From e182cc2bea150680f5664cac3cec70c5e9842418 Mon Sep 17 00:00:00 2001 From: Ashutosh Bapat Date: Tue, 2 Jun 2026 15:51:41 +0530 Subject: [PATCH v20260602 10/10] Fix LATERAL references in GRAPH_TABLE with multi-label pattern When rewriting a GRAPH_TABLE into a subquery replace_property_refs_mutator() bumps levelsup of lateral references by one so that reference outside the subquery. This works for path patterns which result in only one path query. Patterns that produce multiple path queries are rewritten as UNION of path queries. Since every path query becomes a subquery of UNION statement, the levelsup of lateral references in those path queries need additional bump. This adjustment was missing resulting in the lateral references being interpreted as references in the UNION query itself. This caused different symptoms like a crash in create_lateral_join_info() or error "plan should not reference subplan's variable". The symptoms varied depending upon the number of RangeTblEntries in the UNION statement. This commit adds the missing adjustment. Author: Ayush Tiwari Author: Satya Narlapuram Reviewed-by: Ashutosh Bapat Discussion: https://www.postgresql.org/message-id/CAHg+QDfnLzsgjaQ_CiKSpP4JH3MKOiwoawEcCzXa9uYr45yiWw@mail.gmail.com --- src/backend/rewrite/rewriteGraphTable.c | 7 +++++++ src/test/regress/expected/graph_table.out | 14 ++++++++++++++ src/test/regress/sql/graph_table.sql | 6 ++++++ 3 files changed, 27 insertions(+) diff --git a/src/backend/rewrite/rewriteGraphTable.c b/src/backend/rewrite/rewriteGraphTable.c index 2292ca6dcee..7df7f9fd70a 100644 --- a/src/backend/rewrite/rewriteGraphTable.c +++ b/src/backend/rewrite/rewriteGraphTable.c @@ -720,6 +720,13 @@ generate_setop_from_pathqueries(List *pathqueries, List **rtable, List **targetl lquery = linitial_node(Query, pathqueries); + /* + * Each path query will become a subquery of the UNION statement. So any + * Vars that already refer outside the path query must be adjusted for + * additional query level. + */ + IncrementVarSublevelsUp((Node *) lquery, 1, 1); + pni = addRangeTableEntryForSubquery(make_parsestate(NULL), lquery, NULL, false, false); *rtable = lappend(*rtable, pni->p_rte); diff --git a/src/test/regress/expected/graph_table.out b/src/test/regress/expected/graph_table.out index 475ac20d376..c229212cb51 100644 --- a/src/test/regress/expected/graph_table.out +++ b/src/test/regress/expected/graph_table.out @@ -263,6 +263,20 @@ SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (x1 IS customers WHERE x1.ad 2 | customer1 | 1 | 1 (2 rows) +-- lateral reference with multi-label pattern, which is rewritten as UNION of +-- path queries +SELECT x1.a, g.* FROM x1, + GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.customer_id = x1.a)-[IS customer_orders | customer_wishlists]->(l IS lists)-[IS list_items]->(p IS products) + COLUMNS (x1.a AS outer_id, c.name AS customer_name, p.name AS product_name, l.list_type)) g + ORDER BY 1, 3, 4, 5; + a | outer_id | customer_name | product_name | list_type +---+----------+---------------+--------------+----------- + 1 | 1 | customer1 | product1 | order + 1 | 1 | customer1 | product2 | order + 2 | 2 | customer2 | product1 | order + 2 | 2 | customer2 | product1 | wishlist +(4 rows) + -- non-local property references are not allowed, even if a lateral column -- reference is available SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (x1 IS customers)-[IS customer_orders]->(o IS orders WHERE o.order_id = x1.a) COLUMNS (x1.name AS customer_name, x1.customer_id AS cid, o.order_id)) g; -- error diff --git a/src/test/regress/sql/graph_table.sql b/src/test/regress/sql/graph_table.sql index 5412f10ac3c..e30c908dccc 100644 --- a/src/test/regress/sql/graph_table.sql +++ b/src/test/regress/sql/graph_table.sql @@ -160,6 +160,12 @@ CREATE TABLE x1 (a int, address text); INSERT INTO x1 VALUES (1, 'one'), (2, 'two'); SELECT * FROM x1, GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.address = 'US' AND c.customer_id = x1.a)-[IS customer_orders]->(o IS orders) COLUMNS (c.name AS customer_name, c.customer_id AS cid)); SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (x1 IS customers WHERE x1.address = 'US')-[IS customer_orders]->(o IS orders) COLUMNS (x1.name AS customer_name, x1.customer_id AS cid, o.order_id)) g; +-- lateral reference with multi-label pattern, which is rewritten as UNION of +-- path queries +SELECT x1.a, g.* FROM x1, + GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.customer_id = x1.a)-[IS customer_orders | customer_wishlists]->(l IS lists)-[IS list_items]->(p IS products) + COLUMNS (x1.a AS outer_id, c.name AS customer_name, p.name AS product_name, l.list_type)) g + ORDER BY 1, 3, 4, 5; -- non-local property references are not allowed, even if a lateral column -- reference is available SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (x1 IS customers)-[IS customer_orders]->(o IS orders WHERE o.order_id = x1.a) COLUMNS (x1.name AS customer_name, x1.customer_id AS cid, o.order_id)) g; -- error -- 2.34.1