From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 29 May 2026 17:51:09 +0000 (-0400)
Subject: pg_plan_advice: DO_NOT_SCAN is a simple tag, not a generic one.
X-Git-Tag: REL_19_BETA1~20
X-Git-Url: http://git.ipfire.org/index.cgi?a=commitdiff_plain;h=b1901e2895e08f57a5fedfd27375babd6c633893;p=thirdparty%2Fpostgresql.git

pg_plan_advice: DO_NOT_SCAN is a simple tag, not a generic one.

Generic tags allow sublists, e.g. MERGE_JOIN((x y)), but simple
tags do not, e.g. SEQ_SCAN(x) is valid but SEQ_SCAN((x)) is not.
DO_NOT_SCAN was intended to be simple tag, but was accidentally
implemented as a generic one. This could result in assertion
failures. Repair.

Reported-by: Nikita Kalinin <n.kalinin@postgrespro.ru>
Analyzed-by: Tender Wang <tndrwang@gmail.com>
Analyzed-by: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: http://postgr.es/m/19493-5878eac7a2525c23@postgresql.org
---

diff --git a/contrib/pg_plan_advice/expected/syntax.out b/contrib/pg_plan_advice/expected/syntax.out
index c3f2cbd6dca..c61fd73a385 100644
--- a/contrib/pg_plan_advice/expected/syntax.out
+++ b/contrib/pg_plan_advice/expected/syntax.out
@@ -126,6 +126,9 @@ DETAIL:  Could not parse advice: syntax error at or near "123"
 SET pg_plan_advice.advice = 'SEQ_SCAN((x))';
 ERROR:  invalid value for parameter "pg_plan_advice.advice": "SEQ_SCAN((x))"
 DETAIL:  Could not parse advice: syntax error at or near "("
+SET pg_plan_advice.advice = 'DO_NOT_SCAN((x))';
+ERROR:  invalid value for parameter "pg_plan_advice.advice": "DO_NOT_SCAN((x))"
+DETAIL:  Could not parse advice: syntax error at or near "("
 SET pg_plan_advice.advice = 'GATHER(((x)))';
 ERROR:  invalid value for parameter "pg_plan_advice.advice": "GATHER(((x)))"
 DETAIL:  Could not parse advice: syntax error at or near "("
diff --git a/contrib/pg_plan_advice/pgpa_parser.y b/contrib/pg_plan_advice/pgpa_parser.y
index 598974d3f22..5811a6e5e56 100644
--- a/contrib/pg_plan_advice/pgpa_parser.y
+++ b/contrib/pg_plan_advice/pgpa_parser.y
@@ -106,6 +106,8 @@ advice_item: TOK_TAG_JOIN_ORDER '(' join_order_target_list ')'
 			$$ = palloc0_object(pgpa_advice_item);
 			if (strcmp($1, "bitmap_heap_scan") == 0)
 				$$->tag = PGPA_TAG_BITMAP_HEAP_SCAN;
+			else if (strcmp($1, "do_not_scan") == 0)
+				$$->tag = PGPA_TAG_DO_NOT_SCAN;
 			else if (strcmp($1, "no_gather") == 0)
 				$$->tag = PGPA_TAG_NO_GATHER;
 			else if (strcmp($1, "seq_scan") == 0)
diff --git a/contrib/pg_plan_advice/pgpa_scanner.l b/contrib/pg_plan_advice/pgpa_scanner.l
index 3b3be6eb727..e6d60f57e1e 100644
--- a/contrib/pg_plan_advice/pgpa_scanner.l
+++ b/contrib/pg_plan_advice/pgpa_scanner.l
@@ -128,7 +128,8 @@ xcinside		[^*/]+
 					else if (tag == PGPA_TAG_SEQ_SCAN ||
 							 tag == PGPA_TAG_TID_SCAN ||
 							 tag == PGPA_TAG_BITMAP_HEAP_SCAN ||
-							 tag == PGPA_TAG_NO_GATHER)
+							 tag == PGPA_TAG_NO_GATHER ||
+							 tag == PGPA_TAG_DO_NOT_SCAN)
 						return TOK_TAG_SIMPLE;
 					else
 						return TOK_TAG_GENERIC;
diff --git a/contrib/pg_plan_advice/sql/syntax.sql b/contrib/pg_plan_advice/sql/syntax.sql
index f274fa48636..3f94b5f8bf3 100644
--- a/contrib/pg_plan_advice/sql/syntax.sql
+++ b/contrib/pg_plan_advice/sql/syntax.sql
@@ -41,6 +41,7 @@ SET pg_plan_advice.advice = '123';
 -- except for JOIN_ORDER, allow at most one level of sublist. Hence, these
 -- examples should error out.
 SET pg_plan_advice.advice = 'SEQ_SCAN((x))';
+SET pg_plan_advice.advice = 'DO_NOT_SCAN((x))';
 SET pg_plan_advice.advice = 'GATHER(((x)))';
 
 -- Legal comments.