/*-------------------------------------------------------------------------
 *
 * gist.c
 *	  interface routines for the postgres GiST index access method.
 *
 *
 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.79 2001/06/11 05:00:56 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/genam.h"
#include "access/gist.h"
#include "access/gistscan.h"
#include "access/heapam.h"
#include "catalog/index.h"
#include "catalog/pg_index.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "utils/syscache.h"
#include "access/xlogutils.h"


#undef GIST_PAGEADDITEM

#define ATTSIZE( datum, Rel, i, isnull ) \
	( \
		( isnull ) ? 0 : \
			att_addlength(0, (Rel)->rd_att->attrs[(i)-1]->attlen, (datum)) \
	)

/* result's status */
#define INSERTED	0x01
#define SPLITED		0x02

/* group flags ( in gistSplit ) */
#define LEFT_ADDED	0x01
#define RIGHT_ADDED	0x02
#define BOTH_ADDED	( LEFT_ADDED | RIGHT_ADDED )

/* non-export function prototypes */
static void gistdoinsert(Relation r,
			 IndexTuple itup,
			 InsertIndexResult *res,
			 GISTSTATE *GISTstate);
static int gistlayerinsert(Relation r, BlockNumber blkno,
				IndexTuple **itup,
				int *len,
				InsertIndexResult *res,
				GISTSTATE *giststate);
static OffsetNumber gistwritebuffer(Relation r,
				Page page,
				IndexTuple *itup,
				int len,
				OffsetNumber off,
				GISTSTATE *giststate);
static int gistnospace(Page page,
			IndexTuple *itvec, int len);
static IndexTuple *gistreadbuffer(Relation r,
			   Buffer buffer, int *len);
static IndexTuple *gistjoinvector(
			   IndexTuple *itvec, int *len,
			   IndexTuple *additvec, int addlen);
static IndexTuple gistunion(Relation r, IndexTuple *itvec,
		  int len, GISTSTATE *giststate);

static IndexTuple gistgetadjusted(Relation r,
				IndexTuple oldtup,
				IndexTuple addtup,
				GISTSTATE *giststate);
static int gistfindgroup( GISTSTATE *giststate, 
			GISTENTRY *valvec, GIST_SPLITVEC * spl );
static IndexTuple gistFormTuple( GISTSTATE *giststate, 
			Relation r, Datum attdata[], int datumsize[] );
static IndexTuple *gistSplit(Relation r,
		  Buffer buffer,
		  IndexTuple *itup,
		  int *len,
		  GISTSTATE *giststate,
		  InsertIndexResult *res);
static void gistnewroot(GISTSTATE *giststate, Relation r,
			IndexTuple *itup, int len);
static void GISTInitBuffer(Buffer b, uint32 f);
static OffsetNumber gistchoose(Relation r, Page p,
		   IndexTuple it,
		   GISTSTATE *giststate);
#ifdef GIST_PAGEADDITEM
static IndexTuple gist_tuple_replacekey(Relation r,
					  GISTENTRY entry, IndexTuple t);
#endif
static void gistcentryinit(GISTSTATE *giststate, int nkey,
			   GISTENTRY *e, Datum k,
			   Relation r, Page pg,
			   OffsetNumber o, int b, bool l);
static bool gistDeCompressAtt( 	GISTSTATE *giststate, Relation r, 
				IndexTuple tuple, Page p, OffsetNumber o, 
				GISTENTRY attdata[], bool decompvec[] );
static void gistFreeAtt(  Relation r, GISTENTRY attdata[], bool decompvec[] );
#undef GISTDEBUG

#ifdef GISTDEBUG
static void gist_dumptree(Relation r, int level, BlockNumber blk, OffsetNumber coff);
#endif

/*
 * routine to build an index.  Basically calls insert over and over
 */
Datum
gistbuild(PG_FUNCTION_ARGS)
{
	Relation	heap = (Relation) PG_GETARG_POINTER(0);
	Relation	index = (Relation) PG_GETARG_POINTER(1);
	IndexInfo  *indexInfo = (IndexInfo *) PG_GETARG_POINTER(2);
	Node	   *oldPred = (Node *) PG_GETARG_POINTER(3);

#ifdef NOT_USED
	IndexStrategy istrat = (IndexStrategy) PG_GETARG_POINTER(4);

#endif
	HeapScanDesc hscan;
	HeapTuple	htup;
	IndexTuple	itup;
	TupleDesc	htupdesc,
				itupdesc;
	Datum		attdata[INDEX_MAX_KEYS];
	char		nulls[INDEX_MAX_KEYS];
	double		nhtups,
				nitups;
	Node	   *pred = indexInfo->ii_Predicate;

#ifndef OMIT_PARTIAL_INDEX
	TupleTable	tupleTable;
	TupleTableSlot *slot;

#endif
	ExprContext *econtext;
	GISTSTATE	giststate;
	GISTENTRY	tmpcentry;
	Buffer		buffer = InvalidBuffer;
	bool	   *compvec;
	int			i;

	/* no locking is needed */

	initGISTstate(&giststate, index);

	/*
	 * We expect to be called exactly once for any index relation. If
	 * that's not the case, big trouble's what we have.
	 */
	if (oldPred == NULL && RelationGetNumberOfBlocks(index) != 0)
		elog(ERROR, "%s already contains data", RelationGetRelationName(index));

	/* initialize the root page (if this is a new index) */
	if (oldPred == NULL)
	{
		buffer = ReadBuffer(index, P_NEW);
		GISTInitBuffer(buffer, F_LEAF);
		WriteBuffer(buffer);
	}

	/* get tuple descriptors for heap and index relations */
	htupdesc = RelationGetDescr(heap);
	itupdesc = RelationGetDescr(index);

	/*
	 * If this is a predicate (partial) index, we will need to evaluate
	 * the predicate using ExecQual, which requires the current tuple to
	 * be in a slot of a TupleTable.  In addition, ExecQual must have an
	 * ExprContext referring to that slot.	Here, we initialize dummy
	 * TupleTable and ExprContext objects for this purpose. --Nels, Feb 92
	 *
	 * We construct the ExprContext anyway since we need a per-tuple
	 * temporary memory context for function evaluation -- tgl July 00
	 */
#ifndef OMIT_PARTIAL_INDEX
	if (pred != NULL || oldPred != NULL)
	{
		tupleTable = ExecCreateTupleTable(1);
		slot = ExecAllocTableSlot(tupleTable);
		ExecSetSlotDescriptor(slot, htupdesc, false);
	}
	else
	{
		tupleTable = NULL;
		slot = NULL;
	}
	econtext = MakeExprContext(slot, TransactionCommandContext);
#else
	econtext = MakeExprContext(NULL, TransactionCommandContext);
#endif	 /* OMIT_PARTIAL_INDEX */

	/* build the index */
	nhtups = nitups = 0.0;

	compvec = (bool *) palloc(sizeof(bool) * indexInfo->ii_NumIndexAttrs);

	/* start a heap scan */
	hscan = heap_beginscan(heap, 0, SnapshotNow, 0, (ScanKey) NULL);

	while (HeapTupleIsValid(htup = heap_getnext(hscan, 0)))
	{
		MemoryContextReset(econtext->ecxt_per_tuple_memory);

		nhtups += 1.0;

#ifndef OMIT_PARTIAL_INDEX

		/*
		 * If oldPred != NULL, this is an EXTEND INDEX command, so skip
		 * this tuple if it was already in the existing partial index
		 */
		if (oldPred != NULL)
		{
			slot->val = htup;
			if (ExecQual((List *) oldPred, econtext, false))
			{
				nitups += 1.0;
				continue;
			}
		}

		/*
		 * Skip this tuple if it doesn't satisfy the partial-index
		 * predicate
		 */
		if (pred != NULL)
		{
			slot->val = htup;
			if (!ExecQual((List *) pred, econtext, false))
				continue;
		}
#endif	 /* OMIT_PARTIAL_INDEX */

		nitups += 1.0;

