Tsearch2 functionality migrates to core. The bulk of this work is by

Oleg Bartunov and Teodor Sigaev, but I did a lot of editorializing,
so anything that's broken is probably my fault.

Documentation is nonexistent as yet, but let's land the patch so we can
get some portability testing done.

1 files changed, 784 insertions, 0 deletions

diff --git a/src/backend/utils/adt/tsgistidx.c b/src/backend/utils/adt/tsgistidx.c
new file mode 100644
index 00000000000..04c2b4c442f
--- /dev/null
+++ b/src/backend/utils/adt/tsgistidx.c
@@ -0,0 +1,784 @@
+/*-------------------------------------------------------------------------
+ *
+ * tsgistidx.c
+ *	  GiST support functions for tsvector_ops
+ *
+ * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/tsgistidx.c,v 1.1 2007/08/21 01:11:19 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "access/gist.h"
+#include "access/tuptoaster.h"
+#include "tsearch/ts_type.h"
+#include "tsearch/ts_utils.h"
+#include "utils/pg_crc.h"
+
+
+#define SIGLENINT  31			/* >121 => key will toast, so it will not work
+								 * !!! */
+
+#define SIGLEN	( sizeof(int4) * SIGLENINT )
+#define SIGLENBIT (SIGLEN * BITS_PER_BYTE)
+
+typedef char BITVEC[SIGLEN];
+typedef char *BITVECP;
+
+#define LOOPBYTE(a) \
+	for(i=0;i<SIGLEN;i++) {\
+		a;\
+}
+
+#define GETBYTE(x,i) ( *( (BITVECP)(x) + (int)( (i) / BITS_PER_BYTE ) ) )
+#define GETBITBYTE(x,i) ( ((char)(x)) >> (i) & 0x01 )
+#define CLRBIT(x,i)   GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITS_PER_BYTE ) )
+#define SETBIT(x,i)   GETBYTE(x,i) |=  ( 0x01 << ( (i) % BITS_PER_BYTE ) )
+#define GETBIT(x,i) ( (GETBYTE(x,i) >> ( (i) % BITS_PER_BYTE )) & 0x01 )
+
+#define HASHVAL(val) (((unsigned int)(val)) % SIGLENBIT)
+#define HASH(sign, val) SETBIT((sign), HASHVAL(val))
+
+#define GETENTRY(vec,pos) ((SignTSVector *) DatumGetPointer((vec)->vector[(pos)].key))
+
+/*
+ * type of GiST index key
+ */
+
+typedef struct
+{
+	int32		vl_len_; /* varlena header (do not touch directly!) */ ;
+	int4		flag;
+	char		data[1];
+} SignTSVector;
+
+#define ARRKEY		0x01
+#define SIGNKEY		0x02
+#define ALLISTRUE	0x04
+
+#define ISARRKEY(x) ( ((SignTSVector*)(x))->flag & ARRKEY )
+#define ISSIGNKEY(x)	( ((SignTSVector*)(x))->flag & SIGNKEY )
+#define ISALLTRUE(x)	( ((SignTSVector*)(x))->flag & ALLISTRUE )
+
+#define GTHDRSIZE	( VARHDRSZ + sizeof(int4) )
+#define CALCGTSIZE(flag, len) ( GTHDRSIZE + ( ( (flag) & ARRKEY ) ? ((len)*sizeof(int4)) : (((flag) & ALLISTRUE) ? 0 : SIGLEN) ) )
+
+#define GETSIGN(x)	( (BITVECP)( (char*)(x)+GTHDRSIZE ) )
+#define GETARR(x)	( (int4*)( (char*)(x)+GTHDRSIZE ) )
+#define ARRNELEM(x) ( ( VARSIZE(x) - GTHDRSIZE )/sizeof(int4) )
+
+/* Number of one-bits in an unsigned byte */
+static const uint8 number_of_ones[256] = {
+	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
+};
+
+static int4 sizebitvec(BITVECP sign);
+
+Datum
+gtsvectorin(PG_FUNCTION_ARGS)
+{
+	ereport(ERROR,
+			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+			 errmsg("gtsvector_in not implemented")));
