here it is as requested by Bruce.

I tested it restoring my database with > 100000 BLOBS, and dumping it out.
But unfortunatly I can not restore it back due to problems in pg_dump.

--
Sincerely Yours,
Denis Perchine

src/backend/catalog/Makefile

@@ -2,7 +2,7 @@
 #
 # Makefile for catalog
 #
-# $Header: /cvsroot/pgsql/src/backend/catalog/Makefile,v 1.28 2000/10/20 21:03:42 petere Exp $
+# $Header: /cvsroot/pgsql/src/backend/catalog/Makefile,v 1.29 2000/10/21 15:55:21 momjian Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -11,7 +11,8 @@ top_builddir = ../../..
 include $(top_builddir)/src/Makefile.global
 
 OBJS = catalog.o heap.o index.o indexing.o aclchk.o \
-       pg_aggregate.o pg_operator.o pg_proc.o pg_type.o
+       pg_aggregate.o pg_largeobject.o pg_operator.o pg_proc.o \
+       pg_type.o
 
 BKIFILES = global.bki template1.bki global.description template1.description
 
@@ -29,7 +30,7 @@ TEMPLATE1_BKI_SRCS := $(addprefix $(top_srcdir)/src/include/catalog/,\
 	pg_proc.h pg_type.h pg_attribute.h pg_class.h \
 	pg_inherits.h pg_index.h pg_statistic.h \
 	pg_operator.h pg_opclass.h pg_am.h pg_amop.h pg_amproc.h \
-	pg_language.h \
+	pg_language.h pg_largeobject.h \
 	pg_aggregate.h pg_ipl.h pg_inheritproc.h \
 	pg_rewrite.h pg_listener.h pg_description.h indexing.h \
     )

src/backend/catalog/indexing.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.69 2000/10/08 03:53:13 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.70 2000/10/21 15:55:21 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -51,6 +51,8 @@ char	   *Name_pg_inherits_indices[Num_pg_inherits_indices] =
 {InheritsRelidSeqnoIndex};
 char	   *Name_pg_language_indices[Num_pg_language_indices] =
 {LanguageOidIndex, LanguageNameIndex};
+char	   *Name_pg_largeobject_indices[Num_pg_largeobject_indices] =
+{LargeobjectLOIdIndex, LargeobjectLOIdPNIndex};
 char	   *Name_pg_listener_indices[Num_pg_listener_indices] =
 {ListenerPidRelnameIndex};
 char	   *Name_pg_opclass_indices[Num_pg_opclass_indices] =

src/backend/catalog/pg_largeobject.c

+/*-------------------------------------------------------------------------
+ *
+ * pg_largeobject.c
+ *	  routines to support manipulation of the pg_largeobject relation
+ *
+ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_largeobject.c,v 1.3 2000/10/21 15:55:21 momjian Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/genam.h"
+#include "access/heapam.h"
+#include "catalog/catname.h"
+#include "catalog/indexing.h"
+#include "catalog/pg_largeobject.h"
+#include "miscadmin.h"
+#include "utils/fmgroids.h"
+
+bytea *_byteain(const char *data, int32 size);
+
+bytea *_byteain(const char *data, int32 size) {
+	bytea	*result;
+
+	result = (bytea *)palloc(size + VARHDRSZ);
+	result->vl_len = size + VARHDRSZ;
+	if (size > 0)
+		memcpy(result->vl_dat, data, size);
+	
+	return result;
+}
+
+Oid LargeobjectCreate(Oid loid) {
+	Oid		retval;
+  	Relation        	pg_largeobject;
+	HeapTuple	ntup = (HeapTuple) palloc(sizeof(HeapTupleData));
+	Relation		idescs[Num_pg_largeobject_indices];
+	Datum		values[Natts_pg_largeobject];
+	char		nulls[Natts_pg_largeobject];
+	int		i;
+
+	for (i=0; i<Natts_pg_largeobject; i++) {
+		nulls[i] = ' ';
+		values[i] = (Datum)NULL;
+	}
+
+	i = 0;
+	values[i++] = ObjectIdGetDatum(loid);
+	values[i++] = Int32GetDatum(0);
+	values[i++] = (Datum) _byteain(NULL, 0);
+	
+	pg_largeobject = heap_openr(LargeobjectRelationName, RowExclusiveLock);
+	ntup = heap_formtuple(pg_largeobject->rd_att, values, nulls);
+	retval = heap_insert(pg_largeobject, ntup);
+
+	if (!IsIgnoringSystemIndexes()) {
+		CatalogOpenIndices(Num_pg_largeobject_indices, Name_pg_largeobject_indices, idescs);
+		CatalogIndexInsert(idescs, Num_pg_largeobject_indices, pg_largeobject, ntup);
+		CatalogCloseIndices(Num_pg_largeobject_indices, idescs);
+	}
+	
+	heap_close(pg_largeobject, RowExclusiveLock);
+	heap_freetuple(ntup);
+	
+	CommandCounterIncrement();
+
+	return retval;
+}
+
+void LargeobjectDrop(Oid loid) {
+	Relation	pg_largeobject;
+	Relation	pg_lo_id;
+	ScanKeyData	skey;
+	IndexScanDesc	sd = (IndexScanDesc) NULL;
+	RetrieveIndexResult	indexRes;
+	int	found = 0;
+
+	ScanKeyEntryInitialize(&skey,
+					    (bits16) 0x0,
+					    (AttrNumber) 1,
+					    (RegProcedure) F_OIDEQ,
+					    ObjectIdGetDatum(loid));
+
+	pg_largeobject = heap_openr(LargeobjectRelationName, RowShareLock);
+	pg_lo_id = index_openr(LargeobjectLOIdIndex);
+
+	sd = index_beginscan(pg_lo_id, false, 1, &skey);
+
+	while((indexRes = index_getnext(sd, ForwardScanDirection))) {
+		found++;
+		heap_delete(pg_largeobject, &indexRes->heap_iptr, NULL);
+		pfree(indexRes);
+	}
+
+	index_endscan(sd);
+
+	index_close(pg_lo_id);
+	heap_close(pg_largeobject, RowShareLock);
+	if (found == 0)
+		elog(ERROR, "LargeobjectDrop: large object %d not found", loid);
+}
+
+int LargeobjectFind(Oid loid) {
+	int	retval = 0;
+	Relation	pg_lo_id;
+	ScanKeyData	skey;
+	IndexScanDesc	sd = (IndexScanDesc) NULL;
+	RetrieveIndexResult	indexRes;
+
+	ScanKeyEntryInitialize(&skey,
+					    (bits16) 0x0,
+					    (AttrNumber) 1,
+					    (RegProcedure) F_OIDEQ,
+					    ObjectIdGetDatum(loid));
+
+	pg_lo_id = index_openr(LargeobjectLOIdIndex);
+
+	sd = index_beginscan(pg_lo_id, false, 1, &skey);
+
+	if ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+		retval = 1;
+		pfree(indexRes);
+	}
+
+	index_endscan(sd);
+
+	index_close(pg_lo_id);
+	return retval;
+}
+

src/backend/libpq/be-fsstubs.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/be-fsstubs.c,v 1.52 2000/10/08 03:53:13 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/be-fsstubs.c,v 1.53 2000/10/21 15:55:22 momjian Exp $
  *
  * NOTES
  *	  This should be moved to a more appropriate place.  It is here
@@ -267,7 +267,7 @@ lo_creat(PG_FUNCTION_ARGS)
 		PG_RETURN_OID(InvalidOid);
 	}
 
-	lobjId = RelationGetRelid(lobjDesc->heap_r);
+	lobjId = lobjDesc->id;
 
 	inv_close(lobjDesc);
 
@@ -512,8 +512,10 @@ lo_commit(bool isCommit)
 	{
 		if (cookies[i] != NULL)
 		{
+/*
 			if (isCommit)
 				inv_cleanindex(cookies[i]);
+*/
 			cookies[i] = NULL;
 		}
 	}

src/backend/storage/large_object/inv_api.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.76 2000/10/08 03:53:14 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/storage/large_object/inv_api.c,v 1.77 2000/10/21 15:55:24 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -22,58 +22,34 @@
 #include "access/genam.h"
 #include "access/heapam.h"
 #include "access/nbtree.h"
+#include "access/htup.h"
 #include "catalog/catalog.h"
+#include "catalog/catname.h"
 #include "catalog/heap.h"
 #include "catalog/index.h"
+#include "catalog/indexing.h"
 #include "catalog/pg_opclass.h"
+#include "catalog/pg_largeobject.h"
 #include "catalog/pg_type.h"
 #include "libpq/libpq-fs.h"
 #include "miscadmin.h"
 #include "storage/large_object.h"
 #include "storage/smgr.h"
 #include "utils/fmgroids.h"
-#include "utils/relcache.h"
+#include "utils/builtins.h"
 
