1 /*-------------------------------------------------------------------------
2  *
3  * tsgistidx.c
4  *	  GiST support functions for tsvector_ops
5  *
6  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
7  *
8  *
9  * IDENTIFICATION
10  *	  src/backend/utils/adt/tsgistidx.c
11  *
12  *-------------------------------------------------------------------------
13  */
14 
15 #include "postgres.h"
16 
17 #include "access/gist.h"
18 #include "access/heaptoast.h"
19 #include "access/reloptions.h"
20 #include "lib/qunique.h"
21 #include "port/pg_bitutils.h"
22 #include "tsearch/ts_utils.h"
23 #include "utils/builtins.h"
24 #include "utils/pg_crc.h"
25 
26 
27 /* tsvector_ops opclass options */
28 typedef struct
29 {
30 	int32		vl_len_;		/* varlena header (do not touch directly!) */
31 	int			siglen;			/* signature length */
32 } GistTsVectorOptions;
33 
34 #define SIGLEN_DEFAULT	(31 * 4)
35 #define SIGLEN_MAX		GISTMaxIndexKeySize
36 #define GET_SIGLEN()	(PG_HAS_OPCLASS_OPTIONS() ? \
37 						 ((GistTsVectorOptions *) PG_GET_OPCLASS_OPTIONS())->siglen : \
38 						 SIGLEN_DEFAULT)
39 
40 #define SIGLENBIT(siglen) ((siglen) * BITS_PER_BYTE)
41 
42 typedef char *BITVECP;
43 
44 #define LOOPBYTE(siglen) \
45 			for (i = 0; i < siglen; i++)
46 
47 #define GETBYTE(x,i) ( *( (BITVECP)(x) + (int)( (i) / BITS_PER_BYTE ) ) )
48 #define GETBITBYTE(x,i) ( ((char)(x)) >> (i) & 0x01 )
49 #define CLRBIT(x,i)   GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITS_PER_BYTE ) )
50 #define SETBIT(x,i)   GETBYTE(x,i) |=  ( 0x01 << ( (i) % BITS_PER_BYTE ) )
51 #define GETBIT(x,i) ( (GETBYTE(x,i) >> ( (i) % BITS_PER_BYTE )) & 0x01 )
52 
53 #define HASHVAL(val, siglen) (((unsigned int)(val)) % SIGLENBIT(siglen))
54 #define HASH(sign, val, siglen) SETBIT((sign), HASHVAL(val, siglen))
55 
56 #define GETENTRY(vec,pos) ((SignTSVector *) DatumGetPointer((vec)->vector[(pos)].key))
57 
58 /*
59  * type of GiST index key
60  */
61 
62 typedef struct
63 {
64 	int32		vl_len_;		/* varlena header (do not touch directly!) */
65 	int32		flag;
66 	char		data[FLEXIBLE_ARRAY_MEMBER];
67 } SignTSVector;
68 
69 #define ARRKEY		0x01
70 #define SIGNKEY		0x02
71 #define ALLISTRUE	0x04
72 
73 #define ISARRKEY(x) ( ((SignTSVector*)(x))->flag & ARRKEY )
74 #define ISSIGNKEY(x)	( ((SignTSVector*)(x))->flag & SIGNKEY )
75 #define ISALLTRUE(x)	( ((SignTSVector*)(x))->flag & ALLISTRUE )
76 
77 #define GTHDRSIZE	( VARHDRSZ + sizeof(int32) )
78 #define CALCGTSIZE(flag, len) ( GTHDRSIZE + ( ( (flag) & ARRKEY ) ? ((len)*sizeof(int32)) : (((flag) & ALLISTRUE) ? 0 : (len)) ) )
79 
80 #define GETSIGN(x)	( (BITVECP)( (char*)(x)+GTHDRSIZE ) )
81 #define GETSIGLEN(x)( VARSIZE(x) - GTHDRSIZE )
82 #define GETARR(x)	( (int32*)( (char*)(x)+GTHDRSIZE ) )
83 #define ARRNELEM(x) ( ( VARSIZE(x) - GTHDRSIZE )/sizeof(int32) )
84 
85 static int32 sizebitvec(BITVECP sign, int siglen);
86 
87 Datum
