| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Richard Guo <guofenglinux(at)gmail(dot)com> |
| Cc: | pgsql-committers(at)lists(dot)postgresql(dot)org |
| Subject: | Re: pgsql: Avoid mislabeling of lateral references when pulling up a subque |
| Date: | 2024-11-29 21:31:24 |
| Message-ID: | 590235.1732915884@sss.pgh.pa.us |
| Views: | Whole Thread | Raw Message | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-committers |
I wrote:
> The ideas I'd been toying with last night involved a pre-scan over
> the join tree to calculate the potential nullingrels of each leaf RTE
> (same idea as RelOptInfo.nulling_relids, but of course we don't have
> any RelOptInfos yet). That seems painful though because we'd have to
> update the data structure somehow after each subquery pullup.
I realized that we can make that work by doing the pre-calculation
at the start of each pull_up_simple_subquery. We only have to do
it for subqueries marked LATERAL, so this doesn't seem too horribly
inefficient. Draft patch attached. I didn't spend effort on
devising test cases, but it works for your example.
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| v2-0001-Fix-wrong-varnullingrels.patch | text/x-diff | 7.9 KB |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Richard Guo | 2024-11-30 03:09:18 | Re: pgsql: Avoid mislabeling of lateral references when pulling up a subque |
| Previous Message | Tom Lane | 2024-11-29 19:17:29 | Re: pgsql: Avoid mislabeling of lateral references when pulling up a subque |