-/*
- *	Warning, Will Robinson...  In order to pack data into an inversion
- *	file as densely as possible, we violate the class abstraction here.
- *	When we're appending a new tuple to the end of the table, we check
- *	the last page to see how much data we can put on it.  If it's more
- *	than IMINBLK, we write enough to fill the page.  This limits external
- *	fragmentation.	In no case can we write more than IMAXBLK, since
- *	the 8K postgres page size less overhead leaves only this much space
- *	for data.
- */
+#include <errno.h>
 
-/*
- *		In order to prevent buffer leak on transaction commit, large object
- *		scan index handling has been modified. Indexes are persistant inside
- *		a transaction but may be closed between two calls to this API (when
- *		transaction is committed while object is opened, or when no
- *		transaction is active). Scan indexes are thus now reinitialized using
- *		the object current offset. [PA]
- *
- *		Some cleanup has been also done for non freed memory.
- *
- *		For subsequent notes, [PA] is Pascal Andr <andre@via.ecp.fr>
- */
+#define	IBLKSIZE		(MaxTupleSize - MinHeapTupleBitmapSize - sizeof(int32) * 3)
 
-#define IFREESPC(p)		(PageGetFreeSpace(p) - \
-				 MAXALIGN(offsetof(HeapTupleHeaderData,t_bits)) - \
-				 MAXALIGN(sizeof(struct varlena) + sizeof(int32)) - \
-				 sizeof(double))
-#define IMAXBLK			8092
-#define IMINBLK			512
-
-/* non-export function prototypes */
-static HeapTuple inv_newtuple(LargeObjectDesc *obj_desc, Buffer buffer,
-			 Page page, char *dbuf, int nwrite);
-static void inv_fetchtup(LargeObjectDesc *obj_desc, HeapTuple tuple, Buffer *buffer);
-static int	inv_wrnew(LargeObjectDesc *obj_desc, char *buf, int nbytes);
-static int inv_wrold(LargeObjectDesc *obj_desc, char *dbuf, int nbytes,
-		  HeapTuple tuple, Buffer buffer);
-static void inv_indextup(LargeObjectDesc *obj_desc, HeapTuple tuple);
-static int	_inv_getsize(Relation hreln, TupleDesc hdesc, Relation ireln);
+/* Defined in backend/storage/catalog/large_object.c */
+bytea *_byteain(const char *data, int32 size);
+
+static int32 getbytealen(bytea *data) {
+	if (VARSIZE(data) < VARHDRSZ)
+		elog(ERROR, "getbytealen: VARSIZE(data) < VARHDRSZ. This is internal error.");
+  return (VARSIZE(data) - VARHDRSZ);
+}
 
 /*
  *	inv_create -- create a new large object.
@@ -84,18 +60,12 @@ static int	_inv_getsize(Relation hreln, TupleDesc hdesc, Relation ireln);
  *		Returns:
  *		  large object descriptor, appropriately filled in.
  */
+
 LargeObjectDesc *
 inv_create(int flags)
 {
+	int		file_oid;
 	LargeObjectDesc *retval;
-	Oid			file_oid;
-	Relation	r;
-	Relation	indr;
-	TupleDesc	tupdesc;
-	IndexInfo  *indexInfo;
-	Oid			classObjectId[1];
-	char		objname[NAMEDATALEN];
-	char		indname[NAMEDATALEN];
 	
 	/*
 	 * add one here since the pg_class tuple created will have the next
@@ -104,104 +74,25 @@ inv_create(int flags)
 	 */
 	file_oid = newoid() + 1;
 
-	/* come up with some table names */
-	sprintf(objname, "xinv%u", file_oid);
-	sprintf(indname, "xinx%u", file_oid);
-
-	if (RelnameFindRelid(objname) != InvalidOid)
-		elog(ERROR,
-		  "internal error: %s already exists -- cannot create large obj",
-			 objname);
-	if (RelnameFindRelid(indname) != InvalidOid)
-		elog(ERROR,
-		  "internal error: %s already exists -- cannot create large obj",
-			 indname);
-
-	/* this is pretty painful...  want a tuple descriptor */
-	tupdesc = CreateTemplateTupleDesc(2);
-	TupleDescInitEntry(tupdesc, (AttrNumber) 1,
-					   "olastbye",
-					   INT4OID,
-					   -1, 0, false);
-	TupleDescInitEntry(tupdesc, (AttrNumber) 2,
-					   "odata",
-					   BYTEAOID,
-					   -1, 0, false);
-
-	/*
-	 * First create the table to hold the inversion large object.  It will
-	 * be located on whatever storage manager the user requested.
-	 */
-
-	heap_create_with_catalog(objname, tupdesc, RELKIND_LOBJECT,
-							 false, false);
-
-	/* make the relation visible in this transaction */
-	CommandCounterIncrement();
-
-	/*--------------------
-	 * We hold AccessShareLock on any large object we have open
-	 * by inv_create or inv_open; it is released by inv_close.
-	 * Note this will not conflict with ExclusiveLock or ShareLock
-	 * that we acquire when actually reading/writing; it just prevents
-	 * deletion of the large object while we have it open.
-	 *--------------------
-	 */
-	r = heap_openr(objname, AccessShareLock);
-
-	/*
-	 * Now create a btree index on the relation's olastbyte attribute to
-	 * make seeks go faster.
-	 */
-	indexInfo = makeNode(IndexInfo);
-	indexInfo->ii_NumIndexAttrs = 1;
-	indexInfo->ii_NumKeyAttrs = 1;
-	indexInfo->ii_KeyAttrNumbers[0] = 1;
-	indexInfo->ii_Predicate = NULL;
-	indexInfo->ii_FuncOid = InvalidOid;
-	indexInfo->ii_Unique = false;
-
-	classObjectId[0] = INT4_OPS_OID;
-
-	index_create(objname, indname, indexInfo,
-				 BTREE_AM_OID, classObjectId,
-				 false, false, false);
-
-	/* make the index visible in this transaction */
-	CommandCounterIncrement();
-
-	indr = index_openr(indname);
-
-	if (!RelationIsValid(indr))
-	{
-		elog(ERROR, "cannot create index for large obj on %s under inversion",
-			 DatumGetCString(DirectFunctionCall1(smgrout,
-							 Int16GetDatum(DEFAULT_SMGR))));
-	}
+	if (LargeobjectFind(file_oid) == 1)
+		elog(ERROR, "inv_create: large object %d already exists. This is internal error.", file_oid);
 
 	retval = (LargeObjectDesc *) palloc(sizeof(LargeObjectDesc));
 
-	retval->heap_r = r;
-	retval->index_r = indr;
-	retval->iscan = (IndexScanDesc) NULL;
-	retval->hdesc = RelationGetDescr(r);
-	retval->idesc = RelationGetDescr(indr);
-	retval->offset = retval->lowbyte = retval->highbyte = 0;
-	ItemPointerSetInvalid(&(retval->htid));
-	retval->flags = 0;
-
-	if (flags & INV_WRITE)
-	{
-		LockRelation(r, ExclusiveLock);
+	if (flags & INV_WRITE) {
 		retval->flags = IFS_WRLOCK | IFS_RDLOCK;
-	}
-	else if (flags & INV_READ)
-	{
-		LockRelation(r, ShareLock);
+		retval->heap_r = heap_openr(LargeobjectRelationName, RowExclusiveLock);
+	} else if (flags & INV_READ) {
 		retval->flags = IFS_RDLOCK;
-	}
-	retval->flags |= IFS_ATEOF;	/* since we know the object is empty */
+		retval->heap_r = heap_openr(LargeobjectRelationName, AccessShareLock);
+	} else
+		elog(ERROR, "inv_create: invalid flags: %d", flags);
 
+	retval->flags |= IFS_ATEOF;
+	retval->index_r = index_openr(LargeobjectLOIdPNIndex);
+	retval->offset = 0;
+	retval->id = file_oid;
+	(void)LargeobjectCreate(file_oid);
 	return retval;
 }
 
@@ -209,46 +100,24 @@ LargeObjectDesc *
 inv_open(Oid lobjId, int flags)
 {
 	LargeObjectDesc *retval;
-	Relation	r;
-	char	   *indname;
-	Relation	indrel;
-
-	r = heap_open(lobjId, AccessShareLock);
 
-	indname = pstrdup(RelationGetRelationName(r));
-
-	/*
-	 * hack hack hack...  we know that the fourth character of the
-	 * relation name is a 'v', and that the fourth character of the index
-	 * name is an 'x', and that they're otherwise identical.
-	 */
-	indname[3] = 'x';
-	indrel = index_openr(indname);
+	if (LargeobjectFind(lobjId) == 0)
+		elog(ERROR, "inv_open: large object %d not found", lobjId);
 	
-	if (!RelationIsValid(indrel))
-		return (LargeObjectDesc *) NULL;
+	retval = (LargeObjectDesc *)palloc(sizeof(LargeObjectDesc));
 