gtsvectorin(PG_FUNCTION_ARGS)88 gtsvectorin(PG_FUNCTION_ARGS)
89 {
90 	ereport(ERROR,
91 			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
92 			 errmsg("gtsvector_in not implemented")));
93 	PG_RETURN_DATUM(0);
94 }
95 
96 #define SINGOUTSTR	"%d true bits, %d false bits"
97 #define ARROUTSTR	"%d unique words"
98 #define EXTRALEN	( 2*13 )
99 
100 static int	outbuf_maxlen = 0;
101 
102 Datum
gtsvectorout(PG_FUNCTION_ARGS)103 gtsvectorout(PG_FUNCTION_ARGS)
104 {
105 	SignTSVector *key = (SignTSVector *) PG_DETOAST_DATUM(PG_GETARG_POINTER(0));
106 	char	   *outbuf;
107 
108 	if (outbuf_maxlen == 0)
109 		outbuf_maxlen = 2 * EXTRALEN + Max(strlen(SINGOUTSTR), strlen(ARROUTSTR)) + 1;
110 	outbuf = palloc(outbuf_maxlen);
111 
112 	if (ISARRKEY(key))
113 		sprintf(outbuf, ARROUTSTR, (int) ARRNELEM(key));
114 	else
115 	{
116 		int			siglen = GETSIGLEN(key);
117 		int			cnttrue = (ISALLTRUE(key)) ? SIGLENBIT(siglen) : sizebitvec(GETSIGN(key), siglen);
118 
119 		sprintf(outbuf, SINGOUTSTR, cnttrue, (int) SIGLENBIT(siglen) - cnttrue);
120 	}
121 
122 	PG_FREE_IF_COPY(key, 0);
123 	PG_RETURN_POINTER(outbuf);
124 }
125 
126 static int
compareint(const void * va,const void * vb)127 compareint(const void *va, const void *vb)
128 {
129 	int32		a = *((const int32 *) va);
130 	int32		b = *((const int32 *) vb);
131 
132 	if (a == b)
133 		return 0;
134 	return (a > b) ? 1 : -1;
135 }
136 
137 static void
makesign(BITVECP sign,SignTSVector * a,int siglen)138 makesign(BITVECP sign, SignTSVector *a, int siglen)
139 {
140 	int32		k,
141 				len = ARRNELEM(a);
142 	int32	   *ptr = GETARR(a);
143 
144 	MemSet((void *) sign, 0, siglen);
145 	for (k = 0; k < len; k++)
146 		HASH(sign, ptr[k], siglen);
147 }
148 
149 static SignTSVector *
gtsvector_alloc(int flag,int len,BITVECP sign)150 gtsvector_alloc(int flag, int len, BITVECP sign)
151 {
152 	int			size = CALCGTSIZE(flag, len);
153 	SignTSVector *res = palloc(size);
154 
155 	SET_VARSIZE(res, size);
156 	res->flag = flag;
157 
158 	if ((flag & (SIGNKEY | ALLISTRUE)) == SIGNKEY && sign)
159 		memcpy(GETSIGN(res), sign, len);
160 
161 	return res;
162 }
163 
164 
165 Datum
gtsvector_compress(PG_FUNCTION_ARGS)166 gtsvector_compress(PG_FUNCTION_ARGS)
167 {
168 	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
169 	int			siglen = GET_SIGLEN();
170 	GISTENTRY  *retval = entry;
171 
172 	if (entry->leafkey)
173 	{							/* tsvector */
174 		TSVector	val = DatumGetTSVector(entry->key);
175 		SignTSVector *res = gtsvector_alloc(ARRKEY, val->size, NULL);
176 		int32		len;
177 		int32	   *arr;
178 		WordEntry  *ptr = ARRPTR(val);
179 		char	   *words = STRPTR(val);
180 
181 		arr = GETARR(res);
182 		len = val->size;
183 		while (len--)
184 		{
185 			pg_crc32	c;
186 
187 			INIT_LEGACY_CRC32(c);
188 			COMP_LEGACY_CRC32(c, words + ptr->pos, ptr->len);
189 			FIN_LEGACY_CRC32(c);
190 
191 			*arr = *(int32 *) &c;
192 			arr++;
193 			ptr++;
194 		}
195 
