Collect dependency information for parsed CallStmts.

Parse analysis of a CallStmt will inject mutable information,
for instance the OID of the called procedure, so that subsequent
DDL may create a need to re-parse the CALL.  We failed to detect
this for CALLs in plpgsql routines, because no dependency information
was collected when putting a CallStmt into the plan cache.  That
could lead to misbehavior or strange errors such as "cache lookup
failed".

Before commit ee895a655, the issue would only manifest for CALLs
appearing in atomic contexts, because we re-planned non-atomic
CALLs every time through anyway.

It is now apparent that extract_query_dependencies() probably
needs a special case for every utility statement type for which
stmt_requires_parse_analysis() returns true.  I wanted to add
something like Assert(!stmt_requires_parse_analysis(...)) when
falling out of extract_query_dependencies_walker without doing
anything, but there are API issues as well as a more fundamental
point: stmt_requires_parse_analysis is supposed to be applied to
raw parser output, so it'd be cheating to assume it will give the
correct answer for post-parse-analysis trees.  I contented myself
with adding a comment.

Per bug #18131 from Christian Stork.  Back-patch to all supported
branches.

Discussion: https://postgr.es/m/18131-576854e79c5cd264@postgresql.org

3 files changed, 106 insertions, 2 deletions

diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 5700bfb5cd2..79622008854 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -3565,8 +3565,27 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context)
 		if (query->commandType == CMD_UTILITY)
 		{
 			/*
-			 * Ignore utility statements, except those (such as EXPLAIN) that
-			 * contain a parsed-but-not-planned query.
+			 * This logic must handle any utility command for which parse
+			 * analysis was nontrivial (cf. stmt_requires_parse_analysis).
+			 *
+			 * Notably, CALL requires its own processing.
+			 */
+			if (IsA(query->utilityStmt, CallStmt))
+			{
+				CallStmt   *callstmt = (CallStmt *) query->utilityStmt;
+
+				/* We need not examine funccall, just the transformed exprs */
+				(void) extract_query_dependencies_walker((Node *) callstmt->funcexpr,
+														 context);
+				(void) extract_query_dependencies_walker((Node *) callstmt->outargs,
+														 context);
+				return false;
+			}
+
+			/*
+			 * Ignore other utility statements, except those (such as EXPLAIN)
+			 * that contain a parsed-but-not-planned query.  For those, we
+			 * just need to transfer our attention to the contained query.
 			 */
 			query = UtilityContainsQuery(query->utilityStmt);
 			if (query == NULL)
diff --git a/src/pl/plpgsql/src/expected/plpgsql_call.out b/src/pl/plpgsql/src/expected/plpgsql_call.out
index 7ab23c6a21f..ab16416c1e2 100644
--- a/src/pl/plpgsql/src/expected/plpgsql_call.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_call.out
@@ -483,3 +483,50 @@ BEGIN
 END;
 $$;
 NOTICE:  <NULL>
+-- check that we detect change of dependencies in CALL
+-- atomic and non-atomic call sites used to do this differently, so check both
+CREATE PROCEDURE inner_p (f1 int)
+AS $$
+BEGIN
+  RAISE NOTICE 'inner_p(%)', f1;
+END
+$$ LANGUAGE plpgsql;
+CREATE FUNCTION f(int) RETURNS int AS $$ SELECT $1 + 1 $$ LANGUAGE sql;
+CREATE PROCEDURE outer_p (f1 int)
+AS $$
+BEGIN
+  RAISE NOTICE 'outer_p(%)', f1;
+  CALL inner_p(f(f1));
+END
+$$ LANGUAGE plpgsql;
+CREATE FUNCTION outer_f (f1 int) RETURNS void
+AS $$
+BEGIN
+  RAISE NOTICE 'outer_f(%)', f1;
+  CALL inner_p(f(f1));
+END
+$$ LANGUAGE plpgsql;
+CALL outer_p(42);
+NOTICE:  outer_p(42)
+NOTICE:  inner_p(43)
+SELECT outer_f(42);
+NOTICE:  outer_f(42)
+NOTICE:  inner_p(43)
+ outer_f 
+---------
+ 
+(1 row)
+
+DROP FUNCTION f(int);
+CREATE FUNCTION f(int) RETURNS int AS $$ SELECT $1 + 2 $$ LANGUAGE sql;
+CALL outer_p(42);
+NOTICE:  outer_p(42)
+NOTICE:  inner_p(44)
+SELECT outer_f(42);
+NOTICE:  outer_f(42)
+NOTICE:  inner_p(44)
+ outer_f 
+---------
+ 
+(1 row)
+
diff --git a/src/pl/plpgsql/src/sql/plpgsql_call.sql b/src/pl/plpgsql/src/sql/plpgsql_call.sql
index 14bbffa0b2e..8efc8e823ac 100644
--- a/src/pl/plpgsql/src/sql/plpgsql_call.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_call.sql
@@ -454,3 +454,41 @@ BEGIN
   RAISE NOTICE '%', v_Text;
 END;
 $$;
+
+
+-- check that we detect change of dependencies in CALL
+-- atomic and non-atomic call sites used to do this differently, so check both
+
+CREATE PROCEDURE inner_p (f1 int)
+AS $$
+BEGIN
+  RAISE NOTICE 'inner_p(%)', f1;
+END
+$$ LANGUAGE plpgsql;
+
+CREATE FUNCTION f(int) RETURNS int AS $$ SELECT $1 + 1 $$ LANGUAGE sql;
+
+CREATE PROCEDURE outer_p (f1 int)
+AS $$
+BEGIN
+  RAISE NOTICE 'outer_p(%)', f1;
+  CALL inner_p(f(f1));
+END
+$$ LANGUAGE plpgsql;
+
+CREATE FUNCTION outer_f (f1 int) RETURNS void
+AS $$
+BEGIN
+  RAISE NOTICE 'outer_f(%)', f1;
+  CALL inner_p(f(f1));
+END
+$$ LANGUAGE plpgsql;
+
+CALL outer_p(42);
+SELECT outer_f(42);
+
+DROP FUNCTION f(int);
+CREATE FUNCTION f(int) RETURNS int AS $$ SELECT $1 + 2 $$ LANGUAGE sql;
+
+CALL outer_p(42);
+SELECT outer_f(42);