[HAWQ-1513] "string_agg" function does not support query optimization on partitioned table

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Catalog
• Assignee: Radar Da Lei
• Reporter: lynn
• Created: 08/Aug/17 09:32
• Updated: 10/Nov/17 07:31

Description

The table "t1" is partitioned by field "create_time".
query sql statement:
SELECT
mid,
COUNT (mid),
string_agg (
create_time ,|| '#' || s_id
ORDER BY
create_time
)
FROM
t1
WHERE
t1.create_time BETWEEN to_timestamp(
'2016-12-19 00:20:00:770',
'yyyy-MM-dd HH24:MI:ss.ff'
)
AND to_timestamp(
'2016-12-19 23:40:00:770',
'yyyy-MM-dd HH24:MI:ss.ff'
)group by mid;

when we explain the sql statement, we find it scan all the partition of table t1 in the query plan, and it has a huge impact on the query performance.
what can i do to solve this problem?
Thanks!