196 		qsort(GETARR(res), val->size, sizeof(int), compareint);
197 		len = qunique(GETARR(res), val->size, sizeof(int), compareint);
198 		if (len != val->size)
199 		{
200 			/*
201 			 * there is a collision of hash-function; len is always less than
202 			 * val->size
203 			 */
204 			len = CALCGTSIZE(ARRKEY, len);
205 			res = (SignTSVector *) repalloc((void *) res, len);
206 			SET_VARSIZE(res, len);
207 		}
208 
209 		/* make signature, if array is too long */
210 		if (VARSIZE(res) > TOAST_INDEX_TARGET)
211 		{
212 			SignTSVector *ressign = gtsvector_alloc(SIGNKEY, siglen, NULL);
213 
214 			makesign(GETSIGN(ressign), res, siglen);
215 			res = ressign;
216 		}
217 
218 		retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
219 		gistentryinit(*retval, PointerGetDatum(res),
220 					  entry->rel, entry->page,
221 					  entry->offset, false);
222 	}
223 	else if (ISSIGNKEY(DatumGetPointer(entry->key)) &&
224 			 !ISALLTRUE(DatumGetPointer(entry->key)))
225 	{
226 		int32		i;
227 		SignTSVector *res;
228 		BITVECP		sign = GETSIGN(DatumGetPointer(entry->key));
229 
230 		LOOPBYTE(siglen)
231 		{
232 			if ((sign[i] & 0xff) != 0xff)
233 				PG_RETURN_POINTER(retval);
234 		}
235 
236 		res = gtsvector_alloc(SIGNKEY | ALLISTRUE, siglen, sign);
237 		retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
238 		gistentryinit(*retval, PointerGetDatum(res),
239 					  entry->rel, entry->page,
240 					  entry->offset, false);
241 	}
242 	PG_RETURN_POINTER(retval);
243 }
244 
245 Datum
gtsvector_decompress(PG_FUNCTION_ARGS)246 gtsvector_decompress(PG_FUNCTION_ARGS)
247 {
248 	/*
249 	 * We need to detoast the stored value, because the other gtsvector
250 	 * support functions don't cope with toasted values.
251 	 */
252 	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
253 	SignTSVector *key = (SignTSVector *) PG_DETOAST_DATUM(entry->key);
254 
255 	if (key != (SignTSVector *) DatumGetPointer(entry->key))
256 	{
257 		GISTENTRY  *retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
258 
259 		gistentryinit(*retval, PointerGetDatum(key),
260 					  entry->rel, entry->page,
261 					  entry->offset, false);
262 
263 		PG_RETURN_POINTER(retval);
264 	}
265 
266 	PG_RETURN_POINTER(entry);
267 }
268 
269 typedef struct
270 {
271 	int32	   *arrb;
272 	int32	   *arre;
273 } CHKVAL;
274 
275 /*
276  * TS_execute callback for matching a tsquery operand to GIST leaf-page data
277  */
278 static TSTernaryValue
checkcondition_arr(void * checkval,QueryOperand * val,ExecPhraseData * data)279 checkcondition_arr(void *checkval, QueryOperand *val, ExecPhraseData *data)
280 {
281 	int32	   *StopLow = ((CHKVAL *) checkval)->arrb;
282 	int32	   *StopHigh = ((CHKVAL *) checkval)->arre;
283 	int32	   *StopMiddle;
284 
285 	/* Loop invariant: StopLow <= val < StopHigh */
286 
287 	/*
288 	 * we are not able to find a prefix by hash value
289 	 */
290 	if (val->prefix)
