| From: | Daniel Gustafsson <daniel(at)yesql(dot)se> |
|---|---|
| To: | Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> |
| Cc: | Alexander Kuzmenkov <a(dot)kuzmenkov(at)postgrespro(dot)ru>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Avoid extra Sort nodes between WindowAggs when sorting can be reused |
| Date: | 2018-07-02 21:19:16 |
| Message-ID: | AC8E7898-F5FD-431B-B1DF-5FBD0B9538E3@yesql.se |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
> On 2 Jul 2018, at 14:01, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> Thank you for updating the patch! There are two review comments.
Thanks for reviewing!
> The current select_active_windows() function compares the all fields
> of WindowClause for the sorting but with this patch we compare only
> tleSortGroupRef, sortop and the number of uniqueOrder. I think this
> leads a degradation as follows.
You are right, that was an oversight. The attached patch takes a stab at
fixing this.
> s/readibility/readability/
Fixed.
cheers ./daniel
| Attachment | Content-Type | Size |
|---|---|---|
| window_prefix_sort-v4.patch | application/octet-stream | 10.1 KB |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2018-07-02 21:25:54 | Re: Unexpected behavior of DROP VIEW/TABLE IF EXISTS |
| Previous Message | Andrew Gierth | 2018-07-02 21:05:27 | Re: Should contrib modules install .h files? |