Fix possible loss of sync between rectypeid and underlying PLpgSQL_type.

When revalidate_rectypeid() acts to update a stale record type OID
in plpgsql's data structures, it fixes the active PLpgSQL_rec struct
as well as the PLpgSQL_type struct it references.  However, the latter
is shared across function executions while the former is not.  In a
later function execution, the PLpgSQL_rec struct would be reinitialized
by copy_plpgsql_datums and would then contain a stale type OID,
typically leading to "could not open relation with OID NNNN" errors.
revalidate_rectypeid() can easily fix this, fortunately, just by
treating typ->typoid as authoritative.

Per report and diagnosis from Ashutosh Sharma, though this is not his
suggested fix.  Back-patch to v11 where this code came in.

Discussion: https://postgr.es/m/CAE9k0Pkd4dZwt9J5pS9xhJFWpUtqs05C9xk_GEwPzYdV=GxwWg@mail.gmail.com

diff --git a/src/pl/plpgsql/src/expected/plpgsql_record.out b/src/pl/plpgsql/src/expected/plpgsql_record.out
index 403c6358b9319d659af6d7e2459a915d6f03287f..cf6089cbb219262a44be0a5f2ffe623e60d29b4f 100644 (file)
--- a/src/pl/plpgsql/src/expected/plpgsql_record.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_record.out
@@ -476,6 +476,12 @@ select sillyaddtwo(42);
           44
 (1 row)
 
+select sillyaddtwo(43);
+ sillyaddtwo 
+-------------
+          45
+(1 row)
+
 -- check access to system columns in a record variable
 create function sillytrig() returns trigger language plpgsql as
 $$begin

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index 2deb7c0b12ac66977fc1256ef21671e309fda39d..d1775d3615230d7b9689f83cdd08fc5bc823a5dd 100644 (file)
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -6858,7 +6858,16 @@ revalidate_rectypeid(PLpgSQL_rec *rec)
        Assert(typ != NULL);
        if (typ->tcache &&
                typ->tcache->tupDesc_identifier == typ->tupdesc_id)
-               return;                                 /* known up-to-date */
+       {
+               /*
+                * Although *typ is known up-to-date, it's possible that rectypeid
+                * isn't, because *rec is cloned during each function startup from a
+                * copy that we don't have a good way to update.  Hence, forcibly fix
+                * rectypeid before returning.
+                */
+               rec->rectypeid = typ->typoid;
+               return;
+       }
 
        /*
         * typcache entry has suffered invalidation, so re-look-up the type name

diff --git a/src/pl/plpgsql/src/sql/plpgsql_record.sql b/src/pl/plpgsql/src/sql/plpgsql_record.sql
index e93aeac5b9aa47f13461a4518ff0c20ec0bec53c..128846e6108231a8a22116da60e03a41e188bf86 100644 (file)
--- a/src/pl/plpgsql/src/sql/plpgsql_record.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_record.sql
@@ -303,6 +303,7 @@ drop table mutable2;
 select sillyaddtwo(42);  -- fail
 create table mutable2(f0 text, f1 int, f2 text);
 select sillyaddtwo(42);
+select sillyaddtwo(43);
 
 -- check access to system columns in a record variable