		/*
		 * For the current heap tuple, extract all the attributes we use
		 * in this index, and note which are null.
		 */
		FormIndexDatum(indexInfo,
					   htup,
					   htupdesc,
					   econtext->ecxt_per_tuple_memory,
					   attdata,
					   nulls);

		/* immediately compress keys to normalize */
		for (i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
		{
			gistcentryinit(&giststate, i, &tmpcentry, attdata[i],
						   (Relation) NULL, (Page) NULL, (OffsetNumber) 0,
						   -1 /* size is currently bogus */ , TRUE);
			if (attdata[i] != tmpcentry.key &&
				!(giststate.keytypbyval))
				compvec[i] = TRUE;
			else
				compvec[i] = FALSE;
			attdata[i] = tmpcentry.key;
		}

		/* form an index tuple and point it at the heap tuple */
		itup = index_formtuple(itupdesc, attdata, nulls);
		itup->t_tid = htup->t_self;

		/*
		 * Since we already have the index relation locked, we call
		 * gistdoinsert directly.  Normal access method calls dispatch
		 * through gistinsert, which locks the relation for write.	This
		 * is the right thing to do if you're inserting single tups, but
		 * not when you're initializing the whole index at once.
		 */
		gistdoinsert(index, itup, NULL, &giststate);

		for (i = 0; i < indexInfo->ii_NumIndexAttrs; i++)
			if (compvec[i])
				pfree(DatumGetPointer(attdata[i]));

		pfree(itup);
	}

	/* okay, all heap tuples are indexed */
	heap_endscan(hscan);

	pfree(compvec);

#ifndef OMIT_PARTIAL_INDEX
	if (pred != NULL || oldPred != NULL)
		ExecDropTupleTable(tupleTable, true);
#endif	 /* OMIT_PARTIAL_INDEX */
	FreeExprContext(econtext);

	/*
	 * Since we just counted the tuples in the heap, we update its stats
	 * in pg_class to guarantee that the planner takes advantage of the
	 * index we just created.  But, only update statistics during normal
	 * index definitions, not for indices on system catalogs created
	 * during bootstrap processing.  We must close the relations before
	 * updating statistics to guarantee that the relcache entries are
	 * flushed when we increment the command counter in UpdateStats(). But
	 * we do not release any locks on the relations; those will be held
	 * until end of transaction.
	 */
	if (IsNormalProcessingMode())
	{
		Oid			hrelid = RelationGetRelid(heap);
		Oid			irelid = RelationGetRelid(index);

		heap_close(heap, NoLock);
		index_close(index);
		UpdateStats(hrelid, nhtups);
		UpdateStats(irelid, nitups);
		if (oldPred != NULL)
		{
			if (nitups == nhtups)
				pred = NULL;
			UpdateIndexPredicate(irelid, oldPred, pred);
		}
	}

#ifdef GISTDEBUG
	gist_dumptree(index, 0, GISTP_ROOT, 0);
#endif

	PG_RETURN_VOID();
}

/*
 *	gistinsert -- wrapper for GiST tuple insertion.
 *
 *	  This is the public interface routine for tuple insertion in GiSTs.
 *	  It doesn't do any work; just locks the relation and passes the buck.
 */
Datum
gistinsert(PG_FUNCTION_ARGS)
{
	Relation	r = (Relation) PG_GETARG_POINTER(0);
	Datum	   *datum = (Datum *) PG_GETARG_POINTER(1);
	char	   *nulls = (char *) PG_GETARG_POINTER(2);
	ItemPointer ht_ctid = (ItemPointer) PG_GETARG_POINTER(3);

#ifdef NOT_USED
	Relation	heapRel = (Relation) PG_GETARG_POINTER(4);

#endif
	InsertIndexResult res;
	IndexTuple	itup;
	GISTSTATE	giststate;
	GISTENTRY	tmpentry;
	int			i;
	bool	   *compvec;

	initGISTstate(&giststate, r);

	/* immediately compress keys to normalize */
	compvec = (bool *) palloc(sizeof(bool) * r->rd_att->natts);
	for (i = 0; i < r->rd_att->natts; i++)
	{
		gistcentryinit(&giststate, i,&tmpentry, datum[i],
					   (Relation) NULL, (Page) NULL, (OffsetNumber) 0,
					   -1 /* size is currently bogus */ , TRUE);
		if (datum[i] != tmpentry.key && !(giststate.keytypbyval))
			compvec[i] = TRUE;
		else
			compvec[i] = FALSE;
		datum[i] = tmpentry.key;
	}
	itup = index_formtuple(RelationGetDescr(r), datum, nulls);
	itup->t_tid = *ht_ctid;

	/*
	 * Notes in ExecUtils:ExecOpenIndices()
	 *
	 * RelationSetLockForWrite(r);
	 */

	res = (InsertIndexResult) palloc(sizeof(InsertIndexResultData));
	gistdoinsert(r, itup, &res, &giststate);
	for (i = 0; i < r->rd_att->natts; i++)
		if (compvec[i] == TRUE)
			pfree(DatumGetPointer(datum[i]));
	pfree(itup);
	pfree(compvec);

	PG_RETURN_POINTER(res);
}

#ifdef GIST_PAGEADDITEM
/*
** Take a compressed entry, and install it on a page.  Since we now know
** where the entry will live, we decompress it and recompress it using
** that knowledge (some compression routines may want to fish around
** on the page, for example, or do something special for leaf nodes.)
*/
static OffsetNumber
gistPageAddItem(GISTSTATE *giststate,
				Relation r,
				Page page,
				Item item,
				Size size,
				OffsetNumber offsetNumber,
				ItemIdFlags flags,
				GISTENTRY *dentry,
				IndexTuple *newtup)
{
	GISTENTRY	tmpcentry;
	IndexTuple	itup = (IndexTuple) item;
	OffsetNumber retval;
	Datum		datum;
	bool		IsNull;

	/*
	 * recompress the item given that we now know the exact page and
	 * offset for insertion
	 */
	datum = index_getattr(itup, 1, r->rd_att, &IsNull);
	gistdentryinit(giststate, 0,dentry, datum,
				   (Relation) 0, (Page) 0,
				   (OffsetNumber) InvalidOffsetNumber,
				   ATTSIZE( datum, r, 1, IsNull ),
				   FALSE);
	gistcentryinit(giststate, 0,&tmpcentry, dentry->key, r, page,
				   offsetNumber, dentry->bytes, FALSE);
	*newtup = gist_tuple_replacekey(r, tmpcentry, itup);
	retval = PageAddItem(page, (Item) *newtup, IndexTupleSize(*newtup),
						 offsetNumber, flags);
	if (retval == InvalidOffsetNumber)
		elog(ERROR, "gist: failed to add index item to %s",
			 RelationGetRelationName(r));
	/* be tidy */
	if (DatumGetPointer(tmpcentry.key) != NULL &&
		tmpcentry.key != dentry->key &&
		tmpcentry.key != datum )
		pfree(DatumGetPointer(tmpcentry.key));
	return (retval);
}
#endif

static void
gistdoinsert(Relation r,
			 IndexTuple itup,
			 InsertIndexResult *res,
			 GISTSTATE *giststate)
{
	IndexTuple *instup;
	int			i,
				ret,
				len = 1;

	instup = (IndexTuple *) palloc(sizeof(IndexTuple));
	instup[0] = (IndexTuple) palloc(IndexTupleSize(itup));
	memcpy(instup[0], itup, IndexTupleSize(itup));

	ret = gistlayerinsert(r, GISTP_ROOT, &instup, &len, res, giststate);
	if (ret & SPLITED)
		gistnewroot(giststate, r, instup, len);

	for (i = 0; i < len; i++)
		pfree(instup[i]);
	pfree(instup);
}

static int
gistlayerinsert(Relation r, BlockNumber blkno,
				IndexTuple **itup,		/* in - out, has compressed entry */
				int *len,		/* in - out */
				InsertIndexResult *res, /* out */
				GISTSTATE *giststate)
{
	Buffer		buffer;
	Page		page;
	OffsetNumber child;
	int			ret;
	GISTPageOpaque opaque;

	buffer = ReadBuffer(r, blkno);
	page = (Page) BufferGetPage(buffer);
	opaque = (GISTPageOpaque) PageGetSpecialPointer(page);

	if (!(opaque->flags & F_LEAF))
	{
		/* internal page, so we must walk on tree */
		/* len IS equial 1 */
		ItemId		iid;
		BlockNumber nblkno;
		ItemPointerData oldtid;
		IndexTuple	oldtup;

		child = gistchoose(r, page, *(*itup), giststate);
		iid = PageGetItemId(page, child);
		oldtup = (IndexTuple) PageGetItem(page, iid);
		nblkno = ItemPointerGetBlockNumber(&(oldtup->t_tid));

