Fix use-after-release mistake in currtid() and currtid2() for views

This issue has been present since the introduction of this code as of
a3519a2 from 2002, and has been found by buildfarm member prion that
uses RELCACHE_FORCE_RELEASE via the tests introduced recently in
e786be5.

Discussion: https://postgr.es/m/20200601022055[email protected]
Backpatch-through: 9.5

diff --git a/src/backend/utils/adt/tid.c b/src/backend/utils/adt/tid.c
index d301c4e2a7bbdc69d0e2c7a17ed56030dd37bd75..e12ec29222bbe6b9bbf9da8c423883f9cbf1bf8e 100644 (file)
--- a/src/backend/utils/adt/tid.c
+++ b/src/backend/utils/adt/tid.c
@@ -338,8 +338,13 @@ currtid_for_view(Relation viewrel, ItemPointer tid)
                    rte = rt_fetch(var->varno, query->rtable);
                    if (rte)
                    {
+                       Datum       result;
+
+                       result = DirectFunctionCall2(currtid_byreloid,
+                                                    ObjectIdGetDatum(rte->relid),
+                                                    PointerGetDatum(tid));
                        table_close(viewrel, AccessShareLock);
-                       return DirectFunctionCall2(currtid_byreloid, ObjectIdGetDatum(rte->relid), PointerGetDatum(tid));
+                       return result;
                    }
                }
            }