Initial implementation of lossy-tuple-bitmap data structures.

Not connected to anything useful yet ...

src/backend/nodes/Makefile

@@ -4,7 +4,7 @@
 #    Makefile for backend/nodes
 #
 # IDENTIFICATION
-#    $PostgreSQL: pgsql/src/backend/nodes/Makefile,v 1.17 2004/08/02 01:30:42 tgl Exp $
+#    $PostgreSQL: pgsql/src/backend/nodes/Makefile,v 1.18 2005/04/17 22:24:02 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -12,7 +12,7 @@ subdir = src/backend/nodes
 top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
-OBJS = nodeFuncs.o nodes.o list.o bitmapset.o \
+OBJS = nodeFuncs.o nodes.o list.o bitmapset.o tidbitmap.o \
        copyfuncs.o equalfuncs.o makefuncs.o \
        outfuncs.o readfuncs.o print.o read.o params.o value.o
 

src/include/nodes/nodes.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/nodes/nodes.h,v 1.165 2005/04/06 16:34:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.166 2005/04/17 22:24:02 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -304,11 +304,16 @@ typedef enum NodeTag
 	T_FunctionParameter,
 
 	/*
-	 * TAGS FOR FUNCTION-CALL CONTEXT AND RESULTINFO NODES (see fmgr.h)
+	 * TAGS FOR RANDOM OTHER STUFF
+	 *
+	 * These are objects that aren't part of parse/plan/execute node tree
+	 * structures, but we give them NodeTags anyway for identification
+	 * purposes (usually because they are involved in APIs where we want
+	 * to pass multiple object types through the same pointer).
 	 */
 	T_TriggerData = 900,		/* in commands/trigger.h */
-	T_ReturnSetInfo				/* in nodes/execnodes.h */
-
+	T_ReturnSetInfo,			/* in nodes/execnodes.h */
+	T_TIDBitmap					/* in nodes/tidbitmap.h */
 } NodeTag;
 
 /*

src/include/nodes/tidbitmap.h

+/*-------------------------------------------------------------------------
+ *
+ * tidbitmap.h
+ *	  PostgreSQL tuple-id (TID) bitmap package
+ *
+ * This module provides bitmap data structures that are spiritually
+ * similar to Bitmapsets, but are specially adapted to store sets of
+ * tuple identifiers (TIDs), or ItemPointers.  In particular, the division
+ * of an ItemPointer into BlockNumber and OffsetNumber is catered for.
+ * Also, since we wish to be able to store very large tuple sets in
+ * memory with this data structure, we support "lossy" storage, in which
+ * we no longer remember individual tuple offsets on a page but only the
+ * fact that a particular page needs to be visited.
+ *
+ *
+ * Copyright (c) 2003-2005, PostgreSQL Global Development Group
+ *
+ * $PostgreSQL: pgsql/src/include/nodes/tidbitmap.h,v 1.1 2005/04/17 22:24:02 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef TIDBITMAP_H
+#define TIDBITMAP_H
+
+#include "storage/itemptr.h"
+
+
+/*
+ * Actual bitmap representation is private to tidbitmap.c.  Callers can
+ * do IsA(x, TIDBitmap) on it, but nothing else.
+ */
+typedef struct TIDBitmap TIDBitmap;
+
+/* Result structure for tbm_iterate */
+typedef struct
+{
+	BlockNumber	blockno;		/* page number containing tuples */
+	int			ntuples;		/* -1 indicates lossy result */
+	OffsetNumber offsets[1];	/* VARIABLE LENGTH ARRAY */
+} TBMIterateResult;				/* VARIABLE LENGTH STRUCT */
+
+/* function prototypes in nodes/tidbitmap.c */
+
+extern TIDBitmap *tbm_create(long maxbytes);
+extern void tbm_free(TIDBitmap *tbm);
+
+extern void tbm_add_tuples(TIDBitmap *tbm, const ItemPointer tids, int ntids);
+
+extern void tbm_union(TIDBitmap *a, const TIDBitmap *b);
+extern void tbm_intersect(TIDBitmap *a, const TIDBitmap *b);
+
+extern void tbm_begin_iterate(TIDBitmap *tbm);
+extern TBMIterateResult *tbm_iterate(TIDBitmap *tbm);
+
+#endif   /* TIDBITMAP_H */