		/*
		 * After this call: 1. if child page was splited, then itup
		 * contains keys for each page 2. if  child page wasn't splited,
		 * then itup contains additional for adjustement of current key
		 */
		ret = gistlayerinsert(r, nblkno, itup, len, res, giststate);

		/* nothing inserted in child */
		if (!(ret & INSERTED))
		{
			ReleaseBuffer(buffer);
			return 0x00;
		}

		/* child does not splited */
		if (!(ret & SPLITED))
		{
			IndexTuple	newtup = gistgetadjusted(r, oldtup, (*itup)[0], giststate);
			if (!newtup)
			{
				/* not need to update key */
				ReleaseBuffer(buffer);
				return 0x00;
			}

			pfree((*itup)[0]);	/* !!! */
			(*itup)[0] = newtup;
		}

		/* key is modified, so old version must be deleted */
		ItemPointerSet(&oldtid, blkno, child);
		DirectFunctionCall2(gistdelete,
							PointerGetDatum(r),
							PointerGetDatum(&oldtid));
	}

	ret = INSERTED;

	if (gistnospace(page, (*itup), *len))
	{
		/* no space for insertion */
		IndexTuple *itvec, *newitup;
		int tlen,oldlen;

		ret |= SPLITED;
		itvec = gistreadbuffer(r, buffer, &tlen);
		itvec = gistjoinvector(itvec, &tlen, (*itup), *len);
		oldlen = *len;
		newitup = gistSplit(r, buffer, itvec, &tlen, giststate,
							(opaque->flags & F_LEAF) ? res : NULL);		/* res only for
																		 * inserting in leaf */
		ReleaseBuffer(buffer);
		do  
			pfree( (*itup)[ oldlen-1 ] );
		while ( (--oldlen) > 0 );
		pfree((*itup));
		pfree(itvec);
		*itup = newitup;
		*len = tlen;			/* now tlen >= 2 */
	}
	else
	{
		/* enogth space */
		OffsetNumber off,
					l;

		off = (PageIsEmpty(page)) ?
			FirstOffsetNumber
			:
			OffsetNumberNext(PageGetMaxOffsetNumber(page));
		l = gistwritebuffer(r, page, (*itup), *len, off, giststate);
		WriteBuffer(buffer);

		/*
		 * set res if insert into leaf page, in this case, len = 1 always
		 */
		if (res && (opaque->flags & F_LEAF))
			ItemPointerSet(&((*res)->pointerData), blkno, l);

		if (*len > 1)
		{						/* previos insert ret & SPLITED != 0 */
			int			i;

			/*
			 * child was splited, so we must form union for insertion in
			 * parent
			 */
			IndexTuple	newtup = gistunion(r, (*itup), *len, giststate);
			ItemPointerSet(&(newtup->t_tid), blkno, 1); 

			for (i = 0; i < *len; i++)
				pfree((*itup)[i]);
			(*itup)[0] = newtup;
			*len = 1;
		}
	}

	return ret;
}

/*
 * Write itup vector to page, has no control of free space
 */
static OffsetNumber
gistwritebuffer(Relation r, Page page, IndexTuple *itup,
				int len, OffsetNumber off, GISTSTATE *giststate)
{
	OffsetNumber l = InvalidOffsetNumber;
	int			i;
#ifdef GIST_PAGEADDITEM
	GISTENTRY	tmpdentry;
	IndexTuple	newtup;
	bool IsNull;	
#endif
	for (i = 0; i < len; i++)
	{
#ifdef GIST_PAGEADDITEM
		l = gistPageAddItem(giststate, r, page,
							(Item) itup[i], IndexTupleSize(itup[i]),
							off, LP_USED, &tmpdentry, &newtup);
		off = OffsetNumberNext(off);
		if (DatumGetPointer(tmpdentry.key) != NULL &&
			tmpdentry.key != index_getattr(itup[i], 1, r->rd_att, &IsNull))
			pfree(DatumGetPointer(tmpdentry.key));
		if (itup[i] != newtup)
			pfree(newtup);
#else
		l = PageAddItem(page, (Item) itup[i], IndexTupleSize(itup[i]),
			off, LP_USED);
		if (l == InvalidOffsetNumber)
			elog(ERROR, "gist: failed to add index item to %s",
				 RelationGetRelationName(r));
#endif
	}
	return l;
}

/*
 * Check space for itup vector on page
 */
static int
gistnospace(Page page, IndexTuple *itvec, int len)
{
	int			size = 0;
	int			i;

	for (i = 0; i < len; i++)
		size += IndexTupleSize(itvec[i]) + sizeof(ItemIdData);

	return (PageGetFreeSpace(page) < size);
}

/*
 * Read buffer into itup vector
 */
static IndexTuple *
gistreadbuffer(Relation r, Buffer buffer, int *len /* out */ )
{
	OffsetNumber i,
				maxoff;
	IndexTuple *itvec;
	Page		p = (Page) BufferGetPage(buffer);

	maxoff = PageGetMaxOffsetNumber(p);
	*len = maxoff;
	itvec = palloc(sizeof(IndexTuple) * maxoff);
	for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
		itvec[i-1] = (IndexTuple) PageGetItem(p, PageGetItemId(p, i));

	return itvec;
}

/*
 * join two vectors into one
 */
static IndexTuple *
gistjoinvector(IndexTuple *itvec, int *len, IndexTuple *additvec, int addlen)
{
	itvec = (IndexTuple *) repalloc((void *) itvec, sizeof(IndexTuple) * ((*len) + addlen));
	memmove(&itvec[*len], additvec, sizeof(IndexTuple) * addlen);
	*len += addlen;
	return itvec;
}

/*
 * return union of itup vector
 */
static IndexTuple
gistunion(Relation r, IndexTuple *itvec, int len, GISTSTATE *giststate) {
	Datum		attr[INDEX_MAX_KEYS];
	bool	whatfree[INDEX_MAX_KEYS];
	char		isnull[INDEX_MAX_KEYS];
	bytea	   *evec;
	Datum		datum;
	int			datumsize,
				i,j;
	GISTENTRY	centry[INDEX_MAX_KEYS];
	bool	*needfree;
	IndexTuple newtup;
	bool IsNull;

	needfree = (bool *) palloc(len * sizeof(bool));
	evec = (bytea *) palloc(len * sizeof(GISTENTRY) + VARHDRSZ);
	VARATT_SIZEP(evec) = len * sizeof(GISTENTRY) + VARHDRSZ;

	for (j = 0; j < r->rd_att->natts; j++) { 
		for (i = 0; i < len; i++) {
			datum = index_getattr(itvec[i], j+1, r->rd_att, &IsNull);
			gistdentryinit(giststate, j,
						   &((GISTENTRY *) VARDATA(evec))[i],
						   datum,
						   (Relation) NULL, (Page) NULL, (OffsetNumber) NULL,
						   ATTSIZE( datum, r, j+1, IsNull ), FALSE);
			if ( DatumGetPointer(((GISTENTRY *) VARDATA(evec))[i].key) != NULL
				 && ((GISTENTRY *) VARDATA(evec))[i].key != datum ) 
				needfree[i] = TRUE;
			else
				needfree[i] = FALSE; 
		}

