postgresql/contrib/pg_trgm/trgm_gist.c
Teodor Sigaev cbfa4092bb trgm - Trigram matching for PostgreSQL
--------------------------------------

	The pg_trgm contrib module provides functions and index classes
	for determining the similarity of text based on trigram
	matching.
2004-05-31 17:18:12 +00:00

567 lines
13 KiB
C

#include "trgm.h"
#include "access/gist.h"
#include "access/itup.h"
#include "access/rtree.h"
#include "utils/elog.h"
#include "utils/palloc.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "storage/bufpage.h"
#include "access/tuptoaster.h"
PG_FUNCTION_INFO_V1(gtrgm_in);
Datum gtrgm_in(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_out);
Datum gtrgm_out(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_compress);
Datum gtrgm_compress(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_decompress);
Datum gtrgm_decompress(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_consistent);
Datum gtrgm_consistent(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_union);
Datum gtrgm_union(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_same);
Datum gtrgm_same(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_penalty);
Datum gtrgm_penalty(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(gtrgm_picksplit);
Datum gtrgm_picksplit(PG_FUNCTION_ARGS);
#define GETENTRY(vec,pos) ((TRGM *) DatumGetPointer((vec)->vector[(pos)].key))
#define SUMBIT(val) ( \
GETBITBYTE(val,0) + \
GETBITBYTE(val,1) + \
GETBITBYTE(val,2) + \
GETBITBYTE(val,3) + \
GETBITBYTE(val,4) + \
GETBITBYTE(val,5) + \
GETBITBYTE(val,6) + \
GETBITBYTE(val,7) \
)
Datum
gtrgm_in(PG_FUNCTION_ARGS)
{
elog(ERROR, "Not implemented");
PG_RETURN_DATUM(0);
}
Datum
gtrgm_out(PG_FUNCTION_ARGS)
{
elog(ERROR, "Not implemented");
PG_RETURN_DATUM(0);
}
static void
makesign(BITVECP sign, TRGM * a)
{
int4 k,
len = ARRNELEM(a);
trgm *ptr = GETARR(a);
int4 tmp=0;
MemSet((void *) sign, 0, sizeof(BITVEC));
SETBIT(sign, SIGLENBIT); /*set last unused bit*/
for (k = 0; k < len; k++) {
CPTRGM( ((char*)&tmp), ptr+k );
HASH(sign, tmp);
}
}
Datum
gtrgm_compress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval = entry;
if (entry->leafkey)
{ /* trgm */
TRGM *res;
text *toastedval = (text *) DatumGetPointer(entry->key);
text *val = (text *) DatumGetPointer(PG_DETOAST_DATUM(entry->key));
res = generate_trgm(VARDATA(val), VARSIZE(val) - VARHDRSZ);
if (val != toastedval)
pfree(val);
retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(res),
entry->rel, entry->page,
entry->offset, res->len, FALSE);
}
else if (ISSIGNKEY(DatumGetPointer(entry->key)) &&
!ISALLTRUE(DatumGetPointer(entry->key)))
{
int4 i,
len;
TRGM *res;
BITVECP sign = GETSIGN(DatumGetPointer(entry->key));
LOOPBYTE(
if ((sign[i] & 0xff) != 0xff)
PG_RETURN_POINTER(retval);
);
len = CALCGTSIZE(SIGNKEY | ALLISTRUE, 0);
res = (TRGM *) palloc(len);
res->len = len;
res->flag = SIGNKEY | ALLISTRUE;
retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(res),
entry->rel, entry->page,
entry->offset, res->len, FALSE);
}
PG_RETURN_POINTER(retval);
}
Datum
gtrgm_decompress(PG_FUNCTION_ARGS)
{
PG_RETURN_DATUM(PG_GETARG_DATUM(0));
}
Datum
gtrgm_consistent(PG_FUNCTION_ARGS)
{
text *query = (text *) PG_GETARG_TEXT_P(1);
TRGM *key = (TRGM *) DatumGetPointer( ((GISTENTRY *) PG_GETARG_POINTER(0))->key );
TRGM *qtrg = generate_trgm(VARDATA(query), VARSIZE(query) - VARHDRSZ);
int res=false;
if ( GIST_LEAF( (GISTENTRY *) PG_GETARG_POINTER(0) ) ) { /* all leafs contains orig trgm */
float4 tmpsml = cnt_sml(key,qtrg);