+	PG_RETURN_DATUM(0);
+}
+
+#define SINGOUTSTR	"%d true bits, %d false bits"
+#define ARROUTSTR	"%d unique words"
+#define EXTRALEN	( 2*13 )
+
+static int	outbuf_maxlen = 0;
+
+Datum
+gtsvectorout(PG_FUNCTION_ARGS)
+{
+	SignTSVector *key = (SignTSVector *) DatumGetPointer(PG_DETOAST_DATUM(PG_GETARG_POINTER(0)));
+	char	   *outbuf;
+
+	if (outbuf_maxlen == 0)
+		outbuf_maxlen = 2 * EXTRALEN + Max(strlen(SINGOUTSTR), strlen(ARROUTSTR)) + 1;
+	outbuf = palloc(outbuf_maxlen);
+
+	if (ISARRKEY(key))
+		sprintf(outbuf, ARROUTSTR, (int) ARRNELEM(key));
+	else
+	{
+		int			cnttrue = (ISALLTRUE(key)) ? SIGLENBIT : sizebitvec(GETSIGN(key));
+
+		sprintf(outbuf, SINGOUTSTR, cnttrue, (int) SIGLENBIT - cnttrue);
+	}
+
+	PG_FREE_IF_COPY(key, 0);
+	PG_RETURN_POINTER(outbuf);
+}
+
+static int
+compareint(const void *a, const void *b)
+{
+	if (*((int4 *) a) == *((int4 *) b))
+		return 0;
+	return (*((int4 *) a) > *((int4 *) b)) ? 1 : -1;
+}
+
+static int
+uniqueint(int4 *a, int4 l)
+{
+	int4	   *ptr,
+			   *res;
+
+	if (l == 1)
+		return l;
+
+	ptr = res = a;
+
+	qsort((void *) a, l, sizeof(int4), compareint);
+
+	while (ptr - a < l)
+		if (*ptr != *res)
+			*(++res) = *ptr++;
+		else
+			ptr++;
+	return res + 1 - a;
+}
+
+static void
+makesign(BITVECP sign, SignTSVector * a)
+{
+	int4		k,
+				len = ARRNELEM(a);
+	int4	   *ptr = GETARR(a);
+
+	MemSet((void *) sign, 0, sizeof(BITVEC));
+	for (k = 0; k < len; k++)
+		HASH(sign, ptr[k]);
+}
+
+Datum
+gtsvector_compress(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	GISTENTRY  *retval = entry;
+
+	if (entry->leafkey)
+	{							/* tsvector */
+		SignTSVector *res;
+		TSVector	val = DatumGetTSVector(entry->key);
+		int4		len;
+		int4	   *arr;
+		WordEntry  *ptr = ARRPTR(val);
+		char	   *words = STRPTR(val);
+
+		len = CALCGTSIZE(ARRKEY, val->size);
+		res = (SignTSVector *) palloc(len);
+		SET_VARSIZE(res, len);
+		res->flag = ARRKEY;
+		arr = GETARR(res);
+		len = val->size;
+		while (len--)
+		{
+			pg_crc32	c;
+
+			INIT_CRC32(c);
+			COMP_CRC32(c, words + ptr->pos, ptr->len);
+			FIN_CRC32(c);
+
+			*arr = *(int4 *) &c;
+			arr++;
+			ptr++;
+		}
+
+		len = uniqueint(GETARR(res), val->size);
+		if (len != val->size)
+		{
+			/*
+			 * there is a collision of hash-function; len is always less than
+			 * val->size
+			 */
+			len = CALCGTSIZE(ARRKEY, len);
+			res = (SignTSVector *) repalloc((void *) res, len);
+			SET_VARSIZE(res, len);
+		}
+
+		/* make signature, if array is too long */
+		if (VARSIZE(res) > TOAST_INDEX_TARGET)
+		{
+			SignTSVector *ressign;
+
+			len = CALCGTSIZE(SIGNKEY, 0);
+			ressign = (SignTSVector *) palloc(len);
+			SET_VARSIZE(ressign, len);
+			ressign->flag = SIGNKEY;
+			makesign(GETSIGN(ressign), res);
+			res = ressign;
+		}
+
+		retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
+		gistentryinit(*retval, PointerGetDatum(res),
+					  entry->rel, entry->page,
+					  entry->offset, FALSE);
+	}
+	else if (ISSIGNKEY(DatumGetPointer(entry->key)) &&