291 		return TS_MAYBE;
292 
293 	while (StopLow < StopHigh)
294 	{
295 		StopMiddle = StopLow + (StopHigh - StopLow) / 2;
296 		if (*StopMiddle == val->valcrc)
297 			return TS_MAYBE;
298 		else if (*StopMiddle < val->valcrc)
299 			StopLow = StopMiddle + 1;
300 		else
301 			StopHigh = StopMiddle;
302 	}
303 
304 	return TS_NO;
305 }
306 
307 /*
308  * TS_execute callback for matching a tsquery operand to GIST non-leaf data
309  */
310 static TSTernaryValue
checkcondition_bit(void * checkval,QueryOperand * val,ExecPhraseData * data)311 checkcondition_bit(void *checkval, QueryOperand *val, ExecPhraseData *data)
312 {
313 	void	   *key = (SignTSVector *) checkval;
314 
315 	/*
316 	 * we are not able to find a prefix in signature tree
317 	 */
318 	if (val->prefix)
319 		return TS_MAYBE;
320 
321 	if (GETBIT(GETSIGN(key), HASHVAL(val->valcrc, GETSIGLEN(key))))
322 		return TS_MAYBE;
323 	else
324 		return TS_NO;
325 }
326 
327 Datum
gtsvector_consistent(PG_FUNCTION_ARGS)328 gtsvector_consistent(PG_FUNCTION_ARGS)
329 {
330 	GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
331 	TSQuery		query = PG_GETARG_TSQUERY(1);
332 
333 	/* StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2); */
334 	/* Oid		subtype = PG_GETARG_OID(3); */
335 	bool	   *recheck = (bool *) PG_GETARG_POINTER(4);
336 	SignTSVector *key = (SignTSVector *) DatumGetPointer(entry->key);
337 
338 	/* All cases served by this function are inexact */
339 	*recheck = true;
340 
341 	if (!query->size)
342 		PG_RETURN_BOOL(false);
343 
344 	if (ISSIGNKEY(key))
345 	{
346 		if (ISALLTRUE(key))
347 			PG_RETURN_BOOL(true);
348 
349 		PG_RETURN_BOOL(TS_execute(GETQUERY(query),
350 								  key,
351 								  TS_EXEC_PHRASE_NO_POS,
352 								  checkcondition_bit));
353 	}
354 	else
355 	{							/* only leaf pages */
356 		CHKVAL		chkval;
357 
358 		chkval.arrb = GETARR(key);
359 		chkval.arre = chkval.arrb + ARRNELEM(key);
360 		PG_RETURN_BOOL(TS_execute(GETQUERY(query),
361 								  (void *) &chkval,
362 								  TS_EXEC_PHRASE_NO_POS,
363 								  checkcondition_arr));
364 	}
365 }
366 
367 static int32
unionkey(BITVECP sbase,SignTSVector * add,int siglen)368 unionkey(BITVECP sbase, SignTSVector *add, int siglen)
369 {
370 	int32		i;
371 
372 	if (ISSIGNKEY(add))
373 	{
374 		BITVECP		sadd = GETSIGN(add);
375 
376 		if (ISALLTRUE(add))
377 			return 1;
378 
379 		Assert(GETSIGLEN(add) == siglen);
380 
381 		LOOPBYTE(siglen)
382 			sbase[i] |= sadd[i];
383 	}
384 	else
385 	{
386 		int32	   *ptr = GETARR(add);
387 
388 		for (i = 0; i < ARRNELEM(add); i++)
389 			HASH(sbase, ptr[i], siglen);
390 	}
391 	return 0;
392 }
393 
394 
395 Datum
gtsvector_union(PG_FUNCTION_ARGS)396 gtsvector_union(PG_FUNCTION_ARGS)
397 {
398 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
399 	int		   *size = (int *) PG_GETARG_POINTER(1);
400 	int			siglen = GET_SIGLEN();
