database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Support PlaceHolderVars in MERGE actions.

Browse Source 
preprocess_targetlist thought PHVs couldn't appear here.
It was mistaken, as per report from Önder Kalacı.

Surveying other pull_var_clause calls, I noted no similar errors,
but I did notice that qual_is_pushdown_safe's assertion about
!contain_window_function was pointless, because the following
pull_var_clause call would complain about them anyway.  In HEAD
only, remove the redundant Assert and improve the commentary.

Discussion: https://postgr.es/m/CACawEhUuum-gC_2S3sXLTcsk7bUSPSHOD+g1ZpfKaDK-KKPPWA@mail.gmail.com
This commit is contained in:
Tom Lane
2023-03-15 11:59:18 -04:00
parent a0137388cb
commit e3ac85014e
4 changed files with 41 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/optimizer/path/allpaths.c
View File

@ -3839,18 +3839,16 @@ qual_is_pushdown_safe(Query *subquery, Index rti, RestrictInfo *rinfo,
contain_leaked_vars(qual))
return false;
/*
* It would be unsafe to push down window function calls, but at least for
* the moment we could never see any in a qual anyhow. (The same applies
* to aggregates, which we check for in pull_var_clause below.)
*/
Assert(!contain_window_function(qual));
/*
* Examine all Vars used in clause. Since it's a restriction clause, all
* such Vars must refer to subselect output columns ... unless this is
* part of a LATERAL subquery, in which case there could be lateral
* references.
*
* By omitting the relevant flags, this also gives us a cheap sanity check
* that no aggregates or window functions appear in the qual. Those would
* be unsafe to push down, but at least for the moment we could never see
* any in a qual anyhow.
*/
vars = pull_var_clause(qual, PVC_INCLUDE_PLACEHOLDERS);
foreach(vl, vars)

12
src/backend/optimizer/prep/preptlist.c
View File

@ -155,17 +155,15 @@ preprocess_targetlist(PlannerInfo *root)
extract_update_targetlist_colnos(action->targetList);
/*
* Add resjunk entries for any Vars used in each action's
* targetlist and WHEN condition that belong to relations other
* than target. Note that aggregates, window functions and
* placeholder vars are not possible anywhere in MERGE's WHEN
* clauses. (PHVs may be added later, but they don't concern us
* here.)
* Add resjunk entries for any Vars and PlaceHolderVars used in
* each action's targetlist and WHEN condition that belong to
* relations other than the target. We don't expect to see any
* aggregates or window functions here.
*/
vars = pull_var_clause((Node *)
list_concat_copy((List *) action->qual,
action->targetList),
0);
PVC_INCLUDE_PLACEHOLDERS);
foreach(l2, vars)
{
Var *var = (Var *) lfirst(l2);