-	retval = (LargeObjectDesc *) palloc(sizeof(LargeObjectDesc));
-
-	retval->heap_r = r;
-	retval->index_r = indrel;
-	retval->iscan = (IndexScanDesc) NULL;
-	retval->hdesc = RelationGetDescr(r);
-	retval->idesc = RelationGetDescr(indrel);
-	retval->offset = retval->lowbyte = retval->highbyte = 0;
-	ItemPointerSetInvalid(&(retval->htid));
-	retval->flags = 0;
-
-	if (flags & INV_WRITE)
-	{
-		LockRelation(r, ExclusiveLock);
+	if (flags & INV_WRITE) {
 		retval->flags = IFS_WRLOCK | IFS_RDLOCK;
-	}
-	else if (flags & INV_READ)
-	{
-		LockRelation(r, ShareLock);
+		retval->heap_r = heap_openr(LargeobjectRelationName, RowExclusiveLock);
+	} else if (flags & INV_READ) {
 		retval->flags = IFS_RDLOCK;
-	}
+		retval->heap_r = heap_openr(LargeobjectRelationName, AccessShareLock);
+	} else
+		elog(ERROR, "inv_open: invalid flags: %d", flags);
+
+	retval->index_r = index_openr(LargeobjectLOIdPNIndex);
+	retval->offset = 0;
+	retval->id = lobjId;
 
 	return retval;
 }
@@ -261,15 +130,11 @@ inv_close(LargeObjectDesc *obj_desc)
 {
 	Assert(PointerIsValid(obj_desc));
 
-	if (obj_desc->iscan != (IndexScanDesc) NULL)
-	{
-		index_endscan(obj_desc->iscan);
-		obj_desc->iscan = NULL;
-	}
-
-	index_close(obj_desc->index_r);
+	if (obj_desc->flags & IFS_WRLOCK)
+		heap_close(obj_desc->heap_r, RowExclusiveLock);
+	else if (obj_desc->flags & IFS_RDLOCK)
 		heap_close(obj_desc->heap_r, AccessShareLock);
-
+	index_close(obj_desc->index_r);
 	pfree(obj_desc);
 }
 
@@ -281,24 +146,7 @@ inv_close(LargeObjectDesc *obj_desc)
 int
 inv_drop(Oid lobjId)
 {
-	Relation	r;
-
-	r = RelationIdGetRelation(lobjId);
-	if (!RelationIsValid(r))
-		return -1;
-
-	if (r->rd_rel->relkind != RELKIND_LOBJECT)
-	{
-		/* drop relcache refcount from RelationIdGetRelation */
-		RelationDecrementReferenceCount(r);
-		return -1;
-	}
-
-	/*
-	 * Since heap_drop_with_catalog will destroy the relcache entry,
-	 * there's no need to drop the refcount in this path.
-	 */
-	heap_drop_with_catalog(RelationGetRelationName(r), false);
+	LargeobjectDrop(lobjId);
 	return 1;
 }
 
@@ -364,71 +212,75 @@ inv_stat(LargeObjectDesc *obj_desc, struct pgstat * stbuf)
 
 #endif
 
-int
-inv_seek(LargeObjectDesc *obj_desc, int offset, int whence)
-{
-	int			oldOffset;
-	Datum		d;
+static uint32 inv_getsize(LargeObjectDesc *obj_desc) {
+	uint32			found = 0;
+	uint32			lastbyte = 0;
 	ScanKeyData		skey;
+	IndexScanDesc		sd = (IndexScanDesc) NULL;
+	RetrieveIndexResult	indexRes;
+	HeapTupleData		tuple;
+	Buffer			buffer;
+	Form_pg_largeobject	data;
 
 	Assert(PointerIsValid(obj_desc));
 
-	if (whence == SEEK_CUR)
-	{
-		offset += obj_desc->offset;		/* calculate absolute position */
-	}
-	else if (whence == SEEK_END)
-	{
-		/* need read lock for getsize */
-		if (!(obj_desc->flags & IFS_RDLOCK))
-		{
-			LockRelation(obj_desc->heap_r, ShareLock);
-			obj_desc->flags |= IFS_RDLOCK;
-		}
-		offset += _inv_getsize(obj_desc->heap_r,
-							   obj_desc->hdesc,
-							   obj_desc->index_r);
+	ScanKeyEntryInitialize(&skey,
+					    (bits16) 0x0,
+					    (AttrNumber) 1,
+					    (RegProcedure) F_OIDEQ,
+					    ObjectIdGetDatum(obj_desc->id));
+
+	sd = index_beginscan(obj_desc->index_r, true, 1, &skey);
+	tuple.t_datamcxt = CurrentMemoryContext;
+	tuple.t_data = NULL;
+	while ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+		tuple.t_self = indexRes->heap_iptr;
+		heap_fetch(obj_desc->heap_r, SnapshotNow, &tuple, &buffer);
+		pfree(indexRes);
+		if (tuple.t_data == NULL)
+			continue;
+		found++;
+		data = (Form_pg_largeobject) GETSTRUCT(&tuple);
+		lastbyte = data->pageno * IBLKSIZE + getbytealen(&(data->data));
+		ReleaseBuffer(buffer);
+		break;
 	}
-	/* now we can assume that the operation is SEEK_SET */
 	
-	/*
-	 * Whenever we do a seek, we turn off the EOF flag bit to force
-	 * ourselves to check for real on the next read.
-	 */
+	index_endscan(sd);
 
-	obj_desc->flags &= ~IFS_ATEOF;
-	oldOffset = obj_desc->offset;
-	obj_desc->offset = offset;
+	if (found == 0)
+		elog(ERROR, "inv_getsize: large object %d not found", obj_desc->id);
+	return lastbyte;
+}
 
-	/* try to avoid doing any work, if we can manage it */
-	if (offset >= obj_desc->lowbyte
-		&& offset <= obj_desc->highbyte
-		&& oldOffset <= obj_desc->highbyte
-		&& obj_desc->iscan != (IndexScanDesc) NULL)
-		return offset;
+int
+inv_seek(LargeObjectDesc *obj_desc, int offset, int whence)
+{
+	Assert(PointerIsValid(obj_desc));
 
-	/*
-	 * To do a seek on an inversion file, we start an index scan that will
-	 * bring us to the right place.  Each tuple in an inversion file
-	 * stores the offset of the last byte that appears on it, and we have
-	 * an index on this.
-	 */
-	if (obj_desc->iscan != (IndexScanDesc) NULL)
+	switch (whence) {
+		case SEEK_SET:
+			if (offset < 0)
+				elog(ERROR, "inv_seek: invalid offset: %d", offset);
+			obj_desc->offset = offset;
+			break;
+		case SEEK_CUR:
+			if ((obj_desc->offset + offset) < 0)
+				elog(ERROR, "inv_seek: invalid offset: %d", offset);
+			obj_desc->offset += offset;
+			break;
+		case SEEK_END:
 			{
-		d = Int32GetDatum(offset);
-		btmovescan(obj_desc->iscan, d);
+				int4 size = inv_getsize(obj_desc);
+				if (offset > size)
+					elog(ERROR, "inv_seek: invalid offset");
+				obj_desc->offset = size - offset;
 			}
-	else
-	{
-		ScanKeyEntryInitialize(&skey, 0x0, 1, F_INT4GE,
-							   Int32GetDatum(offset));
-
-		obj_desc->iscan = index_beginscan(obj_desc->index_r,
-										  (bool) 0, (uint16) 1,
-										  &skey);
+			break;
+		default:
+			elog(ERROR, "inv_seek: invalid whence: %d", whence);
 	}
-
-	return offset;
+	return obj_desc->offset;
 }
 
 int
@@ -442,862 +294,259 @@ inv_tell(LargeObjectDesc *obj_desc)
 int
 inv_read(LargeObjectDesc *obj_desc, char *buf, int nbytes)
 {
+	uint32			nread = 0;
+	uint32			n;
+	uint32			off;
+	uint32			len;
+	uint32			found = 0;
+	uint32			pageno = obj_desc->offset / IBLKSIZE; 
+	ScanKeyData		skey[2];
+	IndexScanDesc		sd = (IndexScanDesc) NULL;
+	RetrieveIndexResult	indexRes;
 	HeapTupleData		tuple;
-	int			nread;
-	int			off;
-	int			ncopy;
-	Datum		d;
-	struct varlena *fsblock;
-	bool		isNull;
+	Buffer			buffer;
+	Form_pg_largeobject	data;
 
 	Assert(PointerIsValid(obj_desc));
 	Assert(buf != NULL);
 
-	/* if we're already at EOF, we don't need to do any work here */
-	if (obj_desc->flags & IFS_ATEOF)
-		return 0;
+	ScanKeyEntryInitialize(&skey[0],
+					    (bits16) 0x0,
+					    (AttrNumber) 1,
+					    (RegProcedure) F_OIDEQ,
+					    ObjectIdGetDatum(obj_desc->id));
 
