1 files changed, 37 insertions, 13 deletions

diff --git a/src/backend/commands/portalcmds.c b/src/backend/commands/portalcmds.c
index 71640b7748f..1d3e39299b9 100644
--- a/src/backend/commands/portalcmds.c
+++ b/src/backend/commands/portalcmds.c
@@ -27,7 +27,9 @@
 #include "commands/portalcmds.h"
 #include "executor/executor.h"
 #include "executor/tstoreReceiver.h"
+#include "rewrite/rewriteHandler.h"
 #include "tcop/pquery.h"
+#include "tcop/tcopprot.h"
 #include "utils/memutils.h"
 #include "utils/snapmgr.h"
 
@@ -35,21 +37,18 @@
 /*
  * PerformCursorOpen
  *		Execute SQL DECLARE CURSOR command.
- *
- * The query has already been through parse analysis, rewriting, and planning.
- * When it gets here, it looks like a SELECT PlannedStmt, except that the
- * utilityStmt field is set.
  */
 void
-PerformCursorOpen(PlannedStmt *stmt, ParamListInfo params,
+PerformCursorOpen(DeclareCursorStmt *cstmt, ParamListInfo params,
 				  const char *queryString, bool isTopLevel)
 {
-	DeclareCursorStmt *cstmt = (DeclareCursorStmt *) stmt->utilityStmt;
+	Query	   *query = (Query *) cstmt->query;
+	List	   *rewritten;
+	PlannedStmt *plan;
 	Portal		portal;
 	MemoryContext oldContext;
 
-	if (cstmt == NULL || !IsA(cstmt, DeclareCursorStmt))
-		elog(ERROR, "PerformCursorOpen called for non-cursor query");
+	Assert(IsA(query, Query));	/* else parse analysis wasn't done */
 
 	/*
 	 * Disallow empty-string cursor name (conflicts with protocol-level
@@ -69,14 +68,39 @@ PerformCursorOpen(PlannedStmt *stmt, ParamListInfo params,
 		RequireTransactionChain(isTopLevel, "DECLARE CURSOR");
 
 	/*
+	 * Parse analysis was done already, but we still have to run the rule
+	 * rewriter.  We do not do AcquireRewriteLocks: we assume the query either
+	 * came straight from the parser, or suitable locks were acquired by
+	 * plancache.c.
+	 *
+	 * Because the rewriter and planner tend to scribble on the input, we make
+	 * a preliminary copy of the source querytree.  This prevents problems in
+	 * the case that the DECLARE CURSOR is in a portal or plpgsql function and
+	 * is executed repeatedly.  (See also the same hack in EXPLAIN and
+	 * PREPARE.)  XXX FIXME someday.
+	 */
+	rewritten = QueryRewrite((Query *) copyObject(query));
+
+	/* SELECT should never rewrite to more or less than one query */
+	if (list_length(rewritten) != 1)
+		elog(ERROR, "non-SELECT statement in DECLARE CURSOR");
+
+	query = (Query *) linitial(rewritten);
+
+	if (query->commandType != CMD_SELECT)
+		elog(ERROR, "non-SELECT statement in DECLARE CURSOR");
+
+	/* Plan the query, applying the specified options */
+	plan = pg_plan_query(query, cstmt->options, params);
+
+	/*
 	 * Create a portal and copy the plan and queryString into its memory.
 	 */
 	portal = CreatePortal(cstmt->portalname, false, false);
 
 	oldContext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
 
-	stmt = copyObject(stmt);
-	stmt->utilityStmt = NULL;	/* make it look like plain SELECT */
+	plan = copyObject(plan);
 
 	queryString = pstrdup(queryString);
 
@@ -84,7 +108,7 @@ PerformCursorOpen(PlannedStmt *stmt, ParamListInfo params,
 					  NULL,
 					  queryString,
 					  "SELECT", /* cursor's query is always a SELECT */
-					  list_make1(stmt),
+					  list_make1(plan),
 					  NULL);
 
 	/*----------
@@ -111,8 +135,8 @@ PerformCursorOpen(PlannedStmt *stmt, ParamListInfo params,
 	portal->cursorOptions = cstmt->options;
 	if (!(portal->cursorOptions & (CURSOR_OPT_SCROLL | CURSOR_OPT_NO_SCROLL)))
 	{
-		if (stmt->rowMarks == NIL &&
-			ExecSupportsBackwardScan(stmt->planTree))
+		if (plan->rowMarks == NIL &&
+			ExecSupportsBackwardScan(plan->planTree))
 			portal->cursorOptions |= CURSOR_OPT_SCROLL;
 		else
 			portal->cursorOptions |= CURSOR_OPT_NO_SCROLL;