From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 12 Dec 2002 16:16:58 +0000 (+0000)
Subject: Back-patch fix to prevent core dump in EXPLAIN if optimizer has
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=b661c7fb6158f4564d65598e7464ad4881b901bf;p=users%2Fbernd%2Fpostgres.git

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 6ddf2e28b8..44ad03a673 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -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));