-	/* make sure we obey two-phase locking */
-	if (!(obj_desc->flags & IFS_RDLOCK))
-	{
-		LockRelation(obj_desc->heap_r, ShareLock);
-		obj_desc->flags |= IFS_RDLOCK;
-	}
+	ScanKeyEntryInitialize(&skey[1],
+					    (bits16) 0x0,
+					    (AttrNumber) 2,
+					    (RegProcedure) F_INT4GE,
+					    Int32GetDatum(pageno));
 
-	nread = 0;
+	sd = index_beginscan(obj_desc->index_r, false, 2, skey);
+	tuple.t_datamcxt = CurrentMemoryContext;
+	tuple.t_data = NULL;
+	while ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+		tuple.t_self = indexRes->heap_iptr;
+		heap_fetch(obj_desc->heap_r, SnapshotNow, &tuple, &buffer);
+		pfree(indexRes);
 
-	/* fetch a block at a time */
-	while (nread < nbytes)
-	{
-		Buffer		buffer;
+		if (tuple.t_data == NULL)
+			continue;
 		
-		/* fetch an inversion file system block */
-		inv_fetchtup(obj_desc, &tuple, &buffer);
+		found++;
+		data = (Form_pg_largeobject) GETSTRUCT(&tuple);
+		if (data->pageno != pageno) {
+			ReleaseBuffer(buffer);
+			index_endscan(sd);
+			return 0;
+		}
 
-		if (tuple.t_data == NULL)
-		{
-			obj_desc->flags |= IFS_ATEOF;
+		len = getbytealen(&(data->data));
+		off = obj_desc->offset % IBLKSIZE;
+		if (off == len) {
+			ReleaseBuffer(buffer);
 			break;
 		}
-
-		/* copy the data from this block into the buffer */
-		d = heap_getattr(&tuple, 2, obj_desc->hdesc, &isNull);
-		fsblock = (struct varlena *) DatumGetPointer(d);
+		if (off > len) {
 			ReleaseBuffer(buffer);
+			index_endscan(sd);
+			return 0;
+		}
+		n = len - off;
 
-		/*
-		 * If block starts beyond current seek point, then we are looking
-		 * at a "hole" (unwritten area) in the object.  Return zeroes for
-		 * the "hole".
-		 */
-		if (obj_desc->offset < obj_desc->lowbyte)
-		{
-			int		nzeroes = obj_desc->lowbyte - obj_desc->offset;
-
-			if (nzeroes > (nbytes - nread))
-				nzeroes = (nbytes - nread);
-			MemSet(buf, 0, nzeroes);
-			buf += nzeroes;
-			nread += nzeroes;
-			obj_desc->offset += nzeroes;
-			if (nread >= nbytes)
+		n = (n < (nbytes - nread)) ? n : (nbytes - nread);
+		memcpy(buf + nread, VARDATA(&(data->data)) + off, n);
+		nread += n;
+		obj_desc->offset += n;
+
+		ReleaseBuffer(buffer);
+		pageno++;
+		if (nread == nbytes)
 			break;
 	}
 
-		off = obj_desc->offset - obj_desc->lowbyte;
-		ncopy = obj_desc->highbyte - obj_desc->offset + 1;
-		if (ncopy > (nbytes - nread))
-			ncopy = (nbytes - nread);
-		memmove(buf, &(fsblock->vl_dat[off]), ncopy);
+	index_endscan(sd);
 
-		/* move pointers past the amount we just read */
-		buf += ncopy;
-		nread += ncopy;
-		obj_desc->offset += ncopy;
-	}
+	if (found == 0)
+		return 0;
 
 	return nread;
 }
 
-int
-inv_write(LargeObjectDesc *obj_desc, char *buf, int nbytes)
-{
+static int inv_write_existing(LargeObjectDesc *obj_desc, char *buf, int nbytes, int *found) {
+	uint32			n = 0;
+	uint32			off;
+	uint32			len;
+	int			i;
 	HeapTupleData		tuple;
-	int			nwritten;
-	int			tuplen;
+	HeapTuple		newtup;
+	Buffer			buffer;
+	Form_pg_largeobject	data;
+	ScanKeyData		skey[2];
+	IndexScanDesc		sd = (IndexScanDesc) NULL;
+	RetrieveIndexResult	indexRes;
+	Relation		idescs[Num_pg_largeobject_indices];
+	Datum			values[Natts_pg_largeobject];
+	char			nulls[Natts_pg_largeobject];
+	char			replace[Natts_pg_largeobject];
 
 	Assert(PointerIsValid(obj_desc));
 	Assert(buf != NULL);
 
-	/*
-	 * Make sure we obey two-phase locking.  A write lock entitles you to
-	 * read the relation, as well.
-	 */
+	ScanKeyEntryInitialize(&skey[0],
+					    (bits16) 0,
+					    (AttrNumber) 1,
+					    (RegProcedure) F_OIDEQ,
+					    ObjectIdGetDatum(obj_desc->id));
 
-	if (!(obj_desc->flags & IFS_WRLOCK))
-	{
-		LockRelation(obj_desc->heap_r, ExclusiveLock);
-		obj_desc->flags |= (IFS_WRLOCK | IFS_RDLOCK);
-	}
-
-	nwritten = 0;
+	ScanKeyEntryInitialize(&skey[1],
+					    (bits16) 0x0,
+					    (AttrNumber) 2,
+					    (RegProcedure) F_INT4EQ,
+					    Int32GetDatum(obj_desc->offset / IBLKSIZE));
 
-	/* write a block at a time */
-	while (nwritten < nbytes)
-	{
-		Buffer		buffer;
-
-		/*
-		 * Fetch the current inversion file system block.  We can skip
-		 * the work if we already know we are at EOF.
-		 */
-
-		if (obj_desc->flags & IFS_ATEOF)
+	CommandCounterIncrement();
+	sd = index_beginscan(obj_desc->index_r, false, 2, skey);
+	tuple.t_datamcxt = CurrentMemoryContext;
 	tuple.t_data = NULL;
-		else
-			inv_fetchtup(obj_desc, &tuple, &buffer);
-
-		/* either append or replace a block, as required */
-		if (tuple.t_data == NULL)
-			tuplen = inv_wrnew(obj_desc, buf, nbytes - nwritten);
-		else
-		{
-			if (obj_desc->offset > obj_desc->highbyte)
-			{
-				tuplen = inv_wrnew(obj_desc, buf, nbytes - nwritten);
-				ReleaseBuffer(buffer);
-			}
-			else
-				tuplen = inv_wrold(obj_desc, buf, nbytes - nwritten, &tuple, buffer);
-
-			/*
-			 * inv_wrold() has already issued WriteBuffer() which has
-			 * decremented local reference counter (LocalRefCount). So we
-			 * should not call ReleaseBuffer() here. -- Tatsuo 99/2/4
-			 */
-		}
-
-		/* move pointers past the amount we just wrote */
-		buf += tuplen;
-		nwritten += tuplen;
-		obj_desc->offset += tuplen;
-	}
-
-	/* that's it */
-	return nwritten;
-}
-
-/*
- * inv_cleanindex
- *		 Clean opened indexes for large objects, and clears current result.
- *		 This is necessary on transaction commit in order to prevent buffer
- *		 leak.
- *		 This function must be called for each opened large object.
- *		 [ PA, 7/17/98 ]
- */
-void
-inv_cleanindex(LargeObjectDesc *obj_desc)
-{
-	Assert(PointerIsValid(obj_desc));
-
-	if (obj_desc->iscan == (IndexScanDesc) NULL)
-		return;
-
-	index_endscan(obj_desc->iscan);
-	obj_desc->iscan = (IndexScanDesc) NULL;
-
-	ItemPointerSetInvalid(&(obj_desc->htid));
-}
-
-/*
- *	inv_fetchtup -- Fetch an inversion file system block.
- *
- *		This routine finds the file system block containing the offset
- *		recorded in the obj_desc structure.  Later, we need to think about
- *		the effects of non-functional updates (can you rewrite the same
- *		block twice in a single transaction?), but for now, we won't bother.
- *
- *		Parameters:
- *				obj_desc -- the object descriptor.
- *				bufP -- pointer to a buffer in the buffer cache; caller
- *						must free this.
- *
- *		Returns:
- *				A heap tuple containing the desired block, or NULL if no
- *				such tuple exists.
- */
-static void
-inv_fetchtup(LargeObjectDesc *obj_desc, HeapTuple tuple, Buffer *buffer)
-{
-	RetrieveIndexResult res;
-	Datum		d;
-	int			firstbyte,
-				lastbyte;
-	struct varlena *fsblock;
-	bool		isNull;
-
-	/*
-	 * If we've exhausted the current block, we need to get the next one.
-	 * When we support time travel and non-functional updates, we will
-	 * need to loop over the blocks, rather than just have an 'if', in
-	 * order to find the one we're really interested in.
-	 */
-
-	if (obj_desc->offset > obj_desc->highbyte
-		|| obj_desc->offset < obj_desc->lowbyte
-		|| !ItemPointerIsValid(&(obj_desc->htid)))
-	{
-		ScanKeyData skey;
-
-		ScanKeyEntryInitialize(&skey, 0x0, 1, F_INT4GE,
-							   Int32GetDatum(obj_desc->offset));
-
-		/* initialize scan key if not done */
-		if (obj_desc->iscan == (IndexScanDesc) NULL)
-		{
-
-			/*
-			 * As scan index may be prematurely closed (on commit), we
-			 * must use object current offset (was 0) to reinitialize the
-			 * entry [ PA ].
-			 */
-			obj_desc->iscan = index_beginscan(obj_desc->index_r,
-											  (bool) 0, (uint16) 1,
-											  &skey);
-		}
-		else
-			index_rescan(obj_desc->iscan, false, &skey);
-
-		do
-		{
-			res = index_getnext(obj_desc->iscan, ForwardScanDirection);
-
-			if (res == (RetrieveIndexResult) NULL)
-			{
-				ItemPointerSetInvalid(&(obj_desc->htid));
-				tuple->t_datamcxt = NULL;
-				tuple->t_data = NULL;
-				return;
-			}
-
-			/*
-			 * For time travel, we need to use the actual time qual here,
-			 * rather that NowTimeQual.  We currently have no way to pass
-			 * a time qual in.
-			 *
-			 * This is now valid for snapshot !!! And should be fixed in some
-			 * way...	- vadim 07/28/98
-			 *
-			 */
-			tuple->t_self = res->heap_iptr;
-			heap_fetch(obj_desc->heap_r, SnapshotNow, tuple, buffer);
-			pfree(res);
-		} while (tuple->t_data == NULL);
-
-		/* remember this tid -- we may need it for later reads/writes */
-		ItemPointerCopy(&(tuple->t_self), &obj_desc->htid);
-	}
-	else
-	{
-		tuple->t_self = obj_desc->htid;
-		heap_fetch(obj_desc->heap_r, SnapshotNow, tuple, buffer);
-		if (tuple->t_data == NULL)
-			elog(ERROR, "inv_fetchtup: heap_fetch failed");
+	while ((indexRes = index_getnext(sd, ForwardScanDirection))) {
+		tuple.t_self = indexRes->heap_iptr;
+		heap_fetch(obj_desc->heap_r, SnapshotNow, &tuple, &buffer);
+		pfree(indexRes);
+		if (tuple.t_data != NULL)
+			break;
 	}
 
