database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-11 00:12:06 +03:00
Code Activity

Pull up ANY-SUBLINK with the necessary lateral support.

Browse Source 
For ANY-SUBLINK, we adopted a two-stage pull-up approach to handle
different types of scenarios. In the first stage, the sublink is pulled up
as a subquery. Because of this, when writing this code, we did not have
the ability to perform lateral joins, and therefore, we were unable to
pull up Var with varlevelsup=1. Now that we have the ability to use
lateral joins, we can eliminate this limitation.

Author: Andy Fan <zhihui.fan1213@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Richard Guo <guofenglinux@gmail.com>
Reviewed-by: Alena Rybakina <lena.ribackina@yandex.ru>
Reviewed-by: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
This commit is contained in:
Alexander Korotkov
2024-02-15 12:05:52 +02:00
parent 995d400cec
commit 9f13376396
7 changed files with 192 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
src/backend/optimizer/plan/subselect.c
View File

@@ -1278,14 +1278,23 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
List *subquery_vars;
Node *quals;
ParseState *pstate;
Relids sub_ref_outer_relids;
bool use_lateral;
Assert(sublink->subLinkType == ANY_SUBLINK);
/*
* The sub-select must not refer to any Vars of the parent query. (Vars of
* higher levels should be okay, though.)
* If the sub-select refers to any Vars of the parent query, we so let's
* considering it as LATERAL. (Vars of higher levels don't matter here.)
*/
if (contain_vars_of_level((Node *) subselect, 1))
sub_ref_outer_relids = pull_varnos_of_level(NULL, (Node *) subselect, 1);
use_lateral = !bms_is_empty(sub_ref_outer_relids);
/*
* Check that sub-select refers nothing outside of available_rels of the
* parent query.
*/
if (!bms_is_subset(sub_ref_outer_relids, available_rels))
return NULL;
/*
@@ -1323,7 +1332,7 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
nsitem = addRangeTableEntryForSubquery(pstate,
subselect,
makeAlias("ANY_subquery", NIL),
false,
use_lateral,
false);
rte = nsitem->p_rte;
parse->rtable = lappend(parse->rtable, rte);