Second phase of psort reconstruction project: add bookkeeping logic to

recycle storage within sort temp file on a block-by-block basis.  This
reduces peak disk usage to essentially just the volume of data being
sorted, whereas it had been about 4x the data volume before.

src/backend/utils/sort/Makefile

@@ -4,7 +4,7 @@
 #    Makefile for utils/sort
 #
 # IDENTIFICATION
-#    $Header: /cvsroot/pgsql/src/backend/utils/sort/Makefile,v 1.5 1998/04/06 00:27:37 momjian Exp $
+#    $Header: /cvsroot/pgsql/src/backend/utils/sort/Makefile,v 1.6 1999/10/16 19:49:27 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -13,7 +13,7 @@ include ../../../Makefile.global
 
 CFLAGS += -I../..
 
-OBJS = lselect.o psort.o
+OBJS = logtape.o lselect.o psort.o
 
 all: SUBSYS.o
 

src/include/storage/buffile.h

@@ -17,7 +17,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: buffile.h,v 1.1 1999/10/13 15:02:32 tgl Exp $
+ * $Id: buffile.h,v 1.2 1999/10/16 19:49:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -37,11 +37,12 @@ typedef struct BufFile BufFile;
 
 extern BufFile *BufFileCreateTemp(void);
 extern BufFile *BufFileCreate(File file);
-extern BufFile *BufFileReaccess(BufFile *file);
 extern void BufFileClose(BufFile *file);
 extern size_t BufFileRead(BufFile *file, void *ptr, size_t size);
 extern size_t BufFileWrite(BufFile *file, void *ptr, size_t size);
 extern int BufFileSeek(BufFile *file, int fileno, long offset, int whence);
 extern void BufFileTell(BufFile *file, int *fileno, long *offset);
+extern int BufFileSeekBlock(BufFile *file, long blknum);
+extern long BufFileTellBlock(BufFile *file);
 
 #endif	 /* BUFFILE_H */

src/include/utils/logtape.h

+/*-------------------------------------------------------------------------
+ *
+ * logtape.h
+ *	  Management of "logical tapes" within temporary files.
+ *
+ * See logtape.c for explanations.
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: logtape.h,v 1.1 1999/10/16 19:49:28 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef LOGTAPE_H
+#define LOGTAPE_H
+
+/* LogicalTapeSet is an opaque type whose details are not known outside logtape.c. */
+
+typedef struct LogicalTapeSet LogicalTapeSet;
+
+/*
+ * prototypes for functions in logtape.c
+ */
+
+extern LogicalTapeSet *LogicalTapeSetCreate(int ntapes);
+extern void LogicalTapeSetClose(LogicalTapeSet *lts);
+extern size_t LogicalTapeRead(LogicalTapeSet *lts, int tapenum,
+							  void *ptr, size_t size);
+extern void LogicalTapeWrite(LogicalTapeSet *lts, int tapenum,
+							 void *ptr, size_t size);
+extern void LogicalTapeRewind(LogicalTapeSet *lts, int tapenum, bool forWrite);
+extern void LogicalTapeFreeze(LogicalTapeSet *lts, int tapenum);
+extern bool LogicalTapeBackspace(LogicalTapeSet *lts, int tapenum,
+								 size_t size);
+extern bool LogicalTapeSeek(LogicalTapeSet *lts, int tapenum,
+							long blocknum, int offset);
+extern void LogicalTapeTell(LogicalTapeSet *lts, int tapenum,
+							long *blocknum, int *offset);
+
+#endif	 /* LOGTAPE_H */

src/include/utils/psort.h

 /*-------------------------------------------------------------------------
  *
  * psort.h
- *
- *
+ *	  Polyphase merge sort.
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: psort.h,v 1.22 1999/10/13 15:02:28 tgl Exp $
+ * $Id: psort.h,v 1.23 1999/10/16 19:49:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef PSORT_H
 #define PSORT_H
 
-#include "access/relscan.h"
+#include "access/htup.h"
+#include "access/skey.h"
 #include "nodes/plannodes.h"
-#include "storage/buffile.h"
-#include "utils/lselect.h"
-
-#define MAXTAPES		7		/* See Knuth Fig. 70, p273 */
-
-struct tape
-{
-	int			tp_dummy;		/* (D) */
-	int			tp_fib;			/* (A) */
-	BufFile    *tp_file;		/* (TAPE) */
-	struct tape *tp_prev;
-};
-
-struct cmplist
-{
-	int			cp_attn;		/* attribute number */
-	int			cp_num;			/* comparison function code */
-	int			cp_rev;			/* invert comparison flag */
-	struct cmplist *cp_next;	/* next in chain */
-};
-
-/* This structure preserves the state of psort between calls from different
- * nodes to its interface functions. Basically, it includes all of the global
- * variables in psort. In case you were wondering, pointers to these structures
- * are included in Sort node structures.						-Rex 2.6.1995
- */
-typedef struct Psortstate
-{
-	LeftistContextData treeContext;
-
-	int			TapeRange;
-	int			Level;
-	int			TotalDummy;
-	struct tape Tape[MAXTAPES];
-
-	int			BytesRead;
-	int			BytesWritten;
-	int			tupcount;
-
-	struct leftist *Tuples;
-
-	BufFile    *psort_grab_file;
-	long		psort_current;	/* array index (only used if not tape) */
-	int			psort_saved_fileno;	/* upper bits of psort_saved, if tape */
-	long		psort_saved;	/* could be file offset, or array index */
-	bool		using_tape_files;
-	bool		all_fetched;	/* this is for cursors */
-
-	HeapTuple  *memtuples;
-} Psortstate;
-
-#ifdef	EBUG
-#include "storage/buf.h"
-#include "storage/bufmgr.h"
-
-#define PDEBUG(PROC, S1)\
-elog(DEBUG, "%s:%d>> PROC: %s.", __FILE__, __LINE__, S1)
-
-#define PDEBUG2(PROC, S1, D1)\
-elog(DEBUG, "%s:%d>> PROC: %s %d.", __FILE__, __LINE__, S1, D1)
-
-#define PDEBUG4(PROC, S1, D1, S2, D2)\
-elog(DEBUG, "%s:%d>> PROC: %s %d, %s %d.", __FILE__, __LINE__, S1, D1, S2, D2)
-
-#define VDEBUG(VAR, FMT)\
-elog(DEBUG, "%s:%d>> VAR =FMT", __FILE__, __LINE__, VAR)
-
-#define ASSERT(EXPR, STR)\
-if (!(EXPR)) elog(FATAL, "%s:%d>> %s", __FILE__, __LINE__, STR)
-
-#define TRACE(VAL, CODE)\
-if (1) CODE; else
-
-#else
-#define PDEBUG(MSG)
-#define VDEBUG(VAR, FMT)
-#define ASSERT(EXPR, MSG)
-#define TRACE(VAL, CODE)
-#endif
 
-/* psort.c */
 extern bool psort_begin(Sort *node, int nkeys, ScanKey key);
 extern HeapTuple psort_grabtuple(Sort *node, bool *should_free);
 extern void psort_markpos(Sort *node);