mirror of
https://github.com/postgres/postgres.git
synced 2026-02-24 18:37:22 -05:00
6b701eaaa9
The trouble with doing this is that an apparently-constant subquery output column isn't really constant if it is a grouping column that appears in only some of the grouping sets. A qual using such a column would be subject to incorrect const-folding after push-down, as seen in bug #16585 from Paul Sivash. To fix, just disable qual pushdown altogether if the sub-query has nonempty groupingSets. While we could imagine far less restrictive solutions, there is not much point in working harder right now, because subquery_planner() won't move HAVING clauses to WHERE within such a subquery. If the qual stays in HAVING it's not going to be a lot more useful than if we'd kept it at the outer level. Having said that, this restriction could be removed if we used a parsetree representation that distinguished such outputs from actual constants, which is something I hope to do in future. Hence, make the patch a minimal addition rather than integrating it more tightly (e.g. by renumbering the existing items in subquery_is_pushdown_safe's comment). Back-patch to 9.5 where grouping sets were introduced. Discussion: https://postgr.es/m/16585-9d8c340d23ade8c1@postgresql.org |
||
|---|---|---|
| .. | ||
| backend | ||
| bin | ||
| common | ||
| fe_utils | ||
| include | ||
| interfaces | ||
| makefiles | ||
| pl | ||
| port | ||
| template | ||
| test | ||
| timezone | ||
| tools | ||
| tutorial | ||
| .gitignore | ||
| DEVELOPERS | ||
| Makefile | ||
| Makefile.global.in | ||
| Makefile.shlib | ||
| nls-global.mk | ||