+			 !ISALLTRUE(DatumGetPointer(entry->key)))
+	{
+		int4		i,
+					len;
+		SignTSVector *res;
+		BITVECP		sign = GETSIGN(DatumGetPointer(entry->key));
+
+		LOOPBYTE(
+				 if ((sign[i] & 0xff) != 0xff)
+				 PG_RETURN_POINTER(retval);
+		);
+
+		len = CALCGTSIZE(SIGNKEY | ALLISTRUE, 0);
+		res = (SignTSVector *) palloc(len);
+		SET_VARSIZE(res, len);
+		res->flag = SIGNKEY | ALLISTRUE;
+
+		retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
+		gistentryinit(*retval, PointerGetDatum(res),
+					  entry->rel, entry->page,
+					  entry->offset, FALSE);
+	}
+	PG_RETURN_POINTER(retval);
+}
+
+Datum
+gtsvector_decompress(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
+	SignTSVector *key = (SignTSVector *) DatumGetPointer(PG_DETOAST_DATUM(entry->key));
+
+	if (key != (SignTSVector *) DatumGetPointer(entry->key))
+	{
+		GISTENTRY  *retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
+
+		gistentryinit(*retval, PointerGetDatum(key),
+					  entry->rel, entry->page,
+					  entry->offset, FALSE);
+
+		PG_RETURN_POINTER(retval);
+	}
+
+	PG_RETURN_POINTER(entry);
+}
+
+typedef struct
+{
+	int4	   *arrb;
+	int4	   *arre;
+} CHKVAL;
+
+/*
+ * is there value 'val' in array or not ?
+ */
+static bool
+checkcondition_arr(void *checkval, QueryItem * val)
+{
+	int4	   *StopLow = ((CHKVAL *) checkval)->arrb;
+	int4	   *StopHigh = ((CHKVAL *) checkval)->arre;
+	int4	   *StopMiddle;
+
+	/* Loop invariant: StopLow <= val < StopHigh */
+
+	while (StopLow < StopHigh)
+	{
+		StopMiddle = StopLow + (StopHigh - StopLow) / 2;
+		if (*StopMiddle == val->val)
+			return (true);
+		else if (*StopMiddle < val->val)
+			StopLow = StopMiddle + 1;
+		else
+			StopHigh = StopMiddle;
+	}
+
+	return (false);
+}
+
+static bool
+checkcondition_bit(void *checkval, QueryItem * val)
+{
+	return GETBIT(checkval, HASHVAL(val->val));
+}
+
+Datum
+gtsvector_consistent(PG_FUNCTION_ARGS)
+{
+	TSQuery		query = PG_GETARG_TSQUERY(1);
+	SignTSVector *key = (SignTSVector *) DatumGetPointer(
+									((GISTENTRY *) PG_GETARG_POINTER(0))->key
+	);
+
+	if (!query->size)
+		PG_RETURN_BOOL(false);
+
+	if (ISSIGNKEY(key))
+	{
+		if (ISALLTRUE(key))
+			PG_RETURN_BOOL(true);
+
+		PG_RETURN_BOOL(TS_execute(
+								  GETQUERY(query),
+								  (void *) GETSIGN(key), false,
+								  checkcondition_bit
+								  ));
+	}
+	else
+	{							/* only leaf pages */
+		CHKVAL		chkval;
+
+		chkval.arrb = GETARR(key);
+		chkval.arre = chkval.arrb + ARRNELEM(key);
+		PG_RETURN_BOOL(TS_execute(
+								  GETQUERY(query),
+								  (void *) &chkval, true,
+								  checkcondition_arr
+								  ));
+	}
+}
+
+static int4
+unionkey(BITVECP sbase, SignTSVector * add)
+{
+	int4		i;
+
+	if (ISSIGNKEY(add))
+	{
+		BITVECP		sadd = GETSIGN(add);
+
+		if (ISALLTRUE(add))
+			return 1;
+
+		LOOPBYTE(
+				 sbase[i] |= sadd[i];
+		);
+	}
+	else
+	{
+		int4	   *ptr = GETARR(add);
+
+		for (i = 0; i < ARRNELEM(add); i++)
+			HASH(sbase, ptr[i]);
+	}
+	return 0;
+}
+
+