		datum = FunctionCall2(&giststate->unionFn[j],
							  PointerGetDatum(evec),
							  PointerGetDatum(&datumsize));

		for (i = 0; i < len; i++)
			if ( needfree[i] )
				pfree(DatumGetPointer(((GISTENTRY *) VARDATA(evec))[i].key));

		gistcentryinit(giststate, j, &centry[j], datum,
			(Relation) NULL, (Page) NULL, (OffsetNumber) NULL,
			datumsize, FALSE);
		isnull[j] = DatumGetPointer(centry[j].key) != NULL ? ' ' : 'n';
		attr[j] =  centry[j].key;
		if ( DatumGetPointer(centry[j].key) != NULL ) {
			whatfree[j] = TRUE;
			if ( centry[j].key != datum )
				pfree(DatumGetPointer(datum));
		} else 
			whatfree[j] = FALSE;
	}

	pfree(evec);
	pfree(needfree);

	newtup = (IndexTuple) index_formtuple(r->rd_att, attr, isnull);
	for (j = 0; j < r->rd_att->natts; j++)
		if ( whatfree[j] )
			pfree(DatumGetPointer(attr[j]));

	return newtup;
}

/*
 * Forms union of oldtup and addtup, if union == oldtup then return NULL
 */
static IndexTuple
gistgetadjusted(Relation r, IndexTuple oldtup, IndexTuple addtup, GISTSTATE *giststate)
{
	bytea	   *evec;
	Datum		datum;
	int			datumsize;
	bool		result, neednew = false;
	char		isnull[INDEX_MAX_KEYS],
				whatfree[INDEX_MAX_KEYS];
	Datum		attr[INDEX_MAX_KEYS];
	GISTENTRY	centry[INDEX_MAX_KEYS],
				oldatt[INDEX_MAX_KEYS],
				addatt[INDEX_MAX_KEYS],
			   *ev0p,
			   *ev1p;
	bool		olddec[INDEX_MAX_KEYS],
				adddec[INDEX_MAX_KEYS];

	IndexTuple	newtup = NULL;
	int j;

	evec = (bytea *) palloc(2 * sizeof(GISTENTRY) + VARHDRSZ);
	VARATT_SIZEP(evec) = 2 * sizeof(GISTENTRY) + VARHDRSZ;
	ev0p = &((GISTENTRY *) VARDATA(evec))[0];
	ev1p = &((GISTENTRY *) VARDATA(evec))[1];
	
	gistDeCompressAtt( giststate, r, oldtup, (Page) NULL, 
		(OffsetNumber) 0, oldatt, olddec);

	gistDeCompressAtt( giststate, r, addtup, (Page) NULL, 
		(OffsetNumber) 0, addatt, adddec);

		
	for( j=0; j<r->rd_att->natts; j++ ) {
		gistentryinit(*ev0p, oldatt[j].key, r, (Page) NULL, 
			(OffsetNumber) 0, oldatt[j].bytes, FALSE);
		gistentryinit(*ev1p, addatt[j].key, r, (Page) NULL, 
			(OffsetNumber) 0, addatt[j].bytes, FALSE);

		datum = FunctionCall2(&giststate->unionFn[j],
							  PointerGetDatum(evec),
							  PointerGetDatum(&datumsize));

		if (!(DatumGetPointer(ev0p->key) != NULL &&
			  DatumGetPointer(ev1p->key) != NULL))
			result = (DatumGetPointer(ev0p->key) == NULL &&
					  DatumGetPointer(ev1p->key) == NULL);
		else
		{
			FunctionCall3(&giststate->equalFn[j],
						  ev0p->key,
						  datum,
						  PointerGetDatum(&result));
		}
		if ( !result ) 
			neednew = true;

		if ( olddec[j] && DatumGetPointer(oldatt[j].key) != NULL )
			pfree( DatumGetPointer(oldatt[j].key) );
		if ( adddec[j] && DatumGetPointer(addatt[j].key) != NULL )
			pfree( DatumGetPointer(addatt[j].key) );

		gistcentryinit(giststate, j, &centry[j], datum,
			(Relation) NULL, (Page) NULL, (OffsetNumber) NULL,
			datumsize, FALSE);
	
		isnull[j] = DatumGetPointer(centry[j].key) != NULL ? ' ' : 'n';
		attr[j] =  centry[j].key;
		if ( DatumGetPointer(centry[j].key) != NULL ) {
			whatfree[j] = TRUE;
			if ( centry[j].key != datum )
				pfree(DatumGetPointer(datum));
		} else
			whatfree[j] = FALSE;

	} 
	pfree(evec);

	if (neednew) {
		/* need to update key */
		newtup = (IndexTuple) index_formtuple(r->rd_att, attr, isnull);
		newtup->t_tid = oldtup->t_tid;
	}
	
	for (j = 0; j < r->rd_att->natts; j++)
		if ( whatfree[j] )
			pfree(DatumGetPointer(attr[j]));

	return newtup;
}

static void
gistunionsubkey( Relation r, GISTSTATE *giststate, IndexTuple *itvec, GIST_SPLITVEC * spl ) {
	int i,j,lr;
	Datum	   *attr;
	bool *needfree, IsNull;
	int len, *attrsize;
	OffsetNumber	*entries;
	bytea      *evec;
	Datum		datum;
	int datumsize;

	for(lr=0;lr<=1;lr++) {	
		if ( lr ) {
			attrsize = spl->spl_lattrsize;
			attr = spl->spl_lattr;
			len = spl->spl_nleft;
			entries = spl->spl_left;
		} else {
			attrsize = spl->spl_rattrsize;
			attr = spl->spl_rattr;
			len = spl->spl_nright;
			entries = spl->spl_right;
		}

	 	needfree =  (bool *) palloc( (( len==1 ) ? 2 : len ) * sizeof(bool));
		evec     = (bytea *) palloc( (( len==1 ) ? 2 : len ) * sizeof(GISTENTRY) + VARHDRSZ);
		VARATT_SIZEP(evec) =         (( len==1 ) ? 2 : len ) * sizeof(GISTENTRY) + VARHDRSZ;
		for (j = 1; j < r->rd_att->natts; j++) {
			for (i = 0; i < len; i++) {
				if ( spl->spl_idgrp[ entries[i] ] )
				{
					datum = (Datum) 0;
					IsNull = true;
				} else
					datum = index_getattr(itvec[ entries[i]-1 ], j+1,
										  r->rd_att, &IsNull);
				gistdentryinit(giststate, j,
							   &((GISTENTRY *) VARDATA(evec))[i],
							   datum,
							   (Relation) NULL, (Page) NULL,
							   (OffsetNumber) NULL,
							   ATTSIZE( datum, r, j+1, IsNull ), FALSE);
				if ( DatumGetPointer(((GISTENTRY *) VARDATA(evec))[i].key) != NULL &&
						((GISTENTRY *) VARDATA(evec))[i].key != datum )
					needfree[i] = TRUE;
				else
					needfree[i] = FALSE;
			
			} 
			if ( len == 1 &&
				 DatumGetPointer(((GISTENTRY *) VARDATA(evec))[0].key) == NULL)
			{
				datum = (Datum) 0;
				datumsize = 0;
			} else {
				/*
				 * ((GISTENTRY *) VARDATA(evec))[0].bytes may be not defined,
				 * so form union with itself
				 */
				if ( len == 1 ) {
					memcpy(	(void*) &((GISTENTRY *) VARDATA(evec))[1],
						(void*) &((GISTENTRY *) VARDATA(evec))[0],
						sizeof( GISTENTRY ) );
				}
				datum = FunctionCall2(&giststate->unionFn[j],
									  PointerGetDatum(evec),
									  PointerGetDatum(&datumsize));
			} 

			for (i = 0; i < len; i++)
				if ( needfree[i] )
					pfree(DatumGetPointer(((GISTENTRY *) VARDATA(evec))[i].key));
			
			attr[j] = datum;
			attrsize[j] = datumsize;
		}
		pfree(evec);
		pfree(needfree);
	}
}