-	/*
-	 * By here, we have the heap tuple we're interested in.  We cache the
-	 * upper and lower bounds for this block in the object descriptor and
-	 * return the tuple.
-	 */
-
-	d = heap_getattr(tuple, 1, obj_desc->hdesc, &isNull);
-	lastbyte = (int32) DatumGetInt32(d);
-	d = heap_getattr(tuple, 2, obj_desc->hdesc, &isNull);
-	fsblock = (struct varlena *) DatumGetPointer(d);
-
-	/*
-	 * order of + and - is important -- these are unsigned quantites near
-	 * 0
-	 */
-	firstbyte = (lastbyte + 1 + sizeof(fsblock->vl_len)) - fsblock->vl_len;
-
-	obj_desc->lowbyte = firstbyte;
-	obj_desc->highbyte = lastbyte;
-
-	return;
-}
-
-/*
- *	inv_wrnew() -- append a new filesystem block tuple to the inversion
- *					file.
- *
- *		In response to an inv_write, we append one or more file system
- *		blocks to the class containing the large object.  We violate the
- *		class abstraction here in order to pack things as densely as we
- *		are able.  We examine the last page in the relation, and write
- *		just enough to fill it, assuming that it has above a certain
- *		threshold of space available.  If the space available is less than
- *		the threshold, we allocate a new page by writing a big tuple.
- *
- *		By the time we get here, we know all the parameters passed in
- *		are valid, and that we hold the appropriate lock on the heap
- *		relation.
- *
- *		Parameters:
- *				obj_desc: large object descriptor for which to append block.
- *				buf: buffer containing data to write.
- *				nbytes: amount to write
- *
- *		Returns:
- *				number of bytes actually written to the new tuple.
- */
-static int
-inv_wrnew(LargeObjectDesc *obj_desc, char *buf, int nbytes)
-{
-	Relation	hr;
-	HeapTuple	ntup;
-	Buffer		buffer;
-	Page		page;
-	int			nblocks;
-	int			nwritten;
-
-	hr = obj_desc->heap_r;
-
-	/*
-	 * Get the last block in the relation.	If there's no data in the
-	 * relation at all, then we just get a new block.  Otherwise, we check
-	 * the last block to see whether it has room to accept some or all of
-	 * the data that the user wants to write.  If it doesn't, then we
-	 * allocate a new block.
-	 */
-
-	nblocks = RelationGetNumberOfBlocks(hr);
-
-	if (nblocks > 0)
-	{
-		buffer = ReadBuffer(hr, nblocks - 1);
-		page = BufferGetPage(buffer);
-	}
-	else
-	{
-		buffer = ReadBuffer(hr, P_NEW);
-		page = BufferGetPage(buffer);
-		PageInit(page, BufferGetPageSize(buffer), 0);
-	}
+	index_endscan(sd);
+	if (tuple.t_data == NULL)
+		return 0;
 	
-	/*
-	 * If the last page is too small to hold all the data, and it's too
-	 * small to hold IMINBLK, then we allocate a new page.	If it will
-	 * hold at least IMINBLK, but less than all the data requested, then
-	 * we write IMINBLK here.  The caller is responsible for noticing that
-	 * less than the requested number of bytes were written, and calling
-	 * this routine again.
-	 */
+	(*found)++;
+	data = (Form_pg_largeobject) GETSTRUCT(&tuple);
+	off = obj_desc->offset % IBLKSIZE;
+	len = getbytealen(&(data->data));
 
-	nwritten = IFREESPC(page);
-	if (nwritten < nbytes)
-	{
-		if (nwritten < IMINBLK)
-		{
+	if (len > IBLKSIZE) {
 		ReleaseBuffer(buffer);
-			buffer = ReadBuffer(hr, P_NEW);
-			page = BufferGetPage(buffer);
-			PageInit(page, BufferGetPageSize(buffer), 0);
-			if (nbytes > IMAXBLK)
-				nwritten = IMAXBLK;
-			else
-				nwritten = nbytes;
-		}
+		elog(FATAL, "Internal error: len > IBLKSIZE");
 	}
-	else
-		nwritten = nbytes;
-
-	/*
-	 * Insert a new file system block tuple, index it, and write it out.
-	 */
 
-	ntup = inv_newtuple(obj_desc, buffer, page, buf, nwritten);
-	inv_indextup(obj_desc, ntup);
-	heap_freetuple(ntup);
-
-	/* new tuple is inserted */
-	WriteBuffer(buffer);
-
-	return nwritten;
-}
-
-static int
-inv_wrold(LargeObjectDesc *obj_desc,
-		  char *dbuf,
-		  int nbytes,
-		  HeapTuple tuple,
-		  Buffer buffer)
-{
-	Relation	hr;
-	HeapTuple	ntup;
-	Buffer		newbuf;
-	Page		page;
-	Page		newpage;
-	int			tupbytes;
-	Datum		d;
-	struct varlena *fsblock;
-	int			nwritten,
-				nblocks,
-				freespc;
-	bool		isNull;
-	int			keep_offset;
-	RetrieveIndexResult res;
-
-	/*
-	 * Since we're using a no-overwrite storage manager, the way we
-	 * overwrite blocks is to mark the old block invalid and append a new
-	 * block.  First mark the old block invalid.  This violates the tuple
-	 * abstraction.
-	 */
-
-	TransactionIdStore(GetCurrentTransactionId(), &(tuple->t_data->t_xmax));
-	tuple->t_data->t_cmax = GetCurrentCommandId();
-	tuple->t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID);
-
-	/*
-	 * If we're overwriting the entire block, we're lucky.	All we need to
-	 * do is to insert a new block.
-	 */
-
-	if (obj_desc->offset == obj_desc->lowbyte
-		&& obj_desc->lowbyte + nbytes >= obj_desc->highbyte)
-	{
-		WriteBuffer(buffer);
-		return inv_wrnew(obj_desc, dbuf, nbytes);
+	for (i=0; i<Natts_pg_largeobject; i++) {
+		nulls[i] = ' ';
+		replace[i] = ' ';
+		values[i] = (Datum)NULL;
 	}
 