401 	SignTSVector *result = gtsvector_alloc(SIGNKEY, siglen, NULL);
402 	BITVECP		base = GETSIGN(result);
403 	int32		i;
404 
405 	memset(base, 0, siglen);
406 
407 	for (i = 0; i < entryvec->n; i++)
408 	{
409 		if (unionkey(base, GETENTRY(entryvec, i), siglen))
410 		{
411 			result->flag |= ALLISTRUE;
412 			SET_VARSIZE(result, CALCGTSIZE(result->flag, siglen));
413 			break;
414 		}
415 	}
416 
417 	*size = VARSIZE(result);
418 
419 	PG_RETURN_POINTER(result);
420 }
421 
422 Datum
gtsvector_same(PG_FUNCTION_ARGS)423 gtsvector_same(PG_FUNCTION_ARGS)
424 {
425 	SignTSVector *a = (SignTSVector *) PG_GETARG_POINTER(0);
426 	SignTSVector *b = (SignTSVector *) PG_GETARG_POINTER(1);
427 	bool	   *result = (bool *) PG_GETARG_POINTER(2);
428 	int			siglen = GET_SIGLEN();
429 
430 	if (ISSIGNKEY(a))
431 	{							/* then b also ISSIGNKEY */
432 		if (ISALLTRUE(a) && ISALLTRUE(b))
433 			*result = true;
434 		else if (ISALLTRUE(a))
435 			*result = false;
436 		else if (ISALLTRUE(b))
437 			*result = false;
438 		else
439 		{
440 			int32		i;
441 			BITVECP		sa = GETSIGN(a),
442 						sb = GETSIGN(b);
443 
444 			Assert(GETSIGLEN(a) == siglen && GETSIGLEN(b) == siglen);
445 
446 			*result = true;
447 			LOOPBYTE(siglen)
448 			{
449 				if (sa[i] != sb[i])
450 				{
451 					*result = false;
452 					break;
453 				}
454 			}
455 		}
456 	}
457 	else
458 	{							/* a and b ISARRKEY */
459 		int32		lena = ARRNELEM(a),
460 					lenb = ARRNELEM(b);
461 
462 		if (lena != lenb)
463 			*result = false;
464 		else
465 		{
466 			int32	   *ptra = GETARR(a),
467 					   *ptrb = GETARR(b);
468 			int32		i;
469 
470 			*result = true;
471 			for (i = 0; i < lena; i++)
472 				if (ptra[i] != ptrb[i])
473 				{
474 					*result = false;
475 					break;
476 				}
477 		}
478 	}
479 
480 	PG_RETURN_POINTER(result);
481 }
482 
483 static int32
sizebitvec(BITVECP sign,int siglen)484 sizebitvec(BITVECP sign, int siglen)
485 {
486 	return pg_popcount(sign, siglen);
487 }
488 
489 static int
hemdistsign(BITVECP a,BITVECP b,int siglen)490 hemdistsign(BITVECP a, BITVECP b, int siglen)
491 {
492 	int			i,
493 				diff,
494 				dist = 0;
495 
496 	LOOPBYTE(siglen)
497 	{
498 		diff = (unsigned char) (a[i] ^ b[i]);
499 		/* Using the popcount functions here isn't likely to win */
500 		dist += pg_number_of_ones[diff];
501 	}
502 	return dist;
503 }
504 
505 static int
hemdist(SignTSVector * a,SignTSVector * b)506 hemdist(SignTSVector *a, SignTSVector *b)
507 {
508 	int			siglena = GETSIGLEN(a);
509 	int			siglenb = GETSIGLEN(b);
510 
511 	if (ISALLTRUE(a))
512 	{
513 		if (ISALLTRUE(b))
514 			return 0;
515 		else
516 			return SIGLENBIT(siglenb) - sizebitvec(GETSIGN(b), siglenb);
517 	}
518 	else if (ISALLTRUE(b))
519 		return SIGLENBIT(siglena) - sizebitvec(GETSIGN(a), siglena);
520 
521 	Assert(siglena == siglenb);
522 
523 	return hemdistsign(GETSIGN(a), GETSIGN(b), siglena);
524 }
525 
526 Datum
