Implement SQL-standard WITH clauses, including WITH RECURSIVE.

There are some unimplemented aspects: recursive queries must use UNION ALL
(should allow UNION too), and we don't have SEARCH or CYCLE clauses.
These might or might not get done for 8.4, but even without them it's a
pretty useful feature.

There are also a couple of small loose ends and definitional quibbles,
which I'll send a memo about to pgsql-hackers shortly.  But let's land
the patch now so we can get on with other development.

Yoshiyuki Asaba, with lots of help from Tatsuo Ishii and Tom Lane

1 files changed, 37 insertions, 1 deletions

diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 2f0ed9a5d79..cdf06b00207 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.103 2008/09/09 18:58:08 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.104 2008/10/04 21:56:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -183,6 +183,20 @@ typedef struct Append
 } Append;
 
 /* ----------------
+ *	RecursiveUnion node -
+ *		Generate a recursive union of two subplans.
+ *
+ * The "outer" subplan is always the non-recursive term, and the "inner"
+ * subplan is the recursive term.
+ * ----------------
+ */
+typedef struct RecursiveUnion
+{
+	Plan		plan;
+	int			wtParam;		/* ID of Param representing work table */
+} RecursiveUnion;
+
+/* ----------------
  *	 BitmapAnd node -
  *		Generate the intersection of the results of sub-plans.
  *
@@ -358,6 +372,28 @@ typedef struct ValuesScan
 	List	   *values_lists;	/* list of expression lists */
 } ValuesScan;
 
+/* ----------------
+ *		CteScan node
+ * ----------------
+ */
+typedef struct CteScan
+{
+	Scan		scan;
+	int			ctePlanId;		/* ID of init SubPlan for CTE */
+	int			cteParam;		/* ID of Param representing CTE output */
+} CteScan;
+
+/* ----------------
+ *		WorkTableScan node
+ * ----------------
+ */
+typedef struct WorkTableScan
+{
+	Scan		scan;
+	int			wtParam;		/* ID of Param representing work table */
+} WorkTableScan;
+
+
 /*
  * ==========
  * Join nodes