+Datum
+gtsvector_union(PG_FUNCTION_ARGS)
+{
+	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
+	int		   *size = (int *) PG_GETARG_POINTER(1);
+	BITVEC		base;
+	int4		i,
+				len;
+	int4		flag = 0;
+	SignTSVector *result;
+
+	MemSet((void *) base, 0, sizeof(BITVEC));
+	for (i = 0; i < entryvec->n; i++)
+	{
+		if (unionkey(base, GETENTRY(entryvec, i)))
+		{
+			flag = ALLISTRUE;
+			break;
+		}
+	}
+
+	flag |= SIGNKEY;
+	len = CALCGTSIZE(flag, 0);
+	result = (SignTSVector *) palloc(len);
+	*size = len;
+	SET_VARSIZE(result, len);
+	result->flag = flag;
+	if (!ISALLTRUE(result))
+		memcpy((void *) GETSIGN(result), (void *) base, sizeof(BITVEC));
+
+	PG_RETURN_POINTER(result);
+}
+
+Datum
+gtsvector_same(PG_FUNCTION_ARGS)
+{
+	SignTSVector *a = (SignTSVector *) PG_GETARG_POINTER(0);
+	SignTSVector *b = (SignTSVector *) PG_GETARG_POINTER(1);
+	bool	   *result = (bool *) PG_GETARG_POINTER(2);
+
+	if (ISSIGNKEY(a))
+	{							/* then b also ISSIGNKEY */
+		if (ISALLTRUE(a) && ISALLTRUE(b))
+			*result = true;
+		else if (ISALLTRUE(a))
+			*result = false;
+		else if (ISALLTRUE(b))
+			*result = false;
+		else
+		{
+			int4		i;
+			BITVECP		sa = GETSIGN(a),
+						sb = GETSIGN(b);
+
+			*result = true;
+			LOOPBYTE(
+					 if (sa[i] != sb[i])
+					 {
+				*result = false;
+				break;
+			}
+			);
+		}
+	}
+	else
+	{							/* a and b ISARRKEY */
+		int4		lena = ARRNELEM(a),
+					lenb = ARRNELEM(b);
+
+		if (lena != lenb)
+			*result = false;
+		else
+		{
+			int4	   *ptra = GETARR(a),
+					   *ptrb = GETARR(b);
+			int4		i;
+
+			*result = true;
+			for (i = 0; i < lena; i++)
+				if (ptra[i] != ptrb[i])
+				{
+					*result = false;
+					break;
+				}
+		}
+	}
+
+	PG_RETURN_POINTER(result);
+}
+
+static int4
+sizebitvec(BITVECP sign)
+{
+	int4		size = 0,
+				i;
+
+	LOOPBYTE(
+			 size += number_of_ones[(unsigned char) sign[i]];
+	);
+	return size;
+}
+
+static int
+hemdistsign(BITVECP a, BITVECP b)
+{
+	int			i,
+				diff,
+				dist = 0;
+
+	LOOPBYTE(
+			 diff = (unsigned char) (a[i] ^ b[i]);
+	dist += number_of_ones[diff];
+	);
+	return dist;
+}
+
+static int
+hemdist(SignTSVector * a, SignTSVector * b)
+{
+	if (ISALLTRUE(a))
+	{
+		if (ISALLTRUE(b))
+			return 0;
+		else
+			return SIGLENBIT - sizebitvec(GETSIGN(b));
+	}
+	else if (ISALLTRUE(b))
+		return SIGLENBIT - sizebitvec(GETSIGN(a));
+
+	return hemdistsign(GETSIGN(a), GETSIGN(b));
+}
+
+Datum
+gtsvector_penalty(PG_FUNCTION_ARGS)
+{
+	GISTENTRY  *origentry = (GISTENTRY *) PG_GETARG_POINTER(0); /* always ISSIGNKEY */
+	GISTENTRY  *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
+	float	   *penalty = (float *) PG_GETARG_POINTER(2);
+	SignTSVector *origval = (SignTSVector *) DatumGetPointer(origentry->key);
+	SignTSVector *newval = (SignTSVector *) DatumGetPointer(newentry->key);
+	BITVECP		orig = GETSIGN(origval);
+
+	*penalty = 0.0;
+
+	if (ISARRKEY(newval))
+	{
+		BITVEC		sign;
+
+		makesign(sign, newval);
+
+		if (ISALLTRUE(origval))