/*
 * find group in vector with equial value 
 */
static int
gistfindgroup( GISTSTATE *giststate, GISTENTRY *valvec, GIST_SPLITVEC * spl ) {
	int i,j,len;
	int curid = 1;
	bool result;

	for(i=0; i<spl->spl_nleft; i++) {
		if ( spl->spl_idgrp[ spl->spl_left[i] ]) continue;
		len = 0;
		/* find all equal value in right part */
		for(j=0; j < spl->spl_nright; j++) {
			if ( spl->spl_idgrp[ spl->spl_right[j] ]) continue;
			if (!(DatumGetPointer(valvec[ spl->spl_left[i] ].key) != NULL &&
				  DatumGetPointer(valvec[ spl->spl_right[j]].key) != NULL))
				result =
					DatumGetPointer(valvec[ spl->spl_left[i] ].key) == NULL && 
					DatumGetPointer(valvec[ spl->spl_right[j]].key) == NULL;
			else
				FunctionCall3(&giststate->equalFn[0],
							  valvec[ spl->spl_left[i]  ].key,
							  valvec[ spl->spl_right[j] ].key,
							  PointerGetDatum(&result));
			if ( result ) {
				spl->spl_idgrp[ spl->spl_right[j] ] = curid;
				len++;
			}
		}
		/* find all other equal value in left part */
		if ( len ) {
			/* add current val to list of equial values*/
			spl->spl_idgrp[ spl->spl_left[i] ]=curid;
			/* searching .. */
			for(j=i+1; j < spl->spl_nleft; j++) {
				if ( spl->spl_idgrp[ spl->spl_left[j] ]) continue;
				if (!(DatumGetPointer(valvec[ spl->spl_left[i]].key) != NULL &&
					  DatumGetPointer(valvec[ spl->spl_left[j]].key) != NULL))
					result =
						DatumGetPointer(valvec[ spl->spl_left[i]].key) == NULL && 
						DatumGetPointer(valvec[ spl->spl_left[j]].key) == NULL;
				else
					FunctionCall3(&giststate->equalFn[0],
								  valvec[ spl->spl_left[i]  ].key,
								  valvec[ spl->spl_left[j]  ].key,
								  PointerGetDatum(&result));
				if ( result ) {
					spl->spl_idgrp[ spl->spl_left[j] ] = curid;
					len++;
				}
			}
			spl->spl_ngrp[curid] = len+1;
			curid++;
		}
	}

	return curid;
}

/*
 *	gistSplit -- split a page in the tree.
 */
static IndexTuple *
gistSplit(Relation r,
		  Buffer buffer,
		  IndexTuple *itup,		/* contains compressed entry */
		  int *len,
		  GISTSTATE *giststate,
		  InsertIndexResult *res)
{
	Page		p;
	Buffer		leftbuf,
				rightbuf;
	Page		left,
				right;
	IndexTuple *lvectup,
			   *rvectup,
			   *newtup;
	BlockNumber lbknum,
				rbknum;
	GISTPageOpaque opaque;
	GIST_SPLITVEC v;
	bytea	   *entryvec;
	bool	   *decompvec;
	int			i,j,
				nlen;
	int MaxGrpId	= 1;
	Datum		datum;
	bool IsNull;

	p = (Page) BufferGetPage(buffer);
	opaque = (GISTPageOpaque) PageGetSpecialPointer(p);


	/*
	 * The root of the tree is the first block in the relation.  If we're
	 * about to split the root, we need to do some hocus-pocus to enforce
	 * this guarantee.
	 */

	if (BufferGetBlockNumber(buffer) == GISTP_ROOT)
	{
		leftbuf = ReadBuffer(r, P_NEW);
		GISTInitBuffer(leftbuf, opaque->flags);
		lbknum = BufferGetBlockNumber(leftbuf);
		left = (Page) BufferGetPage(leftbuf);
	}
	else
	{
		leftbuf = buffer;
		IncrBufferRefCount(buffer);
		lbknum = BufferGetBlockNumber(buffer);
		left = (Page) PageGetTempPage(p, sizeof(GISTPageOpaqueData));
	}

	rightbuf = ReadBuffer(r, P_NEW);
	GISTInitBuffer(rightbuf, opaque->flags);
	rbknum = BufferGetBlockNumber(rightbuf);
	right = (Page) BufferGetPage(rightbuf);

	/* generate the item array */
	entryvec = (bytea *) palloc(VARHDRSZ + (*len + 1) * sizeof(GISTENTRY));
	decompvec = (bool *) palloc(VARHDRSZ + (*len + 1) * sizeof(bool));
	VARATT_SIZEP(entryvec) = (*len + 1) * sizeof(GISTENTRY) + VARHDRSZ;
	for (i = 1; i <= *len; i++)
	{
		datum = index_getattr(itup[i - 1], 1, r->rd_att, &IsNull);
		gistdentryinit(giststate, 0,&((GISTENTRY *) VARDATA(entryvec))[i],
					datum, r, p, i,
					ATTSIZE( datum, r, 1, IsNull ), FALSE);
		if (((GISTENTRY *) VARDATA(entryvec))[i].key == datum ||
			DatumGetPointer(((GISTENTRY *) VARDATA(entryvec))[i].key) == NULL)
			decompvec[i] = FALSE;
		else
			decompvec[i] = TRUE;
	}

	/* now let the user-defined picksplit function set up the split vector */
	FunctionCall2(&giststate->picksplitFn[0],
				  PointerGetDatum(entryvec),
				  PointerGetDatum(&v));

	/* compatibility with old code */	
	if ( v.spl_left[ v.spl_nleft-1 ] == InvalidOffsetNumber ) 
		v.spl_left[ v.spl_nleft-1 ] = (OffsetNumber)*len;
	if ( v.spl_right[ v.spl_nright-1 ] == InvalidOffsetNumber ) 
		v.spl_right[ v.spl_nright-1 ] = (OffsetNumber)*len;
	
	v.spl_lattr[0] = v.spl_ldatum; 
	v.spl_rattr[0] = v.spl_rdatum;

	/* if index is multikey, then we must to try get smaller
	 * bounding box for subkey(s)
         */
	if ( r->rd_att->natts > 1 ) {
		v.spl_idgrp  = (int*) palloc( sizeof(int) * (*len + 1) );
		MemSet((void*)v.spl_idgrp, 0, sizeof(int) * (*len + 1) );
		v.spl_grpflag = (char*) palloc( sizeof(char) * (*len + 1) );
		MemSet((void*)v.spl_grpflag, 0, sizeof(char) * (*len + 1) );
		v.spl_ngrp    = (int*) palloc( sizeof(int) * (*len + 1) );

		MaxGrpId = gistfindgroup( giststate, (GISTENTRY *) VARDATA(entryvec), &v );

		/* form union of sub keys for each page (l,p) */
		gistunionsubkey( r, giststate, itup, &v );

		/* if possible, we insert equivalrnt tuples
		 * with control by penalty for a subkey(s)
                 */
		if ( MaxGrpId > 1 ) {
			int	curlen;
			OffsetNumber 	*curwpos;
			bool decfree[INDEX_MAX_KEYS];
			GISTENTRY entry,identry[INDEX_MAX_KEYS], *ev0p, *ev1p;
			float lpenalty, rpenalty;
			bytea      *evec;
			int 	datumsize;