-	/*
-	 * By here, we need to overwrite part of the data in the current
-	 * tuple.  In order to reduce the degree to which we fragment blocks,
-	 * we guarantee that no block will be broken up due to an overwrite.
-	 * This means that we need to allocate a tuple on a new page, if
-	 * there's not room for the replacement on this one.
-	 */
-
-	newbuf = buffer;
-	page = BufferGetPage(buffer);
-	newpage = BufferGetPage(newbuf);
-	hr = obj_desc->heap_r;
-	freespc = IFREESPC(page);
-	d = heap_getattr(tuple, 2, obj_desc->hdesc, &isNull);
-	fsblock = (struct varlena *) DatumGetPointer(d);
-	tupbytes = fsblock->vl_len - sizeof(fsblock->vl_len);
-
-	if (freespc < tupbytes)
+	i = 0;
 	{
+		char b[IBLKSIZE];
+		int4 rest = len - off;
 
-		/*
-		 * First see if there's enough space on the last page of the table
-		 * to put this tuple.
-		 */
-
-		nblocks = RelationGetNumberOfBlocks(hr);
+		memset(b, 0, IBLKSIZE); /* Can optimize later */
+		if ((off > 0) && (len > 0)) /* We start in the middle of the tuple */
+			memcpy(b, VARDATA(&(data->data)), (off > len) ? len : off);
 		
-		if (nblocks > 0)
-		{
-			newbuf = ReadBuffer(hr, nblocks - 1);
-			newpage = BufferGetPage(newbuf);
-		}
+		if ((nbytes <= rest) || (len == IBLKSIZE)) {
+			/* We will update inside existing tuple size */
+			if (nbytes < rest)
+				n = rest;
 	 		else
-		{
-			newbuf = ReadBuffer(hr, P_NEW);
-			newpage = BufferGetPage(newbuf);
-			PageInit(newpage, BufferGetPageSize(newbuf), 0);
+				n = nbytes;
+			memcpy(b + off, buf, n);
+			if (n < rest) /* There's a rest of the tuple left */
+				memcpy(b + off + n, VARDATA(&(data->data)) + off + n, rest - n);
+			/* Update data only */
+			replace[2] = 'r';
+			values[2] = (Datum) _byteain(b, len);
+		 } else {
+			/* We will extend tuple */
+			/* Do we fit into max tuple size */
+			if (nbytes <= (IBLKSIZE - off))
+				len = off + nbytes;
+			else
+				len = IBLKSIZE;
+			n = len - off;
+			memcpy(b + off, buf, n);
+			/* Update data */
+			replace[2] = 'r';
+			values[2] = (Datum) _byteain(b, len);
 		 }
 
-		freespc = IFREESPC(newpage);
+		newtup = heap_modifytuple(&tuple, obj_desc->heap_r,
+					  values, nulls, replace);
 
-		/*
-		 * If there's no room on the last page, allocate a new last page
-		 * for the table, and put it there.
-		 */
-
-		if (freespc < tupbytes)
-		{
-			ReleaseBuffer(newbuf);
-			newbuf = ReadBuffer(hr, P_NEW);
-			newpage = BufferGetPage(newbuf);
-			PageInit(newpage, BufferGetPageSize(newbuf), 0);
+		heap_update(obj_desc->heap_r, &newtup->t_self, newtup, NULL);
+		if (!IsIgnoringSystemIndexes()) {
+			CatalogOpenIndices(Num_pg_largeobject_indices, Name_pg_largeobject_indices, idescs);
+			CatalogIndexInsert(idescs, Num_pg_largeobject_indices, obj_desc->heap_r, newtup);
+			CatalogCloseIndices(Num_pg_largeobject_indices, idescs);
 		}
+		heap_freetuple(newtup);
 	}
+	ReleaseBuffer(buffer);
 	
-	nwritten = nbytes;
-	if (nwritten > obj_desc->highbyte - obj_desc->offset + 1)
-		nwritten = obj_desc->highbyte - obj_desc->offset + 1;
-	memmove(VARDATA(fsblock) + (obj_desc->offset - obj_desc->lowbyte),
-			dbuf, nwritten);
-
-	/*
-	 * we are rewriting the entire old block, therefore we reset offset to
-	 * the lowbyte of the original block before jumping into
-	 * inv_newtuple()
-	 */
-	keep_offset = obj_desc->offset;
-	obj_desc->offset = obj_desc->lowbyte;
-	ntup = inv_newtuple(obj_desc, newbuf, newpage, VARDATA(fsblock),
-						tupbytes);
-	/* after we are done, we restore to the true offset */
-	obj_desc->offset = keep_offset;
-
-	/*
-	 * By here, we have a page (newpage) that's guaranteed to have enough
-	 * space on it to put the new tuple.  Call inv_newtuple to do the
-	 * work.  Passing NULL as a buffer to inv_newtuple() keeps it from
-	 * copying any data into the new tuple.  When it returns, the tuple is
-	 * ready to receive data from the old tuple and the user's data
-	 * buffer.
-	 */
-/*
-	ntup = inv_newtuple(obj_desc, newbuf, newpage, (char *) NULL, tupbytes);
-	dptr = ((char *) ntup) + ntup->t_hoff -
-				(sizeof(HeapTupleData) - offsetof(HeapTupleData, t_bits)) +
-				sizeof(int4)
-				+ sizeof(fsblock->vl_len);
-
-	if (obj_desc->offset > obj_desc->lowbyte) {
-		memmove(dptr,
-				&(fsblock->vl_dat[0]),
-				obj_desc->offset - obj_desc->lowbyte);
-		dptr += obj_desc->offset - obj_desc->lowbyte;
-	}
-
-
-	nwritten = nbytes;
-	if (nwritten > obj_desc->highbyte - obj_desc->offset + 1)
-		nwritten = obj_desc->highbyte - obj_desc->offset + 1;
-
-	memmove(dptr, dbuf, nwritten);
-	dptr += nwritten;
-
-	if (obj_desc->offset + nwritten < obj_desc->highbyte + 1) {
-*/
-/*
-		loc = (obj_desc->highbyte - obj_desc->offset)
-				+ nwritten;
-		sz = obj_desc->highbyte - (obj_desc->lowbyte + loc);
-
-		what's going on here?? - jolly
-*/
-/*
-		sz = (obj_desc->highbyte + 1) - (obj_desc->offset + nwritten);
-		memmove(&(fsblock->vl_dat[0]), dptr, sz);
-	}
-*/
-
-
-	/* index the new tuple */
-	inv_indextup(obj_desc, ntup);
-	heap_freetuple(ntup);
-
-	/*
-	 * move the scandesc forward so we don't reread the newly inserted
-	 * tuple on the next index scan
-	 */
-	res = NULL;
-	if (obj_desc->iscan)
-		res = index_getnext(obj_desc->iscan, ForwardScanDirection);
-
-	if (res)
-		pfree(res);
-
-	/*
-	 * Okay, by here, a tuple for the new block is correctly placed,
-	 * indexed, and filled.  Write the changed pages out.
-	 */
-
-	WriteBuffer(buffer);
-	if (newbuf != buffer)
-		WriteBuffer(newbuf);
-
-	/* Tuple id is no longer valid */
-	ItemPointerSetInvalid(&(obj_desc->htid));
-
-	/* done */
-	return nwritten;
+	return n;
 }
 
