
1 row selected (0.403 seconds)
0: jdbc:drill:zk=10.10.100.190:5181> select * from drill5183;
+---------------------------------------+--------+------------------------------------------------+
| title | pages | authors
|
+---------------------------------------+--------+------------------------------------------------+
| Physics of Waves | 477 | ["William C. Elmore","Mark
A. Heald"] |
| Foundations of Mathematical Analysis | 428 | ["Richard
Johnsonbaugh","W.E. Pfaffenberger"] |
+---------------------------------------+--------+------------------------------------------------+
2 rows selected (0.33 seconds)
{code}
> Drill doesn't seem to handle array values correctly in Parquet files
> --------------------------------------------------------------------
>
> Key: DRILL-5183
> URL: https://issues.apache.org/jira/browse/DRILL-5183
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Dave Kincaid
> Attachments: books.parquet
>
>
> It looks to me that Drill is not properly converting array values in Parquet
> records. I have created a simple example and will attach a simple Parquet
> file to this issue. If I write Parquet records using the Avro schema
> {code:title=Book.avsc}
> { "type": "record",
> "name": "Book",
> "fields": [
> { "name": "title", "type": "string" },
> { "name": "pages", "type": "int" },
> { "name": "authors", "type": {"type": "array", "items": "string"} }
> ]
> }
> {code}
> I write two records using this schema into the attached Parquet file and then
> simply run {{SELECT * FROM dfs.`books.parquet`}} I get the following result:
> ||title||pages||authors||
> |Physics of Waves|477|{"array":["William C. Elmore","Mark A. Heald"]}|
> |Foundations of Mathematical Analysis|428|{"array":["Richard
> Johnsonbaugh","W.E. Pfaffenberger"]}|
> You can see that the authors column seems to be a nested record with the name
> "array" instead of being a repeated value. If I change the SQL query to
> {{SELECT title,pages,t.authors.`array` FROM
> dfs.`/home/davek/src/drill-parquet-example/resources/books.parquet` t;}} then
> I get:
> ||title||pages||EXPR$2||
> |Physics of Waves|477|["William C. Elmore","Mark A. Heald"]|
> |Foundations of Mathematical Analysis|428|["Richard Johnsonbaugh","W.E.
> Pfaffenberger"]|
> and now that column behaves in Drill as a repeated values column.
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