On Sat, Apr 18, 2026 at 1:26 PM SATYANARAYANA NARLAPURAM <[email protected]> wrote: > > Hi hackers, > > pg_get_viewdef() fails with ERROR: bogus varlevelsup: 0 offset 0 for any > view containing a GRAPH_TABLE whose COLUMNS clause references an outer > (lateral) > table. This also breaks pg_dump and \d+ for any database containing such a > view. > > Repro: > > CREATE TABLE vtab (id int PRIMARY KEY, name text); > CREATE TABLE etab (eid int PRIMARY KEY, > src int REFERENCES vtab(id), dst int REFERENCES vtab(id)); > CREATE PROPERTY GRAPH g1 > VERTEX TABLES (vtab) > EDGE TABLES (etab KEY (eid) > SOURCE KEY (src) REFERENCES vtab(id) > DESTINATION KEY (dst) REFERENCES vtab(id)); > CREATE TABLE outer_t (val int); > > CREATE VIEW v AS > SELECT * FROM outer_t, > GRAPH_TABLE (g1 MATCH (a IS vtab) > COLUMNS (a.name AS src_name, outer_t.val AS oval)); > > pg_dump -d foo -p 5433 > pg_dump: error: query failed: ERROR: bogus varlevelsup: 0 offset 0 > pg_dump: detail: Query was: SELECT > pg_catalog.pg_get_viewdef('173849'::pg_catalog.oid) AS viewdef > > Problem: > deparse_context context variable declared in the case RTE_GRAPH_TABLE shadows > the function's > deparse_context *context parameter. The zeroed struct has namespaces = NIL, > so when get_rule_expr() > reaches a Var node, get_variable() sees list_length(context->namespaces) == 0 > and raises the error. Property > references are fine because GraphPropertyRef deparsing never touches > namespaces. > > Fix: > Remove the shadowing local variable and pass the outer context pointer to > get_rule_expr(). Attached a patch > with a fix, additionally added a test.
The code doesn't explain why it adds the dummy context but it seemed intentional. But it's not used at other places like deparsing WHERE clause in element patterns or that in the graph_table itself. Since a lateral reference is allowed in COLUMNS clause as well, it doesn't make sense not to pass a context with lateral namespaces. Also there is no comment explaining the dummy context. So your fix looks good to me. I adjusted the surrounding code a bit. I adjusted an existing view for the testing instead of adding a new one with all the additional objects. Since that view definition was getting more complex, I formatted the DDL to be more readable. I also think that we should use prettyFlags to deparse all GRAPH_TABLE components in a human readable form. But that's out of the scope for this patch. PFA updated patch. -- Best Wishes, Ashutosh Bapat
From 6b54b4409df4ce1e8ba50c615e10e5cce3cea075 Mon Sep 17 00:00:00 2001 From: Ashutosh Bapat <[email protected]> Date: Tue, 21 Apr 2026 11:43:43 +0530 Subject: [PATCH v20260421 4/4] pg_get_viewdef() and lateral references in COLUMNS of GRAPH_TABLE Expressions in GRAPH_TABLE COLUMNS list may have lateral references. get_rule_expr() requires lateral namespaces to deparse such references. get_from_clause_item() does not pass them when processing the expressions in COLUMNS list causing ERROR "bogus varlevelsup: 0 offset 0". Fix get_from_clause_item() to pass input deparse_context containing lateral namespaces to get_rule_expr() instead of the dummy context. Reported By: SATYANARAYANA NARLAPURAM <[email protected]> Author: SATYANARAYANA NARLAPURAM <[email protected]> Reviewed By: Ashutosh Bapat <[email protected]> --- src/backend/utils/adt/ruleutils.c | 10 ++------- src/test/regress/expected/graph_table.out | 26 ++++++++++++++++------- src/test/regress/sql/graph_table.sql | 12 +++++++++-- 3 files changed, 30 insertions(+), 18 deletions(-) diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 78587d223cb..c781cdc84d3 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -13091,22 +13091,16 @@ get_from_clause_item(Node *jtnode, Query *query, deparse_context *context) get_graph_pattern_def(rte->graph_pattern, context); appendStringInfoString(buf, " COLUMNS ("); { - ListCell *lc; bool first = true; - foreach(lc, rte->graph_table_columns) + foreach_node(TargetEntry, te, rte->graph_table_columns) { - TargetEntry *te = lfirst_node(TargetEntry, lc); - deparse_context context = {0}; - if (!first) appendStringInfoString(buf, ", "); else first = false; - context.buf = buf; - - get_rule_expr((Node *) te->expr, &context, false); + get_rule_expr((Node *) te->expr, context, false); appendStringInfoString(buf, " AS "); appendStringInfoString(buf, quote_identifier(te->resname)); } diff --git a/src/test/regress/expected/graph_table.out b/src/test/regress/expected/graph_table.out index 057f283c43d..12b8706b5f3 100644 --- a/src/test/regress/expected/graph_table.out +++ b/src/test/regress/expected/graph_table.out @@ -264,7 +264,6 @@ SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.addr ERROR: non-local element variable reference is not supported LINE 1: ...tomers WHERE c.address = 'US' AND c.customer_id = x1.a)-[IS ... ^ -DROP TABLE x1; CREATE TABLE v1 ( id int PRIMARY KEY, vname varchar(10), @@ -922,14 +921,25 @@ SELECT * FROM GRAPH_TABLE (g4 MATCH (s WHERE s.id = 3)-[e]-(d) COLUMNS (s.val, e (2 rows) -- ruleutils reverse parsing -CREATE VIEW customers_us AS SELECT * FROM GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.address = 'US')-[IS customer_orders | customer_wishlists ]->(l IS orders | wishlists)-[ IS list_items]->(p IS products) COLUMNS (c.name AS customer_name, p.name AS product_name)) ORDER BY customer_name, product_name; +-- The query in the view definition is intentionally complex to test one view with many +-- features like label disjunction, lateral references, WHERE clauses in graph +-- patterns. +CREATE VIEW customers_us AS +SELECT g.* FROM x1, + GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.address = 'US' AND c.customer_id = x1.a) + -[IS customer_orders | customer_wishlists ]-> + (l IS orders | wishlists)-[ IS list_items]->(p IS products) + COLUMNS (c.name AS customer_name, p.name AS product_name, x1.a AS a)) g + ORDER BY customer_name, product_name; SELECT pg_get_viewdef('customers_us'::regclass); - pg_get_viewdef --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- - SELECT customer_name, + - product_name + - FROM GRAPH_TABLE (myshop MATCH (c IS customers WHERE ((c.address)::text = 'US'::text))-[IS customer_orders|customer_wishlists]->(l IS orders|wishlists)-[IS list_items]->(p IS products) COLUMNS (c.name AS customer_name, p.name AS product_name))+ - ORDER BY customer_name, product_name; + pg_get_viewdef +---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- + SELECT g.customer_name, + + g.product_name, + + g.a + + FROM x1, + + GRAPH_TABLE (myshop MATCH (c IS customers WHERE (((c.address)::text = 'US'::text) AND (c.customer_id = x1.a)))-[IS customer_orders|customer_wishlists]->(l IS orders|wishlists)-[IS list_items]->(p IS products) COLUMNS (c.name AS customer_name, p.name AS product_name, x1.a AS a)) g+ + ORDER BY g.customer_name, g.product_name; (1 row) -- test view/graph nesting diff --git a/src/test/regress/sql/graph_table.sql b/src/test/regress/sql/graph_table.sql index 278064818ff..a5df4647b6a 100644 --- a/src/test/regress/sql/graph_table.sql +++ b/src/test/regress/sql/graph_table.sql @@ -162,7 +162,6 @@ SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (x1 IS customers WHERE x1.ad -- 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 SELECT x1.a, g.* FROM x1, GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.address = 'US' AND c.customer_id = x1.a)-[IS customer_orders]->(x1 IS orders) COLUMNS (c.name AS customer_name, c.customer_id AS cid, x1.order_id)) g; -- error -DROP TABLE x1; CREATE TABLE v1 ( id int PRIMARY KEY, @@ -525,7 +524,16 @@ SELECT * FROM GRAPH_TABLE (g4 MATCH (s)-[e]-(d) WHERE s.id = 3 COLUMNS (s.val, e SELECT * FROM GRAPH_TABLE (g4 MATCH (s WHERE s.id = 3)-[e]-(d) COLUMNS (s.val, e.val, d.val)) ORDER BY 1, 2, 3; -- ruleutils reverse parsing -CREATE VIEW customers_us AS SELECT * FROM GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.address = 'US')-[IS customer_orders | customer_wishlists ]->(l IS orders | wishlists)-[ IS list_items]->(p IS products) COLUMNS (c.name AS customer_name, p.name AS product_name)) ORDER BY customer_name, product_name; +-- The query in the view definition is intentionally complex to test one view with many +-- features like label disjunction, lateral references, WHERE clauses in graph +-- patterns. +CREATE VIEW customers_us AS +SELECT g.* FROM x1, + GRAPH_TABLE (myshop MATCH (c IS customers WHERE c.address = 'US' AND c.customer_id = x1.a) + -[IS customer_orders | customer_wishlists ]-> + (l IS orders | wishlists)-[ IS list_items]->(p IS products) + COLUMNS (c.name AS customer_name, p.name AS product_name, x1.a AS a)) g + ORDER BY customer_name, product_name; SELECT pg_get_viewdef('customers_us'::regclass); -- test view/graph nesting -- 2.34.1