-static HeapTuple
-inv_newtuple(LargeObjectDesc *obj_desc,
-			 Buffer buffer,
-			 Page page,
-			 char *dbuf,
-			 int nwrite)
-{
+static int inv_write_append(LargeObjectDesc *obj_desc, char *buf, int nbytes) {
 	HeapTuple	ntup = (HeapTuple) palloc(sizeof(HeapTupleData));
-	PageHeader	ph;
-	int			tupsize;
-	int			hoff;
-	Offset		lower;
-	Offset		upper;
-	ItemId		itemId;
-	OffsetNumber off;
-	OffsetNumber limit;
-	char	   *attptr;
-
-	/* compute tuple size -- no nulls */
-	hoff = offsetof(HeapTupleHeaderData, t_bits);
-	hoff = MAXALIGN(hoff);
-
-	/* add in olastbyte, varlena.vl_len, varlena.vl_dat */
-	tupsize = hoff + (2 * sizeof(int32)) + nwrite;
-	tupsize = MAXALIGN(tupsize);
-
-	/*
-	 * Allocate the tuple on the page, violating the page abstraction.
-	 * This code was swiped from PageAddItem().
-	 */
-
-	ph = (PageHeader) page;
-	limit = OffsetNumberNext(PageGetMaxOffsetNumber(page));
-
-	/* look for "recyclable" (unused & deallocated) ItemId */
-	for (off = FirstOffsetNumber; off < limit; off = OffsetNumberNext(off))
-	{
-		itemId = &ph->pd_linp[off - 1];
-		if ((((*itemId).lp_flags & LP_USED) == 0) &&
-			((*itemId).lp_len == 0))
-			break;
-	}
-
-	if (off > limit)
-		lower = (Offset) (((char *) (&ph->pd_linp[off])) - ((char *) page));
-	else if (off == limit)
-		lower = ph->pd_lower + sizeof(ItemIdData);
-	else
-		lower = ph->pd_lower;
-
-	upper = ph->pd_upper - tupsize;
-
-	itemId = &ph->pd_linp[off - 1];
-	(*itemId).lp_off = upper;
-	(*itemId).lp_len = tupsize;
-	(*itemId).lp_flags = LP_USED;
-	ph->pd_lower = lower;
-	ph->pd_upper = upper;
-
-	ntup->t_datamcxt = NULL;
-	ntup->t_data = (HeapTupleHeader) ((char *) page + upper);
-
-	/*
-	 * Tuple is now allocated on the page.	Next, fill in the tuple
-	 * header.	This block of code violates the tuple abstraction.
-	 */
-
-	ntup->t_len = tupsize;
-	ItemPointerSet(&ntup->t_self, BufferGetBlockNumber(buffer), off);
-	ntup->t_data->t_oid = newoid();
-	TransactionIdStore(GetCurrentTransactionId(), &(ntup->t_data->t_xmin));
-	ntup->t_data->t_cmin = GetCurrentCommandId();
-	StoreInvalidTransactionId(&(ntup->t_data->t_xmax));
-	ntup->t_data->t_cmax = 0;
-	ntup->t_data->t_infomask = HEAP_XMAX_INVALID;
-	ntup->t_data->t_natts = 2;
-	ntup->t_data->t_hoff = hoff;
-
-	/* if a NULL is passed in, avoid the calculations below */
-	if (dbuf == NULL)
-		return ntup;
-
-	/*
-	 * Finally, copy the user's data buffer into the tuple.  This violates
-	 * the tuple and class abstractions.
-	 */
-
-	attptr = ((char *) ntup->t_data) + hoff;
-	*((int32 *) attptr) = obj_desc->offset + nwrite - 1;
-	attptr += sizeof(int32);
-
-	/*
-	 * *  mer fixed disk layout of varlenas to get rid of the need for
-	 * this. *
-	 *
-	 * ((int32 *) attptr) = nwrite + sizeof(int32); *  attptr +=
-	 * sizeof(int32);
-	 */
-
-	*((int32 *) attptr) = nwrite + sizeof(int32);
-	attptr += sizeof(int32);
-
-	/*
-	 * If a data buffer was passed in, then copy the data from the buffer
-	 * to the tuple.  Some callers (eg, inv_wrold()) may not pass in a
-	 * buffer, since they have to copy part of the old tuple data and part
-	 * of the user's new data into the new tuple.
-	 */
-
-	if (dbuf != (char *) NULL)
-		memmove(attptr, dbuf, nwrite);
-
-	/* keep track of boundary of current tuple */
-	obj_desc->lowbyte = obj_desc->offset;
-	obj_desc->highbyte = obj_desc->offset + nwrite - 1;
-
-	/* new tuple is filled -- return it */
-	return ntup;
-}
-
-static void
-inv_indextup(LargeObjectDesc *obj_desc, HeapTuple tuple)
-{
-	InsertIndexResult res;
-	Datum		v[1];
-	char		n[1];
-
-	n[0] = ' ';
-	v[0] = Int32GetDatum(obj_desc->highbyte);
-	res = index_insert(obj_desc->index_r, &v[0], &n[0],
-					   &(tuple->t_self), obj_desc->heap_r);
-
-	if (res)
-		pfree(res);
-}
-
-#ifdef NOT_USED
-
-static void
-DumpPage(Page page, int blkno)
-{
-		ItemId			lp;
-		HeapTuple		tup;
-		int				flags, i, nline;
-		ItemPointerData pointerData;
-
-		printf("\t[subblock=%d]:lower=%d:upper=%d:special=%d\n", 0,
-				((PageHeader)page)->pd_lower, ((PageHeader)page)->pd_upper,
-				((PageHeader)page)->pd_special);
-
-		printf("\t:MaxOffsetNumber=%d\n",
-			   (int16) PageGetMaxOffsetNumber(page));
-
-		nline = (int16) PageGetMaxOffsetNumber(page);
-
-{
+	Relation		idescs[Num_pg_largeobject_indices];
+	Datum		values[Natts_pg_largeobject];
+	char		nulls[Natts_pg_largeobject];
 	int		i;
-		char	*cp;
-
-		i = PageGetSpecialSize(page);
-		cp = PageGetSpecialPointer(page);
-
-		printf("\t:SpecialData=");
+	uint32		len;
 	
-		while (i > 0) {
-				printf(" 0x%02x", *cp);
-				cp += 1;
-				i -= 1;
+	for (i=0; i<Natts_pg_largeobject; i++) {
+		nulls[i] = ' ';
+		values[i] = (Datum)NULL;
 	}
-		printf("\n");
-}
-		for (i = 0; i < nline; i++) {
-				lp = ((PageHeader)page)->pd_linp + i;
-				flags = (*lp).lp_flags;
-				ItemPointerSet(&pointerData, blkno, 1 + i);
-				printf("%s:off=%d:flags=0x%x:len=%d",
-						ItemPointerFormExternal(&pointerData), (*lp).lp_off,
-						flags, (*lp).lp_len);
-
-				if (flags & LP_USED) {
-						HeapTupleData	htdata;
-
-						printf(":USED");
-
-						memmove((char *) &htdata,
-								(char *) &((char *)page)[(*lp).lp_off],
-								sizeof(htdata));
-
-						tup = &htdata;
-
-						printf("\n\t:ctid=%s:oid=%d",
-								ItemPointerFormExternal(&tup->t_ctid),
-								tup->t_oid);
-						printf(":natts=%d:thoff=%d:",
-								tup->t_natts,
-								tup->t_hoff);
 
-						printf("\n\t:cmin=%u:",
-								tup->t_cmin);
+	i = 0;
+	values[i++] = ObjectIdGetDatum(obj_desc->id);
+	len = (nbytes > IBLKSIZE) ? IBLKSIZE : nbytes;
 		
-						printf("xmin=%u:", tup->t_xmin);
+	values[i++] = Int32GetDatum(obj_desc->offset / IBLKSIZE);
+	values[i++] = (Datum) _byteain(buf, len);
 	
-						printf("\n\t:cmax=%u:",
-								tup->t_cmax);
+	ntup = heap_formtuple(obj_desc->heap_r->rd_att, values, nulls);
+	heap_insert(obj_desc->heap_r, ntup);
 
-						printf("xmax=%u:\n", tup->t_xmax);
-
-				} else
-						putchar('\n');
+	if (!IsIgnoringSystemIndexes()) {
+		CatalogOpenIndices(Num_pg_largeobject_indices, Name_pg_largeobject_indices, idescs);
+		CatalogIndexInsert(idescs, Num_pg_largeobject_indices, obj_desc->heap_r, ntup);
+		CatalogCloseIndices(Num_pg_largeobject_indices, idescs);
 	}
-}
 	
-static char*
-ItemPointerFormExternal(ItemPointer pointer)
-{
-		static char		itemPointerString[32];
-
-		if (!ItemPointerIsValid(pointer)) {
-			memmove(itemPointerString, "<-,-,->", sizeof "<-,-,->");
-		} else {
-			sprintf(itemPointerString, "<%u,%u>",
-					ItemPointerGetBlockNumber(pointer),
-					ItemPointerGetOffsetNumber(pointer));
-		}
+	heap_freetuple(ntup);
 	
-		return itemPointerString;
+	return len;
 }
 	
-#endif
-
-static int
-_inv_getsize(Relation hreln, TupleDesc hdesc, Relation ireln)
-{
-	IndexScanDesc iscan;
-	RetrieveIndexResult res;
-	HeapTupleData tuple;
-	Datum		d;
-	long		size;
-	bool		isNull;
-	Buffer		buffer;
-
-	/* scan backwards from end */
-	iscan = index_beginscan(ireln, (bool) 1, 0, (ScanKey) NULL);
-
-	do
-	{
-		res = index_getnext(iscan, BackwardScanDirection);
-
-		/*
-		 * If there are no more index tuples, then the relation is empty,
-		 * so the file's size is zero.
-		 */
+static int inv_write_int(LargeObjectDesc *obj_desc, char *buf, int nbytes) {
+	int			nwritten = 0;
+	int			found = 0;
 	
-		if (res == (RetrieveIndexResult) NULL)
-		{
-			index_endscan(iscan);
+	if (nbytes == 0)
 		return 0;
-		}
 
-		/*
-		 * For time travel, we need to use the actual time qual here,
-		 * rather that NowTimeQual.  We currently have no way to pass a
-		 * time qual in.
-		 */
-		tuple.t_self = res->heap_iptr;
-		heap_fetch(hreln, SnapshotNow, &tuple, &buffer);
-		pfree(res);
-	} while (tuple.t_data == NULL);
+	nwritten = inv_write_existing(obj_desc, buf, nbytes, &found);
+	if (found > 0) {
+		obj_desc->offset += nwritten;
+		return nwritten;
+	}
+	/* Looks like we are beyond the end of the file */
+	nwritten = inv_write_append(obj_desc, buf, nbytes);
+	obj_desc->offset += nwritten;
+	return nwritten;
+}
 