+			*penalty = ((float) (SIGLENBIT - sizebitvec(sign))) / (float) (SIGLENBIT + 1);
+		else
+			*penalty = hemdistsign(sign, orig);
+	}
+	else
+		*penalty = hemdist(origval, newval);
+	PG_RETURN_POINTER(penalty);
+}
+
+typedef struct
+{
+	bool		allistrue;
+	BITVEC		sign;
+} CACHESIGN;
+
+static void
+fillcache(CACHESIGN * item, SignTSVector * key)
+{
+	item->allistrue = false;
+	if (ISARRKEY(key))
+		makesign(item->sign, key);
+	else if (ISALLTRUE(key))
+		item->allistrue = true;
+	else
+		memcpy((void *) item->sign, (void *) GETSIGN(key), sizeof(BITVEC));
+}
+
+#define WISH_F(a,b,c) (double)( -(double)(((a)-(b))*((a)-(b))*((a)-(b)))*(c) )
+typedef struct
+{
+	OffsetNumber pos;
+	int4		cost;
+} SPLITCOST;
+
+static int
+comparecost(const void *a, const void *b)
+{
+	if (((SPLITCOST *) a)->cost == ((SPLITCOST *) b)->cost)
+		return 0;
+	else
+		return (((SPLITCOST *) a)->cost > ((SPLITCOST *) b)->cost) ? 1 : -1;
+}
+
+
+static int
+hemdistcache(CACHESIGN * a, CACHESIGN * b)
+{
+	if (a->allistrue)
+	{
+		if (b->allistrue)
+			return 0;
+		else
+			return SIGLENBIT - sizebitvec(b->sign);
+	}
+	else if (b->allistrue)
+		return SIGLENBIT - sizebitvec(a->sign);
+
+	return hemdistsign(a->sign, b->sign);
+}
+
+Datum
+gtsvector_picksplit(PG_FUNCTION_ARGS)
+{
+	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
+	GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
+	OffsetNumber k,
+				j;
+	SignTSVector *datum_l,
+			   *datum_r;
+	BITVECP		union_l,
+				union_r;
+	int4		size_alpha,
+				size_beta;
+	int4		size_waste,
+				waste = -1;
+	int4		nbytes;
+	OffsetNumber seed_1 = 0,
+				seed_2 = 0;
+	OffsetNumber *left,
+			   *right;
+	OffsetNumber maxoff;
+	BITVECP		ptr;
+	int			i;
+	CACHESIGN  *cache;
+	SPLITCOST  *costvector;
+
+	maxoff = entryvec->n - 2;
+	nbytes = (maxoff + 2) * sizeof(OffsetNumber);
+	v->spl_left = (OffsetNumber *) palloc(nbytes);
+	v->spl_right = (OffsetNumber *) palloc(nbytes);
+
+	cache = (CACHESIGN *) palloc(sizeof(CACHESIGN) * (maxoff + 2));
+	fillcache(&cache[FirstOffsetNumber], GETENTRY(entryvec, FirstOffsetNumber));
+
+	for (k = FirstOffsetNumber; k < maxoff; k = OffsetNumberNext(k))
+	{
+		for (j = OffsetNumberNext(k); j <= maxoff; j = OffsetNumberNext(j))
+		{
+			if (k == FirstOffsetNumber)
+				fillcache(&cache[j], GETENTRY(entryvec, j));
+
+			size_waste = hemdistcache(&(cache[j]), &(cache[k]));
+			if (size_waste > waste)
+			{
+				waste = size_waste;
+				seed_1 = k;
+				seed_2 = j;
+			}
+		}
+	}
+
+	left = v->spl_left;
+	v->spl_nleft = 0;
+	right = v->spl_right;
+	v->spl_nright = 0;
+
+	if (seed_1 == 0 || seed_2 == 0)
+	{
+		seed_1 = 1;
+		seed_2 = 2;
+	}
+
+	/* form initial .. */
+	if (cache[seed_1].allistrue)
+	{
+		datum_l = (SignTSVector *) palloc(CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
+		SET_VARSIZE(datum_l, CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
+		datum_l->flag = SIGNKEY | ALLISTRUE;
+	}
+	else
+	{
+		datum_l = (SignTSVector *) palloc(CALCGTSIZE(SIGNKEY, 0));
+		SET_VARSIZE(datum_l, CALCGTSIZE(SIGNKEY, 0));
