Re: Convert NOT IN sublinks to anti-joins when safe - Mailing list pgsql-hackers
| From | wenhui qiu |
|---|---|
| Subject | Re: Convert NOT IN sublinks to anti-joins when safe |
| Date | |
| Msg-id | CAGjGUA+Xi++Qd9kVjgSjFADh5E0aXKnttEN-rXfGWL+mj3eU2g@mail.gmail.com Whole thread |
| In response to | Re: Convert NOT IN sublinks to anti-joins when safe (Japin Li <japinli@hotmail.com>) |
| List | pgsql-hackers |
HI Japin
```
> Just a quick note: I think `foreach_ptr` is more appropriate here than `foreach`.
Thank you review this path , I think using foreach_node should be safe
```
#define foreach_ptr(type, var, lst) foreach_internal(type, *, var, lst, lfirst)
#define foreach_int(var, lst) foreach_internal(int, , var, lst, lfirst_int)
#define foreach_oid(var, lst) foreach_internal(Oid, , var, lst, lfirst_oid)
#define foreach_xid(var, lst) foreach_internal(TransactionId, , var, lst, lfirst_xid)
/*
* The internal implementation of the above macros. Do not use directly.
*
* This macro actually generates two loops in order to declare two variables of
* different types. The outer loop only iterates once, so we expect optimizing
* compilers will unroll it, thereby optimizing it away.
*/
#define foreach_internal(type, pointer, var, lst, func) \
for (type pointer var = 0, pointer var##__outerloop = (type pointer) 1; \
var##__outerloop; \
var##__outerloop = 0) \
for (ForEachState var##__state = {(lst), 0}; \
(var##__state.l != NIL && \
var##__state.i < var##__state.l->length && \
(var = (type pointer) func(&var##__state.l->elements[var##__state.i]), true)); \
var##__state.i++)
/*
* foreach_node -
* The same as foreach_ptr, but asserts that the element is of the specified
* node type.
*/
#define foreach_node(type, var, lst) \
for (type * var = 0, *var##__outerloop = (type *) 1; \
var##__outerloop; \
var##__outerloop = 0) \
for (ForEachState var##__state = {(lst), 0}; \
(var##__state.l != NIL && \
var##__state.i < var##__state.l->length && \
(var = lfirst_node(type, &var##__state.l->elements[var##__state.i]), true)); \
var##__state.i++)
On Thu, Mar 5, 2026 at 9:58 AM Japin Li <japinli@hotmail.com> wrote:
Hi, Richard
On Wed, 04 Mar 2026 at 18:52, Richard Guo <guofenglinux@gmail.com> wrote:
> On Sat, Feb 14, 2026 at 4:37 PM Richard Guo <guofenglinux@gmail.com> wrote:
>> On Thu, Feb 5, 2026 at 3:51 PM Richard Guo <guofenglinux@gmail.com> wrote:
>> > Attached is the updated patch, which adds the check requiring the
>> > operator to be a member of a btree or hash opfamily.
>
>> Attached is another updated patch rebased on current master, with the
>> addition of support for RowCompareExpr to handle multi-column ordering
>> operations; otherwise unchanged.
>
> Attached is another updated patch rebased on current master, with some
> minor cosmetic adjustments; nothing essential has changed.
>
Thank you for working on this!
Just a quick note: I think `foreach_ptr` is more appropriate here than `foreach`.
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 299b3354f6d..0d31861da7f 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -1484,7 +1484,6 @@ sublink_testexpr_is_not_nullable(PlannerInfo *root, SubLink *sublink)
{
Node *testexpr = sublink->testexpr;
List *outer_exprs = NIL;
- ListCell *lc;
/* Punt if sublink is not in the expected format */
if (sublink->subLinkType != ANY_SUBLINK || testexpr == NULL)
@@ -1514,10 +1513,8 @@ sublink_testexpr_is_not_nullable(PlannerInfo *root, SubLink *sublink)
/* multi-column equality or inequality checks */
BoolExpr *bexpr = (BoolExpr *) testexpr;
- foreach(lc, bexpr->args)
+ foreach_ptr(OpExpr, opexpr, bexpr->args)
{
- OpExpr *opexpr = (OpExpr *) lfirst(lc);
-
if (!IsA(opexpr, OpExpr))
return false;
@@ -1537,10 +1534,8 @@ sublink_testexpr_is_not_nullable(PlannerInfo *root, SubLink *sublink)
/* multi-column ordering checks */
RowCompareExpr *rcexpr = (RowCompareExpr *) testexpr;
- foreach(lc, rcexpr->opnos)
+ foreach_oid(opno, rcexpr->opnos)
{
- Oid opno = lfirst_oid(lc);
-
/* verify operator safety; see comment above */
if (!op_is_safe_index_member(opno))
return false;
@@ -1566,10 +1561,8 @@ sublink_testexpr_is_not_nullable(PlannerInfo *root, SubLink *sublink)
flatten_join_alias_vars(root, root->parse, (Node *) outer_exprs);
/* Check that every outer expression is non-nullable */
- foreach(lc, outer_exprs)
+ foreach_ptr(Expr, expr, outer_exprs)
{
- Expr *expr = (Expr *) lfirst(lc);
-
/*
* We have already collected relation-level not-null constraints for
* the outer query, so we can consult the global hash table for
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index c47c9da4a9b..3f3baf2149a 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -2052,7 +2052,6 @@ query_outputs_are_not_nullable(Query *query)
List *safe_quals = NIL;
List *nonnullable_vars = NIL;
bool computed_nonnullable_vars = false;
- ListCell *tl;
/*
* If the query contains set operations, punt. The set ops themselves
@@ -2083,9 +2082,8 @@ query_outputs_are_not_nullable(Query *query)
/*
* Examine each targetlist entry to prove that it can't produce NULL.
*/
- foreach(tl, query->targetList)
+ foreach_ptr(TargetEntry, tle, query->targetList)
{
- TargetEntry *tle = (TargetEntry *) lfirst(tl);
Expr *expr = tle->expr;
/* Resjunk columns can be ignored: they don't produce output values */
@@ -2194,11 +2192,10 @@ find_subquery_safe_quals(Node *jtnode, List **safe_quals)
else if (IsA(jtnode, FromExpr))
{
FromExpr *f = (FromExpr *) jtnode;
- ListCell *lc;
/* All elements of the FROM list are allowable */
- foreach(lc, f->fromlist)
- find_subquery_safe_quals((Node *) lfirst(lc), safe_quals);
+ foreach_ptr(Node, node, f->fromlist)
+ find_subquery_safe_quals(node, safe_quals);
/* ... and its WHERE quals are too */
if (f->quals)
*safe_quals = lappend(*safe_quals, f->quals);
> - Richard
>
> [2. text/x-diff; v4-0001-Convert-NOT-IN-sublinks-to-anti-joins-when-safe.patch]...
--
Regards,
Japin Li
ChengDu WenWu Information Technology Co., Ltd.
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