			/* clear vectors */
			curlen = v.spl_nleft;
			curwpos = v.spl_left;
			for( i=0; i<v.spl_nleft;i++ )
				if ( v.spl_idgrp[ v.spl_left[i] ] == 0 ) {
					*curwpos = v.spl_left[i];
					curwpos++;
				} else
					curlen--;
			v.spl_nleft = curlen;

			curlen = v.spl_nright;
			curwpos = v.spl_right;
			for( i=0; i<v.spl_nright;i++ )
				if ( v.spl_idgrp[ v.spl_right[i] ] == 0 ) {
					*curwpos = v.spl_right[i];
					curwpos++;
				} else
					curlen--;
			v.spl_nright = curlen;

			evec = (bytea *) palloc(2 * sizeof(GISTENTRY) + VARHDRSZ);
			VARATT_SIZEP(evec) = 2 * sizeof(GISTENTRY) + VARHDRSZ;
			ev0p = &((GISTENTRY *) VARDATA(evec))[0];
			ev1p = &((GISTENTRY *) VARDATA(evec))[1];

			/* add equivalent tuple */
			for(i = 0; i< *len; i++) {
				if ( v.spl_idgrp[ i+1 ]==0 ) /* already inserted */
					continue;
				gistDeCompressAtt( giststate, r, itup[i], (Page) NULL, (OffsetNumber) 0,
					identry, decfree);

				v.spl_ngrp[ v.spl_idgrp[ i+1 ] ]--;
				if ( v.spl_ngrp[ v.spl_idgrp[ i+1 ] ] == 0 && 
					(v.spl_grpflag[ v.spl_idgrp[ i+1 ] ] & BOTH_ADDED) != BOTH_ADDED ) {

					/* force last in group */
					rpenalty = 1.0;
					lpenalty = ( v.spl_grpflag[ v.spl_idgrp[ i+1 ] ] & LEFT_ADDED ) ? 2.0 : 0.0;
				} else { 
					/*where?*/
					for( j=1; j<r->rd_att->natts; j++ ) {
						gistentryinit(entry,v.spl_lattr[j], r, (Page) NULL,
							(OffsetNumber) 0, v.spl_lattrsize[j], FALSE);
						FunctionCall3(&giststate->penaltyFn[j],
							PointerGetDatum(&entry),
							PointerGetDatum(&identry[j]),
							PointerGetDatum(&lpenalty));
	
						gistentryinit(entry,v.spl_rattr[j], r, (Page) NULL,
							(OffsetNumber) 0, v.spl_rattrsize[j], FALSE);
						FunctionCall3(&giststate->penaltyFn[j],
							PointerGetDatum(&entry),
							PointerGetDatum(&identry[j]),
							PointerGetDatum(&rpenalty));
	
						if ( lpenalty != rpenalty ) 
							break;
					}
				}
				/* add */
				if ( lpenalty < rpenalty ) {
					v.spl_grpflag[ v.spl_idgrp[ i+1 ] ] |= LEFT_ADDED;
					v.spl_left[ v.spl_nleft ] = i+1;
					v.spl_nleft++;
					for( j=1; j<r->rd_att->natts; j++ ) {
						gistentryinit(*ev0p, v.spl_lattr[j], r, (Page) NULL, 
							(OffsetNumber) 0, v.spl_lattrsize[j], FALSE);
						gistentryinit(*ev1p, identry[j].key, r, (Page) NULL, 
							(OffsetNumber) 0, identry[j].bytes, FALSE);

						datum = FunctionCall2(&giststate->unionFn[j],
											  PointerGetDatum(evec),
											  PointerGetDatum(&datumsize));

						if ( DatumGetPointer(v.spl_lattr[j]) != NULL )
							pfree( DatumGetPointer(v.spl_lattr[j]) );

						v.spl_lattr[j] = datum;
						v.spl_lattrsize[j] = datumsize;
					}
				} else {
					v.spl_grpflag[ v.spl_idgrp[ i+1 ] ] |= RIGHT_ADDED;
					v.spl_right[ v.spl_nright ] = i+1;
					v.spl_nright++;
					for( j=1; j<r->rd_att->natts; j++ ) {
						gistentryinit(*ev0p, v.spl_rattr[j], r, (Page) NULL, 
							(OffsetNumber) 0, v.spl_rattrsize[j], FALSE);
						gistentryinit(*ev1p, identry[j].key, r, (Page) NULL, 
							(OffsetNumber) 0, identry[j].bytes, FALSE);

						datum = FunctionCall2(&giststate->unionFn[j],
											  PointerGetDatum(evec),
											  PointerGetDatum(&datumsize));

						if ( DatumGetPointer(v.spl_rattr[j]) != NULL )
							pfree( DatumGetPointer(v.spl_rattr[j]) );

						v.spl_rattr[j] = datum;
						v.spl_rattrsize[j] = datumsize;
					}

				} 
				gistFreeAtt( r, identry, decfree );
			}
			pfree(evec);
		}		
		pfree( v.spl_idgrp );
		pfree( v.spl_grpflag );
		pfree( v.spl_ngrp );
	} 

	/* clean up the entry vector: its keys need to be deleted, too */
	for (i = 1; i <= *len; i++)
		if (decompvec[i])
			pfree(DatumGetPointer(((GISTENTRY *) VARDATA(entryvec))[i].key));
	pfree(entryvec);
	pfree(decompvec);

	/* form left and right vector */
	lvectup = (IndexTuple *) palloc(sizeof(IndexTuple) * v.spl_nleft);
	rvectup = (IndexTuple *) palloc(sizeof(IndexTuple) * v.spl_nright);

	for(i=0; i<v.spl_nleft;i++) 
		lvectup[i] = itup[ v.spl_left[i] - 1 ];

	for(i=0; i<v.spl_nright;i++) 
		rvectup[i] = itup[ v.spl_right[i] - 1 ];

	/* write on disk (may be need another split) */
	if (gistnospace(right, rvectup, v.spl_nright))
	{
		nlen = v.spl_nright;
		newtup = gistSplit(r, rightbuf, rvectup, &nlen, giststate,
			  (res && rvectup[nlen - 1] == itup[*len - 1]) ? res : NULL);
		ReleaseBuffer(rightbuf);
		for( j=1; j<r->rd_att->natts; j++ ) 
			if ( DatumGetPointer(v.spl_rattr[j]) != NULL )
				pfree( DatumGetPointer(v.spl_rattr[j]) ); 
	}
	else
	{
		OffsetNumber l;

		l = gistwritebuffer(r, right, rvectup, v.spl_nright, FirstOffsetNumber, giststate);
		WriteBuffer(rightbuf);

		if (res)
			ItemPointerSet(&((*res)->pointerData), rbknum, l);

		nlen = 1;
		newtup = (IndexTuple *) palloc(sizeof(IndexTuple) * 1);
		newtup[0] = gistFormTuple( giststate, r, v.spl_rattr, v.spl_rattrsize ); 
		ItemPointerSet(&(newtup[0]->t_tid), rbknum, 1);
	}


	if (gistnospace(left, lvectup, v.spl_nleft))
	{
		int			llen = v.spl_nleft;
		IndexTuple *lntup;

		lntup = gistSplit(r, leftbuf, lvectup, &llen, giststate,
			  (res && lvectup[llen - 1] == itup[*len - 1]) ? res : NULL);
		ReleaseBuffer(leftbuf);

		for( j=1; j<r->rd_att->natts; j++ ) 
			if ( DatumGetPointer(v.spl_lattr[j]) != NULL )
				pfree( DatumGetPointer(v.spl_lattr[j]) ); 

		newtup = gistjoinvector(newtup, &nlen, lntup, llen);
		pfree(lntup);
	}
	else
	{
		OffsetNumber l;

		l = gistwritebuffer(r, left, lvectup, v.spl_nleft, FirstOffsetNumber, giststate);
		if (BufferGetBlockNumber(buffer) != GISTP_ROOT)
			PageRestoreTempPage(left, p);

