From 986085a7f08c72219abf47f8b968213e81ab943c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 30 Apr 2006 18:30:40 +0000
Subject: Improve the representation of FOR UPDATE/FOR SHARE so that we can
 support both FOR UPDATE and FOR SHARE in one command, as well as both NOWAIT
 and normal WAIT behavior.  The more general code is actually simpler and
 cleaner.

---
 src/backend/parser/parse_relation.c | 38 +++++++++++++++++++++++++++++++------
 1 file changed, 32 insertions(+), 6 deletions(-)

(limited to 'src/backend/parser/parse_relation.c')

diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index d3e138e8ecb..10f71712ff6 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.122 2006/03/23 00:19:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.123 2006/04/30 18:30:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1001,6 +1001,8 @@ addRangeTableEntryForJoin(ParseState *pstate,
 
 /*
  * Has the specified refname been selected FOR UPDATE/FOR SHARE?
+ *
+ * Note: we pay no attention to whether it's FOR UPDATE vs FOR SHARE.
  */
 static bool
 isLockedRel(ParseState *pstate, char *refname)
@@ -1008,9 +1010,13 @@ isLockedRel(ParseState *pstate, char *refname)
 	/* Outer loop to check parent query levels as well as this one */
 	while (pstate != NULL)
 	{
-		if (pstate->p_locking_clause)
+		ListCell   *l;
+
+		foreach(l, pstate->p_locking_clause)
 		{
-			if (pstate->p_locking_clause->lockedRels == NIL)
+			LockingClause *lc = (LockingClause *) lfirst(l);
+
+			if (lc->lockedRels == NIL)
 			{
 				/* all tables used in query */
 				return true;
@@ -1018,11 +1024,11 @@ isLockedRel(ParseState *pstate, char *refname)
 			else
 			{
 				/* just the named tables */
-				ListCell   *l;
+				ListCell   *l2;
 
-				foreach(l, pstate->p_locking_clause->lockedRels)
+				foreach(l2, lc->lockedRels)
 				{
-					char	   *rname = strVal(lfirst(l));
+					char	   *rname = strVal(lfirst(l2));
 
 					if (strcmp(refname, rname) == 0)
 						return true;
@@ -1702,6 +1708,26 @@ get_tle_by_resno(List *tlist, AttrNumber resno)
 	return NULL;
 }
 
+/*
+ * Given a Query and rangetable index, return relation's RowMarkClause if any
+ *
+ * Returns NULL if relation is not selected FOR UPDATE/SHARE
+ */
+RowMarkClause *
+get_rowmark(Query *qry, Index rtindex)
+{
+	ListCell   *l;
+
+	foreach(l, qry->rowMarks)
+	{
+		RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+
+		if (rc->rti == rtindex)
+			return rc;
+	}
+	return NULL;
+}
+
 /*
  *	given relation and att name, return attnum of variable
  *
-- 
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