-	/* don't need the index scan anymore */
-	index_endscan(iscan);
+static int count = 0;
 
-	/* get olastbyte attribute */
-	d = heap_getattr(&tuple, 1, hdesc, &isNull);
-	size = DatumGetInt32(d) + 1;
-	ReleaseBuffer(buffer);
+int
+inv_write(LargeObjectDesc *obj_desc, char *buf, int nbytes) {
+	int nwritten = 0;
+	while (nwritten < nbytes)
+		nwritten += inv_write_int(obj_desc, buf + nwritten, nbytes - nwritten);
 
-	return size;
+	return nwritten;
 }

src/bin/pg_dump/pg_dump.c

@@ -22,7 +22,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.170 2000/10/13 00:43:31 pjw Exp $
+ *	  $Header: /cvsroot/pgsql/src/bin/pg_dump/pg_dump.c,v 1.171 2000/10/21 15:55:26 momjian Exp $
  *
  * Modifications - 6/10/96 - dave@bensoft.com - version 1.13.dhb
  *
@@ -1104,7 +1104,7 @@ dumpBlobs(Archive *AH, char* junkOid, void *junkVal)
 		fprintf(stderr, "%s saving BLOBs\n", g_comment_start);
 
 	/* Cursor to get all BLOB tables */
-    appendPQExpBuffer(oidQry, "Declare blobOid Cursor for SELECT oid from pg_class where relkind = '%c'", RELKIND_LOBJECT);
+    appendPQExpBuffer(oidQry, "Declare blobOid Cursor for SELECT loid from pg_largeobject");
 
 	res = PQexec(g_conn, oidQry->data);
 	if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)

src/include/catalog/catname.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: catname.h,v 1.14 2000/10/08 03:53:15 momjian Exp $
+ * $Id: catname.h,v 1.15 2000/10/21 15:55:28 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -29,6 +29,7 @@
 #define  InheritsRelationName "pg_inherits"
 #define  InheritancePrecidenceListRelationName "pg_ipl"
 #define  LanguageRelationName "pg_language"
+#define  LargeobjectRelationName "pg_largeobject"
 #define  ListenerRelationName "pg_listener"
 #define  LogRelationName "pg_log"
 #define  OperatorClassRelationName "pg_opclass"

src/include/catalog/indexing.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: indexing.h,v 1.42 2000/10/08 03:53:15 momjian Exp $
+ * $Id: indexing.h,v 1.43 2000/10/21 15:55:28 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,6 +31,7 @@
 #define Num_pg_index_indices		2
 #define Num_pg_inherits_indices		1
 #define Num_pg_language_indices		2
+#define Num_pg_largeobject_indices		2
 #define Num_pg_listener_indices		1
 #define Num_pg_opclass_indices		2
 #define Num_pg_operator_indices		2
@@ -62,6 +63,8 @@
 #define InheritsRelidSeqnoIndex		"pg_inherits_relid_seqno_index"
 #define LanguageNameIndex			"pg_language_name_index"
 #define LanguageOidIndex			"pg_language_oid_index"
+#define LargeobjectLOIdIndex			"pg_largeobject_loid_index"
+#define LargeobjectLOIdPNIndex			"pg_largeobject_loid_pn_index"
 #define ListenerPidRelnameIndex		"pg_listener_pid_relname_index"
 #define OpclassDeftypeIndex			"pg_opclass_deftype_index"
 #define OpclassNameIndex			"pg_opclass_name_index"
@@ -92,6 +95,7 @@ extern char *Name_pg_group_indices[];
 extern char *Name_pg_index_indices[];
 extern char *Name_pg_inherits_indices[];
 extern char *Name_pg_language_indices[];
+extern char *Name_pg_largeobject_indices[];
 extern char *Name_pg_listener_indices[];
 extern char *Name_pg_opclass_indices[];
 extern char *Name_pg_operator_indices[];
@@ -191,6 +195,8 @@ DECLARE_UNIQUE_INDEX(pg_index_indexrelid_index on pg_index using btree(indexreli
 DECLARE_UNIQUE_INDEX(pg_inherits_relid_seqno_index on pg_inherits using btree(inhrelid oid_ops, inhseqno int4_ops));
 DECLARE_UNIQUE_INDEX(pg_language_name_index on pg_language using btree(lanname name_ops));
 DECLARE_UNIQUE_INDEX(pg_language_oid_index on pg_language using btree(oid oid_ops));
+DECLARE_INDEX(pg_largeobject_loid_index on pg_largeobject using btree(loid oid_ops));
+DECLARE_UNIQUE_INDEX(pg_largeobject_loid_pn_index on pg_largeobject using btree(loid oid_ops, pageno int4_ops));
 DECLARE_UNIQUE_INDEX(pg_listener_pid_relname_index on pg_listener using btree(listenerpid int4_ops, relname name_ops));
 /* This column needs to allow multiple zero entries, but is in the cache */
 DECLARE_INDEX(pg_opclass_deftype_index on pg_opclass using btree(opcdeftype oid_ops));

src/include/catalog/pg_largeobject.h

+/*-------------------------------------------------------------------------
+ *
+ * pg_largeobject.h
+ *	  definition of the system "largeobject" relation (pg_largeobject)
+ *	  along with the relation's initial contents.
+ *
+ *
+ * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $Id: pg_largeobject.h,v 1.3 2000/10/21 15:55:28 momjian Exp $
+ *
+ * NOTES
+ *	  the genbki.sh script reads this file and generates .bki
+ *	  information from the DATA() statements.
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_LARGEOBJECT_H
+#define PG_LARGEOBJECT_H
+
+/* ----------------
+ *		postgres.h contains the system type definintions and the
+ *		CATALOG(), BOOTSTRAP and DATA() sugar words so this file
+ *		can be read by both genbki.sh and the C compiler.
+ * ----------------
+ */
+
+/* ----------------
+ *		pg_largeobject definition.  cpp turns this into
+ *		typedef struct FormData_pg_largeobject. Large object id
+ *		is stored in loid;
+ * ----------------
+ */
+
+CATALOG(pg_largeobject)
+{
+	Oid			loid;
+	int4			pageno;
+	bytea			data;
+} FormData_pg_largeobject;
+
+/* ----------------
+ *		Form_pg_largeobject corresponds to a pointer to a tuple with
+ *		the format of pg_largeobject relation.
+ * ----------------
+ */
+typedef FormData_pg_largeobject *Form_pg_largeobject;
+
+/* ----------------
+ *		compiler constants for pg_largeobject
+ * ----------------
+ */
+#define Natts_pg_largeobject			3
+#define Anum_pg_largeobject_loid		1
+#define Anum_pg_largeobject_pageno		2
+#define Anum_pg_largeobject_data		3
+
+Oid LargeobjectCreate(Oid loid);
+void LargeobjectDrop(Oid loid);
+int LargeobjectFind(Oid loid);
+
+#endif	 /* PG_LARGEOBJECT_H */

src/include/storage/large_object.h

@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: large_object.h,v 1.15 2000/10/08 03:53:15 momjian Exp $
+ * $Id: large_object.h,v 1.16 2000/10/21 15:55:29 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -22,17 +22,11 @@
 /*
  * This structure will eventually have lots more stuff associated with it.
  */
-typedef struct LargeObjectDesc
-{
-	Relation	heap_r;			/* heap relation */
-	Relation	index_r;		/* index relation on seqno attribute */
-	IndexScanDesc iscan;		/* index scan we're using */
-	TupleDesc	hdesc;			/* heap relation tuple desc */
-	TupleDesc	idesc;			/* index relation tuple desc */
-	uint32		lowbyte;		/* low byte on the current page */
-	uint32		highbyte;		/* high byte on the current page */
+typedef struct LargeObjectDesc {
+	Relation	heap_r;
+	Relation	index_r;
 	uint32		offset;			/* current seek pointer */
-	ItemPointerData htid;		/* tid of current heap tuple */
+	Oid		id;
 
 #define IFS_RDLOCK		(1 << 0)
 #define IFS_WRLOCK		(1 << 1)
@@ -55,7 +49,4 @@ extern int	inv_tell(LargeObjectDesc *obj_desc);
 extern int	inv_read(LargeObjectDesc *obj_desc, char *buf, int nbytes);
 extern int	inv_write(LargeObjectDesc *obj_desc, char *buf, int nbytes);
 
-/* added for buffer leak prevention [ PA ] */
-extern void inv_cleanindex(LargeObjectDesc *obj_desc);
-
 #endif	 /* LARGE_OBJECT_H */