Back-patch fix to prevent core dump in EXPLAIN if optimizer has

simplified function call to a constant.  (7.3 won't actually execute
such a plan anyway, but core dump is bad regardless.)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index ca6b37847ee2fbad4028fbc54c24620d860f2f33..bfb60e56640ea5180a74f77b05a1a823773762ad 100644 (file)
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -5,7 +5,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994-5, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.89.2.1 2002/12/06 19:28:13 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.89.2.2 2002/12/12 16:16:58 tgl Exp $
  *
  */
 
@@ -367,19 +367,28 @@ explain_outNode(StringInfo str, Plan *plan, Plan *outer_plan,
                RangeTblEntry *rte = rt_fetch(((Scan *) plan)->scanrelid,
                                              es->rtable);
                Expr       *expr;
-               Func       *funcnode;
-               Oid         funcid;
                char       *proname;
 
                /* Assert it's on a RangeFunction */
                Assert(rte->rtekind == RTE_FUNCTION);
 
+               /*
+                * If the expression is still a function call, we can get
+                * the real name of the function.  Otherwise, punt (this
+                * can happen if the optimizer simplified away the function
+                * call, for example).
+                */
                expr = (Expr *) rte->funcexpr;
-               funcnode = (Func *) expr->oper;
-               funcid = funcnode->funcid;
-
-               /* We only show the func name, not schema name */
-               proname = get_func_name(funcid);
+               if (expr && IsA(expr, Expr) && expr->opType == FUNC_EXPR)
+               {
+                   Func       *funcnode = (Func *) expr->oper;
+                   Oid         funcid = funcnode->funcid;
+
+                   /* We only show the func name, not schema name */
+                   proname = get_func_name(funcid);
+               }
+               else
+                   proname = rte->eref->aliasname;
 
                appendStringInfo(str, " on %s",
                                 quote_identifier(proname));