avamingli commented on PR #1261:
URL: https://github.com/apache/cloudberry/pull/1261#issuecomment-3135176616
Fix cases where window function operations that couldn't be parallel before
can now be parallel in CBDB, such as window functions within subqueries.
In UPSTREAM select_parallel.sql
> -- Window function calculation can't be pushed to workers.
```sql
explain (costs off, verbose)
select count(*) from tenk1 a where (unique1, two) in
(select unique1, row_number() over() from tenk1 b);
QUERY PLAN
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Finalize Aggregate
Output: count(*)
-> Gather Motion 6:1 (slice1; segments: 6)
Output: (PARTIAL count(*))
-> Partial Aggregate
Output: PARTIAL count(*)
-> Parallel Hash Semi Join
Hash Cond: ((a.unique1 = b.unique1) AND (a.two =
(row_number() OVER (?))))
-> Parallel Seq Scan on public.tenk1 a
Output: a.unique1, a.unique2, a.two, a.four,
a.ten, a.twenty, a.hundred, a.thousand, a.twothousand, a.fivethous, a.tenthous,
a.odd, a.even, a.stringu1, a.stringu2, a.string4
-> Parallel Hash
Output: b.unique1, (row_number() OVER (?))
-> Redistribute Motion 1:6 (slice2; segments: 1)
Output: b.unique1, (row_number() OVER (?))
Hash Key: b.unique1
Hash Module: 3
-> WindowAgg
Output: b.unique1, row_number() OVER
(?)
-> Gather Motion 6:1 (slice3;
segments: 6)
Output: b.unique1
-> Parallel Seq Scan on
public.tenk1 b
Output: b.unique1
Settings: enable_parallel = 'on', min_parallel_table_scan_size = '0',
optimizer = 'off', parallel_setup_cost = '0', parallel_tuple_cost = '0'
Optimizer: Postgres query optimizer
(24 rows)
```
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: commits-unsubscr...@cloudberry.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscr...@cloudberry.apache.org
For additional commands, e-mail: commits-h...@cloudberry.apache.org
