Replace the parser's namespace tree (which formerly had the same

representation as the jointree) with two lists of RTEs, one showing
the RTEs accessible by qualified names, and the other showing the RTEs
accessible by unqualified names.  I think this is conceptually simpler
than what we did before, and it's sure a whole lot easier to search.
This seems to eliminate the parse-time bottleneck for deeply nested
JOIN structures that was exhibited by phil@vodafone.

1 files changed, 16 insertions, 8 deletions

diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index bfcf00fd47d..291282e0920 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.43 2005/04/28 21:47:18 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.44 2005/06/05 00:38:11 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,12 +27,19 @@
  * p_joinlist: list of join items (RangeTblRef and JoinExpr nodes) that
  * will become the fromlist of the query's top-level FromExpr node.
  *
- * p_namespace: list of join items that represents the current namespace
- * for table and column lookup.  This may be just a subset of the rtable +
- * joinlist, and/or may contain entries that are not yet added to the main
- * joinlist.  Note that an RTE that is present in p_namespace, but does not
- * have its inFromCl flag set, is accessible only with an explicit qualifier;
- * lookups of unqualified column names should ignore it.
+ * p_relnamespace: list of RTEs that represents the current namespace for
+ * table lookup, ie, those RTEs that are accessible by qualified names.
+ * This may be just a subset of the rtable + joinlist, and/or may contain
+ * entries that are not yet added to the main joinlist.
+ *
+ * p_varnamespace: list of RTEs that represents the current namespace for
+ * column lookup, ie, those RTEs that are accessible by unqualified names.
+ * This is different from p_relnamespace because a JOIN without an alias does
+ * not hide the contained tables (so they must still be in p_relnamespace)
+ * but it does hide their columns (unqualified references to the columns must
+ * refer to the JOIN, not the member tables).  Also, we put POSTQUEL-style
+ * implicit RTEs into p_relnamespace but not p_varnamespace, so that they
+ * do not affect the set of columns available for unqualified references.
  *
  * p_paramtypes: an array of p_numparams type OIDs for $n parameter symbols
  * (zeroth entry in array corresponds to $1).  If p_variableparams is true, the
@@ -49,7 +56,8 @@ typedef struct ParseState
 	List	   *p_rtable;		/* range table so far */
 	List	   *p_joinlist;		/* join items so far (will become FromExpr
 								 * node's fromlist) */
-	List	   *p_namespace;	/* current lookup namespace (join items) */
+	List	   *p_relnamespace;	/* current namespace for relations */
+	List	   *p_varnamespace;	/* current namespace for columns */
 	Oid		   *p_paramtypes;	/* OIDs of types for $n parameter symbols */
 	int			p_numparams;	/* allocated size of p_paramtypes[] */
 	int			p_next_resno;	/* next targetlist resno to assign */