gtsvector_penalty(PG_FUNCTION_ARGS)527 gtsvector_penalty(PG_FUNCTION_ARGS)
528 {
529 	GISTENTRY  *origentry = (GISTENTRY *) PG_GETARG_POINTER(0); /* always ISSIGNKEY */
530 	GISTENTRY  *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
531 	float	   *penalty = (float *) PG_GETARG_POINTER(2);
532 	int			siglen = GET_SIGLEN();
533 	SignTSVector *origval = (SignTSVector *) DatumGetPointer(origentry->key);
534 	SignTSVector *newval = (SignTSVector *) DatumGetPointer(newentry->key);
535 	BITVECP		orig = GETSIGN(origval);
536 
537 	*penalty = 0.0;
538 
539 	if (ISARRKEY(newval))
540 	{
541 		BITVECP		sign = palloc(siglen);
542 
543 		makesign(sign, newval, siglen);
544 
545 		if (ISALLTRUE(origval))
546 		{
547 			int			siglenbit = SIGLENBIT(siglen);
548 
549 			*penalty =
550 				(float) (siglenbit - sizebitvec(sign, siglen)) /
551 				(float) (siglenbit + 1);
552 		}
553 		else
554 			*penalty = hemdistsign(sign, orig, siglen);
555 
556 		pfree(sign);
557 	}
558 	else
559 		*penalty = hemdist(origval, newval);
560 	PG_RETURN_POINTER(penalty);
561 }
562 
563 typedef struct
564 {
565 	bool		allistrue;
566 	BITVECP		sign;
567 } CACHESIGN;
568 
569 static void
fillcache(CACHESIGN * item,SignTSVector * key,int siglen)570 fillcache(CACHESIGN *item, SignTSVector *key, int siglen)
571 {
572 	item->allistrue = false;
573 	if (ISARRKEY(key))
574 		makesign(item->sign, key, siglen);
575 	else if (ISALLTRUE(key))
576 		item->allistrue = true;
577 	else
578 		memcpy((void *) item->sign, (void *) GETSIGN(key), siglen);
579 }
580 
581 #define WISH_F(a,b,c) (double)( -(double)(((a)-(b))*((a)-(b))*((a)-(b)))*(c) )
582 typedef struct
583 {
584 	OffsetNumber pos;
585 	int32		cost;
586 } SPLITCOST;
587 
588 static int
comparecost(const void * va,const void * vb)589 comparecost(const void *va, const void *vb)
590 {
591 	const SPLITCOST *a = (const SPLITCOST *) va;
592 	const SPLITCOST *b = (const SPLITCOST *) vb;
593 
594 	if (a->cost == b->cost)
595 		return 0;
596 	else
597 		return (a->cost > b->cost) ? 1 : -1;
598 }
599 
600 
601 static int
hemdistcache(CACHESIGN * a,CACHESIGN * b,int siglen)602 hemdistcache(CACHESIGN *a, CACHESIGN *b, int siglen)
603 {
604 	if (a->allistrue)
605 	{
606 		if (b->allistrue)
607 			return 0;
608 		else
609 			return SIGLENBIT(siglen) - sizebitvec(b->sign, siglen);
610 	}
611 	else if (b->allistrue)
612 		return SIGLENBIT(siglen) - sizebitvec(a->sign, siglen);
613 
614 	return hemdistsign(a->sign, b->sign, siglen);
615 }
616 
617 Datum
gtsvector_picksplit(PG_FUNCTION_ARGS)618 gtsvector_picksplit(PG_FUNCTION_ARGS)
619 {
620 	GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
621 	GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
622 	int			siglen = GET_SIGLEN();
623 	OffsetNumber k,
624 				j;
625 	SignTSVector *datum_l,
626 			   *datum_r;
627 	BITVECP		union_l,
628 				union_r;
629 	int32		size_alpha,
630 				size_beta;
631 	int32		size_waste,