		WriteBuffer(leftbuf);

		if (res)
			ItemPointerSet(&((*res)->pointerData), lbknum, l);

		nlen += 1;
		newtup = (IndexTuple *) repalloc((void *) newtup, sizeof(IndexTuple) * nlen);
		newtup[nlen - 1] = gistFormTuple( giststate, r, v.spl_lattr, v.spl_lattrsize );
		ItemPointerSet(&(newtup[nlen - 1]->t_tid), lbknum, 1);
	}


	/* adjust active scans */
	gistadjscans(r, GISTOP_SPLIT, BufferGetBlockNumber(buffer), FirstOffsetNumber);

	/* !!! pfree */
	pfree(rvectup);
	pfree(lvectup);
	pfree(v.spl_left);
	pfree(v.spl_right);

	*len = nlen;
	return newtup;
}

static void
gistnewroot(GISTSTATE *giststate, Relation r, IndexTuple *itup, int len)
{
	Buffer		b;
	Page		p;

	b = ReadBuffer(r, GISTP_ROOT);
	GISTInitBuffer(b, 0);
	p = BufferGetPage(b);

	gistwritebuffer(r, p, itup, len, FirstOffsetNumber, giststate);
	WriteBuffer(b);
}

static void
GISTInitBuffer(Buffer b, uint32 f)
{
	GISTPageOpaque opaque;
	Page		page;
	Size		pageSize;

	pageSize = BufferGetPageSize(b);

	page = BufferGetPage(b);
	MemSet(page, 0, (int) pageSize);
	PageInit(page, pageSize, sizeof(GISTPageOpaqueData));

	opaque = (GISTPageOpaque) PageGetSpecialPointer(page);
	opaque->flags = f;
}


/*
** find entry with lowest penalty
*/
static OffsetNumber
gistchoose(Relation r, Page p, IndexTuple it,	/* it has compressed entry */
		   GISTSTATE *giststate)
{
	OffsetNumber maxoff;
	OffsetNumber i;
	Datum		datum;
	float		usize;
	OffsetNumber which;
	float		sum_grow, which_grow[INDEX_MAX_KEYS];
	GISTENTRY	entry,
				identry[INDEX_MAX_KEYS];
	bool IsNull, decompvec[INDEX_MAX_KEYS];
	int j;

	maxoff = PageGetMaxOffsetNumber(p);
	*which_grow = -1.0;
	which = -1;
	sum_grow=1;
	gistDeCompressAtt( giststate, r, 
                                it, (Page) NULL, (OffsetNumber) 0, 
                                identry, decompvec );

	for (i = FirstOffsetNumber; i <= maxoff && sum_grow; i = OffsetNumberNext(i))
	{
		sum_grow=0;
		for (j=0; j<r->rd_att->natts; j++) {
			IndexTuple itup = (IndexTuple) PageGetItem(p, PageGetItemId(p, i));

			datum = index_getattr(itup, j+1, r->rd_att, &IsNull);
			gistdentryinit(giststate, j, &entry, datum, r, p, i, ATTSIZE( datum, r, j+1, IsNull ), FALSE);
			FunctionCall3(&giststate->penaltyFn[j],
						  PointerGetDatum(&entry),
						  PointerGetDatum(&identry[j]),
						  PointerGetDatum(&usize));

			if (DatumGetPointer(entry.key) != NULL && entry.key != datum) 
				pfree(DatumGetPointer(entry.key));

			if ( which_grow[j]<0 || usize < which_grow[j] ) {
				which = i;
				which_grow[j] = usize;
				if ( j<r->rd_att->natts-1 && i==FirstOffsetNumber ) which_grow[j+1]=-1;
				sum_grow += which_grow[j]; 
			} else if ( which_grow[j] == usize )  {
				sum_grow += usize;
			} else {
				sum_grow=1;
				break;
			}
		}
	}

	gistFreeAtt( r, identry, decompvec );
	return which;
}

void
gistfreestack(GISTSTACK *s)
{
	GISTSTACK  *p;

	while (s != (GISTSTACK *) NULL)
	{
		p = s->gs_parent;
		pfree(s);
		s = p;
	}
}


/*
** remove an entry from a page
*/
Datum
gistdelete(PG_FUNCTION_ARGS)
{
	Relation	r = (Relation) PG_GETARG_POINTER(0);
	ItemPointer tid = (ItemPointer) PG_GETARG_POINTER(1);
	BlockNumber blkno;
	OffsetNumber offnum;
	Buffer		buf;
	Page		page;

	/*
	 * Notes in ExecUtils:ExecOpenIndices() Also note that only vacuum
	 * deletes index tuples now...
	 *
	 * RelationSetLockForWrite(r);
	 */

	blkno = ItemPointerGetBlockNumber(tid);
	offnum = ItemPointerGetOffsetNumber(tid);

	/* adjust any scans that will be affected by this deletion */
	gistadjscans(r, GISTOP_DEL, blkno, offnum);

	/* delete the index tuple */
	buf = ReadBuffer(r, blkno);
	page = BufferGetPage(buf);

	PageIndexTupleDelete(page, offnum);

	WriteBuffer(buf);

	PG_RETURN_VOID();
}

void
initGISTstate(GISTSTATE *giststate, Relation index)
{
	RegProcedure consistent_proc,
				union_proc,
				compress_proc,
				decompress_proc;
	RegProcedure penalty_proc,
				picksplit_proc,
				equal_proc;
	HeapTuple	htup;
	Form_pg_index itupform;
	Oid			indexrelid;
	int i;

        if (index->rd_att->natts >= INDEX_MAX_KEYS)
                elog(ERROR, "initGISTstate: numberOfAttributes %d > %d",
                         index->rd_att->natts, INDEX_MAX_KEYS);

	for(i=0; i<index->rd_att->natts; i++) {
		consistent_proc = index_getprocid(index, i+1, GIST_CONSISTENT_PROC	);
		union_proc 	= index_getprocid(index, i+1, GIST_UNION_PROC		);
		compress_proc 	= index_getprocid(index, i+1, GIST_COMPRESS_PROC	);
		decompress_proc = index_getprocid(index, i+1, GIST_DECOMPRESS_PROC	);
		penalty_proc 	= index_getprocid(index, i+1, GIST_PENALTY_PROC		);
		picksplit_proc 	= index_getprocid(index, i+1, GIST_PICKSPLIT_PROC	);
		equal_proc 	= index_getprocid(index, i+1, GIST_EQUAL_PROC		);
		fmgr_info(consistent_proc, 	&((giststate->consistentFn)[i]) 	);
		fmgr_info(union_proc, 		&((giststate->unionFn)[i]) 		);
		fmgr_info(compress_proc, 	&((giststate->compressFn)[i]) 		);
		fmgr_info(decompress_proc, 	&((giststate->decompressFn)[i]) 	);
		fmgr_info(penalty_proc, 	&((giststate->penaltyFn)[i]) 		);
		fmgr_info(picksplit_proc, 	&((giststate->picksplitFn)[i]) 		);
		fmgr_info(equal_proc, 		&((giststate->equalFn)[i]) 		);
	}

	/* see if key type is different from type of attribute being indexed */
	htup = SearchSysCache(INDEXRELID,
						  ObjectIdGetDatum(RelationGetRelid(index)),
						  0, 0, 0);
	if (!HeapTupleIsValid(htup))
		elog(ERROR, "initGISTstate: index %u not found",
			 RelationGetRelid(index));
	itupform = (Form_pg_index) GETSTRUCT(htup);
	giststate->haskeytype = itupform->indhaskeytype;
	indexrelid = itupform->indexrelid;
	ReleaseSysCache(htup);

	if (giststate->haskeytype)
	{
		/* key type is different -- is it byval? */
		htup = SearchSysCache(ATTNUM,
							  ObjectIdGetDatum(indexrelid),
							  UInt16GetDatum(FirstOffsetNumber),
							  0, 0);
		if (!HeapTupleIsValid(htup))
			elog(ERROR, "initGISTstate: no attribute tuple %u %d",
				 indexrelid, FirstOffsetNumber);
		giststate->keytypbyval = (((Form_pg_attribute) htup)->attbyval);
		ReleaseSysCache(htup);
	}
	else
		giststate->keytypbyval = FALSE;
}

