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.
Thanks,
Satya
0001-Fix-pg_get_viewdef-crash-for-GRAPH_TABLE-views-with-.patch
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