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https://issues.apache.org/jira/browse/DRILL-680?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14005334#comment-14005334
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Aditya Kishore commented on DRILL-680:
--------------------------------------
With this patch, HBase storage engine will publish the scheme of an HBase table
in the following format.
Column 0: \{"ORDINAL_POSITION":"0": "COLUMN_NAME": "row_key", "DATA_TYPE":
"VARBINARY", "IS_NULLABLE":"No"\}.
And for each column family (in the lexicographically sorted order)
Column 1: \{"ORDINAL_POSITION":"1": "COLUMN_NAME": "<cf_1_name>", "DATA_TYPE":
"MAP", "IS_NULLABLE":"No"\}.
...
Column n: \{"ORDINAL_POSITION":"<n>": "COLUMN_NAME": "<cf_n_name>",
"DATA_TYPE": "MAP", "IS_NULLABLE":"No"\}.
Example:
{noformat}
0: jdbc:drill:zk=local> SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE
TABLE_NAME='students';
+---------------+--------------+------------+-------------+------------------+-------------+------------+--------------------------+-------------------------+---------------+-------------------+
| TABLE_CATALOG | TABLE_SCHEMA | TABLE_NAME | COLUMN_NAME | ORDINAL_POSITION |
IS_NULLABLE | DATA_TYPE | CHARACTER_MAXIMUM_LENGTH | NUMERIC_PRECISION_RADIX |
NUMERIC_SCALE | NUMERIC_PRECISION |
+---------------+--------------+------------+-------------+------------------+-------------+------------+--------------------------+-------------------------+---------------+-------------------+
| DRILL | hbase | students | row_key | 0 |
NO | VARBINARY | -1 | -1 |
-2147483648 | -1 |
| DRILL | hbase | students | cf1 | 1 |
NO | MAP | -1 | -1 |
-1 | -1 |
| DRILL | hbase | students | cf2 | 2 |
NO | MAP | -1 | -1 |
-1 | -1 |
| DRILL | hbase | students | cf3 | 3 |
NO | MAP | -1 | -1 |
-1 | -1 |
+---------------+--------------+------------+-------------+------------------+-------------+------------+--------------------------+-------------------------+---------------+-------------------+
4 rows selected (0.552 seconds)
{noformat}
> INFORMATION_SCHEMA.COLUMNS does not display hbase column familes
> ----------------------------------------------------------------
>
> Key: DRILL-680
> URL: https://issues.apache.org/jira/browse/DRILL-680
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Rahul Challapalli
> Assignee: Aditya Kishore
> Attachments:
> DRILL-680-INFORMATION_SCHEMA.COLUMNS-does-not-displa.patch
>
>
> Hbase Column families are not being shown in INFORMATION_SCHEMA.COLUMNS table
> hbase> create 'students', 'cf1', 'cf2', 'cf3'
> drill> SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='hbase'
> AND TABLE_NAME='students';
> The above query should return one row for each column family and probably one
> more column for the hbase rowkey.
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