#ifdef GIST_PAGEADDITEM
/*
** Given an IndexTuple to be inserted on a page, this routine replaces
** the key with another key, which may involve generating a new IndexTuple
** if the sizes don't match or if the null status changes.
**
** XXX this only works for a single-column index tuple!
*/
static IndexTuple
gist_tuple_replacekey(Relation r, GISTENTRY entry, IndexTuple t)
{
	bool IsNull;
	Datum	datum = index_getattr(t, 1, r->rd_att, &IsNull);

	/*
	 * If new entry fits in index tuple, copy it in.  To avoid worrying
	 * about null-value bitmask, pass it off to the general index_formtuple
	 * routine if either the previous or new value is NULL.
	 */
	if (!IsNull && DatumGetPointer(entry.key) != NULL &&
		(Size) entry.bytes <= ATTSIZE(datum, r, 1, IsNull))
	{
		memcpy(DatumGetPointer(datum),
			   DatumGetPointer(entry.key),
			   entry.bytes);
		/* clear out old size */
		t->t_info &= ~INDEX_SIZE_MASK;
		/* or in new size */
		t->t_info |= MAXALIGN(entry.bytes + sizeof(IndexTupleData));

		return t;
	}
	else
	{
		/* generate a new index tuple for the compressed entry */
		TupleDesc	tupDesc = r->rd_att;
		IndexTuple	newtup;
		char		isnull;

		isnull = DatumGetPointer(entry.key) != NULL ? ' ' : 'n';
		newtup = (IndexTuple) index_formtuple(tupDesc,
											  &(entry.key),
											  &isnull);
		newtup->t_tid = t->t_tid;
		return newtup;
	}
}
#endif

/*
** initialize a GiST entry with a decompressed version of key
*/
void
gistdentryinit(GISTSTATE *giststate, int nkey, GISTENTRY *e,
			   Datum k, Relation r, Page pg, OffsetNumber o,
			   int b, bool l)
{
	GISTENTRY  *dep;

	gistentryinit(*e, k, r, pg, o, b, l);
	if (giststate->haskeytype)
	{
		if ( b ) {
			dep = (GISTENTRY *)
				DatumGetPointer(FunctionCall1(&giststate->decompressFn[nkey],
										  PointerGetDatum(e)));
			gistentryinit(*e, dep->key, dep->rel, dep->page, dep->offset, dep->bytes,
					  dep->leafkey);
			if (dep != e)
				pfree(dep);
		} else {
			gistentryinit(*e, (Datum) 0, r, pg, o, 0, l);
		}
	}
}


/*
** initialize a GiST entry with a compressed version of key
*/
static void
gistcentryinit(GISTSTATE *giststate, int nkey,
			   GISTENTRY *e, Datum k, Relation r,
			   Page pg, OffsetNumber o, int b, bool l)
{
	GISTENTRY  *cep;

	gistentryinit(*e, k, r, pg, o, b, l);
	if (giststate->haskeytype)
	{
		cep = (GISTENTRY *)
			DatumGetPointer(FunctionCall1(&giststate->compressFn[nkey],
										  PointerGetDatum(e)));
		gistentryinit(*e, cep->key, cep->rel, cep->page, cep->offset,
					  cep->bytes, cep->leafkey);
		if (cep != e)
			pfree(cep);
	}
}

static IndexTuple
gistFormTuple( GISTSTATE *giststate, Relation r,
			   Datum attdata[], int datumsize[] )
{
	IndexTuple	tup;
	char            isnull[INDEX_MAX_KEYS];
	bool    whatfree[INDEX_MAX_KEYS];
	GISTENTRY       centry[INDEX_MAX_KEYS];
	Datum	compatt[INDEX_MAX_KEYS];
	int j;
	
	for (j = 0; j < r->rd_att->natts; j++) {
		gistcentryinit(giststate, j, &centry[j], attdata[j],
			(Relation) NULL, (Page) NULL, (OffsetNumber) NULL,
			datumsize[j], FALSE);
		isnull[j] = DatumGetPointer(centry[j].key) != NULL ? ' ' : 'n';
		compatt[j] = centry[j].key;
		if ( DatumGetPointer(centry[j].key) != NULL ) {
			whatfree[j] = TRUE;
			if ( centry[j].key != attdata[j] )
				pfree(DatumGetPointer(attdata[j]));
		} else
			whatfree[j] = FALSE;
	}

	tup = (IndexTuple) index_formtuple(r->rd_att, compatt, isnull);
	for (j = 0; j < r->rd_att->natts; j++)
		if ( whatfree[j] ) pfree(DatumGetPointer(compatt[j]));

	return  tup;
}  

static bool
gistDeCompressAtt( GISTSTATE *giststate, Relation r, IndexTuple tuple, Page p, 
			OffsetNumber o, GISTENTRY attdata[], bool decompvec[] ) {
	bool allIsNull=true;
	bool IsNull;
	int i;
	Datum	datum;

	for(i=0; i < r->rd_att->natts; i++ ) {
		datum = index_getattr(tuple, i+1, r->rd_att, &IsNull);
		if ( ! IsNull ) allIsNull = false;
		gistdentryinit(giststate, i, &attdata[i],
					datum, r, p, o,
					ATTSIZE( datum, r, i+1, IsNull ), FALSE);
		if (attdata[i].key == datum ||
			DatumGetPointer(attdata[i].key) == NULL )
			decompvec[i] = FALSE;
		else
			decompvec[i] = TRUE;
	}

	return allIsNull;
} 

static void
gistFreeAtt(  Relation r, GISTENTRY attdata[], bool decompvec[] ) {
	int i;
	for(i=0; i < r->rd_att->natts; i++ )
		if ( decompvec[i] && DatumGetPointer(attdata[i].key) != NULL )
			pfree( DatumGetPointer(attdata[i].key) );
}
 
#ifdef GISTDEBUG
static void
gist_dumptree(Relation r, int level, BlockNumber blk, OffsetNumber coff)
{
	Buffer		buffer;
	Page		page;
	GISTPageOpaque opaque;
	IndexTuple	which;
	ItemId		iid;
	OffsetNumber i,
				maxoff;
	BlockNumber cblk;
	char	   *pred;

	pred = (char *) palloc(sizeof(char) * level + 1);
	MemSet(pred, '\t', level);
	pred[level] = '\0';

	buffer = ReadBuffer(r, blk);
	page = (Page) BufferGetPage(buffer);
	opaque = (GISTPageOpaque) PageGetSpecialPointer(page);

	maxoff = PageGetMaxOffsetNumber(page);

	elog(NOTICE, "%sPage: %d %s blk: %d maxoff: %d free: %d", pred,
		 coff, (opaque->flags & F_LEAF) ? "LEAF" : "INTE", (int) blk,
		 (int) maxoff, PageGetFreeSpace(page));

	for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
	{
		iid = PageGetItemId(page, i);
		which = (IndexTuple) PageGetItem(page, iid);
		cblk = ItemPointerGetBlockNumber(&(which->t_tid));
#ifdef PRINTTUPLE
		elog(NOTICE, "%s  Tuple. blk: %d size: %d", pred, (int) cblk,
			 IndexTupleSize(which));
#endif

		if (!(opaque->flags & F_LEAF))
			gist_dumptree(r, level + 1, cblk, i);
	}
	ReleaseBuffer(buffer);
	pfree(pred);
}

#endif	 /* defined GISTDEBUG */

void
gist_redo(XLogRecPtr lsn, XLogRecord *record)
{
	elog(STOP, "gist_redo: unimplemented");
}

void
gist_undo(XLogRecPtr lsn, XLogRecord *record)
{
	elog(STOP, "gist_undo: unimplemented");
}

void
gist_desc(char *buf, uint8 xl_info, char *rec)
{
}
