| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | pgsql-performance(at)lists(dot)postgresql(dot)org,Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Zakhar Shapurau <zak(at)zvs(dot)no> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Using GROUPING SETS with more than one set disables predicate pushdown? |
| Date: | 2017-11-21 18:16:56 |
| Message-ID: | 64AFD0D3-9782-4D3B-9366-5B9EEA4DCB0F@anarazel.de |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On November 21, 2017 6:49:26 AM PST, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>Zakhar Shapurau <zak(at)zvs(dot)no> writes:
>
>Presumably, we could examine the grouping sets to identify column(s)
>present in all sets, and then allow the optimization for clauses that
>reference only such columns. Or maybe I'm misreading the comment
>(but then it needs clarification).
By memory that sounds about right. IIRC we'd some slightly more elaborate logic when GS were introduced, but had to take it out as buggy, and it was too late in the development cycle to come up with something better.
Andres
Andres
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Robert Haas | 2017-11-21 18:39:26 | Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade |
| Previous Message | Tom Lane | 2017-11-21 17:01:27 | Re: pg_dump 3 times as slow after 8.4 -> 9.5 upgrade |