632 				waste = -1;
633 	int32		nbytes;
634 	OffsetNumber seed_1 = 0,
635 				seed_2 = 0;
636 	OffsetNumber *left,
637 			   *right;
638 	OffsetNumber maxoff;
639 	BITVECP		ptr;
640 	int			i;
641 	CACHESIGN  *cache;
642 	char	   *cache_sign;
643 	SPLITCOST  *costvector;
644 
645 	maxoff = entryvec->n - 2;
646 	nbytes = (maxoff + 2) * sizeof(OffsetNumber);
647 	v->spl_left = (OffsetNumber *) palloc(nbytes);
648 	v->spl_right = (OffsetNumber *) palloc(nbytes);
649 
650 	cache = (CACHESIGN *) palloc(sizeof(CACHESIGN) * (maxoff + 2));
651 	cache_sign = palloc(siglen * (maxoff + 2));
652 
653 	for (j = 0; j < maxoff + 2; j++)
654 		cache[j].sign = &cache_sign[siglen * j];
655 
656 	fillcache(&cache[FirstOffsetNumber], GETENTRY(entryvec, FirstOffsetNumber),
657 			  siglen);
658 
659 	for (k = FirstOffsetNumber; k < maxoff; k = OffsetNumberNext(k))
660 	{
661 		for (j = OffsetNumberNext(k); j <= maxoff; j = OffsetNumberNext(j))
662 		{
663 			if (k == FirstOffsetNumber)
664 				fillcache(&cache[j], GETENTRY(entryvec, j), siglen);
665 
666 			size_waste = hemdistcache(&(cache[j]), &(cache[k]), siglen);
667 			if (size_waste > waste)
668 			{
669 				waste = size_waste;
670 				seed_1 = k;
671 				seed_2 = j;
672 			}
673 		}
674 	}
675 
676 	left = v->spl_left;
677 	v->spl_nleft = 0;
678 	right = v->spl_right;
679 	v->spl_nright = 0;
680 
681 	if (seed_1 == 0 || seed_2 == 0)
682 	{
683 		seed_1 = 1;
684 		seed_2 = 2;
685 	}
686 
687 	/* form initial .. */
688 	datum_l = gtsvector_alloc(SIGNKEY | (cache[seed_1].allistrue ? ALLISTRUE : 0),
689 							  siglen, cache[seed_1].sign);
690 	datum_r = gtsvector_alloc(SIGNKEY | (cache[seed_2].allistrue ? ALLISTRUE : 0),
691 							  siglen, cache[seed_2].sign);
692 	union_l = GETSIGN(datum_l);
693 	union_r = GETSIGN(datum_r);
694 	maxoff = OffsetNumberNext(maxoff);
695 	fillcache(&cache[maxoff], GETENTRY(entryvec, maxoff), siglen);
696 	/* sort before ... */
697 	costvector = (SPLITCOST *) palloc(sizeof(SPLITCOST) * maxoff);
698 	for (j = FirstOffsetNumber; j <= maxoff; j = OffsetNumberNext(j))
699 	{
700 		costvector[j - 1].pos = j;
701 		size_alpha = hemdistcache(&(cache[seed_1]), &(cache[j]), siglen);
702 		size_beta = hemdistcache(&(cache[seed_2]), &(cache[j]), siglen);
703 		costvector[j - 1].cost = Abs(size_alpha - size_beta);
704 	}
705 	qsort((void *) costvector, maxoff, sizeof(SPLITCOST), comparecost);
706 
707 	for (k = 0; k < maxoff; k++)
708 	{
709 		j = costvector[k].pos;
710 		if (j == seed_1)
711 		{
712 			*left++ = j;
713 			v->spl_nleft++;
714 			continue;
715 		}
716 		else if (j == seed_2)
717 		{
718 			*right++ = j;
719 			v->spl_nright++;
720 			continue;
721 		}
722 
723 		if (ISALLTRUE(datum_l) || cache[j].allistrue)
724 		{
725 			if (ISALLTRUE(datum_l) && cache[j].allistrue)
726 				size_alpha = 0;
727 			else
728 				size_alpha = SIGLENBIT(siglen) -
729 					sizebitvec((cache[j].allistrue) ?
