在 Apache Drill 中 JDBC 扫描时，列名未传递给 PostgreSQL

Question

在尝试运行 SQL 查询 PostgreSQL 时，而不是 table 中的列名引用它，它向下推送 * 到数据库。

select
  m.m_id,
  cnt_c_no
from (
    select
      m_id
    from pg_test_main.test1.table1
    where
      last_date >= '2019-01-01 00:00:00'
  ) as m
left join (
    select
      ci.m_id,
      count(ci.c_no) as cnt_c_no
    from (
        select
          m_id,
          c_no
        from pg_test.public.table2
      ) as ci
    inner join (
        select
          c_no
        from pg_test.public.table3
        where
          is_del = 'F'
      ) as c on ci.c_no = c.c_no
    group by
      ci.m_id
  ) as join1 on m.m_id = join1.m_id;

00-00    Screen
00-01      Project(m_id=[[=12=]], cnt_c_no=[])
00-02        Project(m_id=[[=12=]], cnt_c_no=[])
00-03          HashJoin(condition=[=([=12=], )], joinType=[left], semi-join: =[false])
00-05            Jdbc(sql=[SELECT "m_id" FROM "test1"."table1" WHERE "last_date" >= '2019-01-01 00:00:00' ])
00-04            Project(m_id0=[[=12=]], cnt_c_no=[])
00-06              HashAgg(group=[{0}], cnt_c_no=[COUNT()])
00-07                Project(m_id=[[=12=]], c_no=[])
00-08                  HashJoin(condition=[=(, )], joinType=[inner], semi-join: =[false])
00-10                    Project(m_id=[], c_no=[])
00-12                      Jdbc(sql=[SELECT * FROM "public"."table2" ])
00-09                    Project(c_no0=[[=12=]])
00-11                      Project(c_no=[[=12=]])
00-13                        SelectionVectorRemover
00-14                          Filter(condition=[=(, 'F')])
00-15                            Jdbc(sql=[SELECT * FROM "public"."table3" ])

如您所见，Jdbc table1 扫描使用的是列名称。

但是，Jdbc 扫描 table2 和 table3 没有使用列名。它将 * 推送到数据库。

如何控制 jdbc 扫描以便它可以下推列名称？

Apache Drill 版本为 1.16.0（嵌入式模式）

Answer 1

我试图在 Drill 1.17 和 Drill 1.15 上用 MySQL 重现它，但是对于查询，类似于您指定的查询，所有查询都被推送到 JDBC 存储中:

SELECT m.person_id,
       cnt_c_no
FROM
  (SELECT person_id
   FROM mysql.`drill_mysql_test1`.person1
   WHERE date_field >= '2019-01-01 00:00:00') AS m
LEFT JOIN
  (SELECT ci.person_id,
          count(ci.last_name) AS cnt_c_no
   FROM
     (SELECT person_id,
             last_name
      FROM mysql.`drill_mysql_test`.person) AS ci
   INNER JOIN
     (SELECT last_name
      FROM mysql.`drill_mysql_test`.person2
      WHERE boolean_field = 'F' ) AS c ON ci.last_name = c.last_name
   GROUP BY ci.person_id) AS join1 ON m.person_id = join1.person_id

此查询的计划：

00-00    Screen
00-01      Project(person_id=[[=11=]], cnt_c_no=[])
00-02        Jdbc(sql=[SELECT `t0`.`person_id`, `t5`.`cnt_c_no` FROM (SELECT `person_id` FROM `drill_mysql_test1`.`person1` WHERE `date_field` >= '2019-01-01 00:00:00') AS `t0` LEFT JOIN (SELECT `t1`.`person_id`, COUNT(`t1`.`last_name`) AS `cnt_c_no` FROM (SELECT `person_id`, `last_name` FROM `drill_mysql_test`.`person`) AS `t1` INNER JOIN (SELECT `last_name` FROM `drill_mysql_test`.`person2` WHERE `boolean_field` = 'F') AS `t3` ON `t1`.`last_name` = `t3`.`last_name` GROUP BY `t1`.`person_id`) AS `t5` ON `t0`.`person_id` = `t5`.`person_id` ])

能否请您为 Postgres 表提供 CTAS，因此我将尝试使用特定数据类型再次重现它。另外，如果可能，请检查此问题是否仍然在 Drill 1.17 上重现。

更新： 在此答案下评论有助于发现此问题是由以下问题引起的：https://issues.apache.org/jira/browse/DRILL-7340 并将在 Drill 1.18.0 中解决。

在 Apache Drill 中 JDBC 扫描时，列名未传递给 PostgreSQL

Column name is not passed to PostgreSQL on JDBC Scan in Apache Drill

jdbc

apache-drill