+		datum_l->flag = SIGNKEY;
+		memcpy((void *) GETSIGN(datum_l), (void *) cache[seed_1].sign, sizeof(BITVEC));
+	}
+	if (cache[seed_2].allistrue)
+	{
+		datum_r = (SignTSVector *) palloc(CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
+		SET_VARSIZE(datum_r, CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
+		datum_r->flag = SIGNKEY | ALLISTRUE;
+	}
+	else
+	{
+		datum_r = (SignTSVector *) palloc(CALCGTSIZE(SIGNKEY, 0));
+		SET_VARSIZE(datum_r, CALCGTSIZE(SIGNKEY, 0));
+		datum_r->flag = SIGNKEY;
+		memcpy((void *) GETSIGN(datum_r), (void *) cache[seed_2].sign, sizeof(BITVEC));
+	}
+
+	union_l = GETSIGN(datum_l);
+	union_r = GETSIGN(datum_r);
+	maxoff = OffsetNumberNext(maxoff);
+	fillcache(&cache[maxoff], GETENTRY(entryvec, maxoff));
+	/* sort before ... */
+	costvector = (SPLITCOST *) palloc(sizeof(SPLITCOST) * maxoff);
+	for (j = FirstOffsetNumber; j <= maxoff; j = OffsetNumberNext(j))
+	{
+		costvector[j - 1].pos = j;
+		size_alpha = hemdistcache(&(cache[seed_1]), &(cache[j]));
+		size_beta = hemdistcache(&(cache[seed_2]), &(cache[j]));
+		costvector[j - 1].cost = Abs(size_alpha - size_beta);
+	}
+	qsort((void *) costvector, maxoff, sizeof(SPLITCOST), comparecost);
+
+	for (k = 0; k < maxoff; k++)
+	{
+		j = costvector[k].pos;
+		if (j == seed_1)
+		{
+			*left++ = j;
+			v->spl_nleft++;
+			continue;
+		}
+		else if (j == seed_2)
+		{
+			*right++ = j;
+			v->spl_nright++;
+			continue;
+		}
+
+		if (ISALLTRUE(datum_l) || cache[j].allistrue)
+		{
+			if (ISALLTRUE(datum_l) && cache[j].allistrue)
+				size_alpha = 0;
+			else
+				size_alpha = SIGLENBIT - sizebitvec(
+													(cache[j].allistrue) ? GETSIGN(datum_l) : GETSIGN(cache[j].sign)
+					);
+		}
+		else
+			size_alpha = hemdistsign(cache[j].sign, GETSIGN(datum_l));
+
+		if (ISALLTRUE(datum_r) || cache[j].allistrue)
+		{
+			if (ISALLTRUE(datum_r) && cache[j].allistrue)
+				size_beta = 0;
+			else
+				size_beta = SIGLENBIT - sizebitvec(
+												   (cache[j].allistrue) ? GETSIGN(datum_r) : GETSIGN(cache[j].sign)
+					);
+		}
+		else
+			size_beta = hemdistsign(cache[j].sign, GETSIGN(datum_r));
+
+		if (size_alpha < size_beta + WISH_F(v->spl_nleft, v->spl_nright, 0.1))
+		{
+			if (ISALLTRUE(datum_l) || cache[j].allistrue)
+			{
+				if (!ISALLTRUE(datum_l))
+					MemSet((void *) GETSIGN(datum_l), 0xff, sizeof(BITVEC));
+			}
+			else
+			{
+				ptr = cache[j].sign;
+				LOOPBYTE(
+						 union_l[i] |= ptr[i];
+				);
+			}
+			*left++ = j;
+			v->spl_nleft++;
+		}
+		else
+		{
+			if (ISALLTRUE(datum_r) || cache[j].allistrue)
+			{
+				if (!ISALLTRUE(datum_r))
+					MemSet((void *) GETSIGN(datum_r), 0xff, sizeof(BITVEC));
+			}
+			else
+			{
+				ptr = cache[j].sign;
+				LOOPBYTE(
+						 union_r[i] |= ptr[i];
+				);
+			}
+			*right++ = j;
+			v->spl_nright++;
+		}
+	}
+
+	*right = *left = FirstOffsetNumber;
+	v->spl_ldatum = PointerGetDatum(datum_l);
+	v->spl_rdatum = PointerGetDatum(datum_r);
+
+	PG_RETURN_POINTER(v);
+}