730 							   GETSIGN(datum_l) :
731 							   GETSIGN(cache[j].sign),
732 							   siglen);
733 		}
734 		else
735 			size_alpha = hemdistsign(cache[j].sign, GETSIGN(datum_l), siglen);
736 
737 		if (ISALLTRUE(datum_r) || cache[j].allistrue)
738 		{
739 			if (ISALLTRUE(datum_r) && cache[j].allistrue)
740 				size_beta = 0;
741 			else
742 				size_beta = SIGLENBIT(siglen) -
743 					sizebitvec((cache[j].allistrue) ?
744 							   GETSIGN(datum_r) :
745 							   GETSIGN(cache[j].sign),
746 							   siglen);
747 		}
748 		else
749 			size_beta = hemdistsign(cache[j].sign, GETSIGN(datum_r), siglen);
750 
751 		if (size_alpha < size_beta + WISH_F(v->spl_nleft, v->spl_nright, 0.1))
752 		{
753 			if (ISALLTRUE(datum_l) || cache[j].allistrue)
754 			{
755 				if (!ISALLTRUE(datum_l))
756 					MemSet((void *) GETSIGN(datum_l), 0xff, siglen);
757 			}
758 			else
759 			{
760 				ptr = cache[j].sign;
761 				LOOPBYTE(siglen)
762 					union_l[i] |= ptr[i];
763 			}
764 			*left++ = j;
765 			v->spl_nleft++;
766 		}
767 		else
768 		{
769 			if (ISALLTRUE(datum_r) || cache[j].allistrue)
770 			{
771 				if (!ISALLTRUE(datum_r))
772 					MemSet((void *) GETSIGN(datum_r), 0xff, siglen);
773 			}
774 			else
775 			{
776 				ptr = cache[j].sign;
777 				LOOPBYTE(siglen)
778 					union_r[i] |= ptr[i];
779 			}
780 			*right++ = j;
781 			v->spl_nright++;
782 		}
783 	}
784 
785 	*right = *left = FirstOffsetNumber;
786 	v->spl_ldatum = PointerGetDatum(datum_l);
787 	v->spl_rdatum = PointerGetDatum(datum_r);
788 
789 	PG_RETURN_POINTER(v);
790 }
791 
792 /*
793  * Formerly, gtsvector_consistent was declared in pg_proc.h with arguments
794  * that did not match the documented conventions for GiST support functions.
795  * We fixed that, but we still need a pg_proc entry with the old signature
796  * to support reloading pre-9.6 contrib/tsearch2 opclass declarations.
797  * This compatibility function should go away eventually.
798  */
799 Datum
gtsvector_consistent_oldsig(PG_FUNCTION_ARGS)800 gtsvector_consistent_oldsig(PG_FUNCTION_ARGS)
801 {
802 	return gtsvector_consistent(fcinfo);
803 }
804 
805 Datum
gtsvector_options(PG_FUNCTION_ARGS)806 gtsvector_options(PG_FUNCTION_ARGS)
807 {
808 	local_relopts *relopts = (local_relopts *) PG_GETARG_POINTER(0);
809 
810 	init_local_reloptions(relopts, sizeof(GistTsVectorOptions));
811 	add_local_int_reloption(relopts, "siglen", "signature length",
812 							SIGLEN_DEFAULT, 1, SIGLEN_MAX,
813 							offsetof(GistTsVectorOptions, siglen));
814 
815 	PG_RETURN_VOID();
816 }
817