/* strange bug at freebsd 5.2.1 and gcc 3.3.3 */
res = ( *(int*)&tmpsml==*(int*)&trgm_limit || tmpsml > trgm_limit ) ? true : false;
} else if ( ISALLTRUE(key) ) { /* non-leaf contains signature */
res = true;
} else { /* non-leaf contains signature */
int4 count=0;
int4 k, len = ARRNELEM(qtrg);
trgm *ptr = GETARR(qtrg);
BITVECP sign = GETSIGN(key);
int4 tmp=0;
for (k = 0; k < len; k++) {
CPTRGM( ((char*)&tmp), ptr+k );
count += GETBIT(sign, HASHVAL(tmp));
}
#ifdef DIVUNION
res = ( len==count ) ? true : ( ( ( ( ((float4)count) / ((float4)(len-count)) ) ) >= trgm_limit ) ? true : false );
#else
res = (len==0) ? false : ( ( ( ( ((float4)count) / ((float4)len) ) ) >= trgm_limit ) ? true : false );
#endif
}
PG_FREE_IF_COPY(query,1);
pfree(qtrg);
PG_RETURN_BOOL(res);
}
static int4
unionkey(BITVECP sbase, TRGM * add)
{
int4 i;
if (ISSIGNKEY(add))
{
BITVECP sadd = GETSIGN(add);
if (ISALLTRUE(add))
return 1;
LOOPBYTE(
sbase[i] |= sadd[i];
);
}
else
{
trgm *ptr = GETARR(add);
int4 tmp=0;
for (i = 0; i < ARRNELEM(add); i++) {
CPTRGM( ((char*)&tmp), ptr+i );
HASH(sbase, tmp);
}
}
return 0;
}
Datum
gtrgm_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
int4 len = entryvec->n;
int *size = (int *) PG_GETARG_POINTER(1);
BITVEC base;
int4 i;
int4 flag = 0;
TRGM *result;
MemSet((void *) base, 0, sizeof(BITVEC));
for (i = 0; i < len; i++)
{
if (unionkey(base, GETENTRY(entryvec, i)))
{
flag = ALLISTRUE;
break;
}
}
flag |= SIGNKEY;
len = CALCGTSIZE(flag, 0);
result = (TRGM *) palloc(len);
*size = result->len = len;
result->flag = flag;
if (!ISALLTRUE(result))
memcpy((void *) GETSIGN(result), (void *) base, sizeof(BITVEC));
PG_RETURN_POINTER(result);
}
Datum
gtrgm_same(PG_FUNCTION_ARGS)
{
TRGM *a = (TRGM *) PG_GETARG_POINTER(0);
TRGM *b = (TRGM *) 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
{
trgm *ptra = GETARR(a),
*ptrb = GETARR(b);
int4 i;
*result = true;
for (i = 0; i < lena; i++)
if (CMPTRGM(ptra+i, ptrb+i))
{
*result = false;
break;
}
}
}
PG_RETURN_POINTER(result);
}
static int4
sizebitvec(BITVECP sign)
{
int4 size = 0,
i;
LOOPBYTE(
size += SUMBIT(*(char *) sign);
sign = (BITVECP) (((char *) sign) + 1);
);
return size;
}
static int
hemdistsign(BITVECP a, BITVECP b) {
int i,dist=0;
LOOPBIT(
if ( GETBIT(a,i) != GETBIT(b,i) )
dist++;
);
return dist;
}
static int
hemdist(TRGM *a, TRGM *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
gtrgm_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);
TRGM *origval = (TRGM *) DatumGetPointer(origentry->key);
TRGM *newval = (TRGM *) 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, TRGM * 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
gtrgm_picksplit(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
OffsetNumber maxoff = entryvec->n - 2;
GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
OffsetNumber k,
j;
TRGM *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;
BITVECP ptr;
int i;
CACHESIGN *cache;
SPLITCOST *costvector;
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 = (TRGM *) palloc(CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
datum_l->len = CALCGTSIZE(SIGNKEY | ALLISTRUE, 0);
datum_l->flag = SIGNKEY | ALLISTRUE;
} else {
datum_l = (TRGM *) palloc(CALCGTSIZE(SIGNKEY, 0));
datum_l->len = 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 = (TRGM *) palloc(CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
datum_r->len = CALCGTSIZE(SIGNKEY | ALLISTRUE, 0);
datum_r->flag = SIGNKEY | ALLISTRUE;
} else {
datum_r = (TRGM *) palloc(CALCGTSIZE(SIGNKEY, 0));
datum_r->len = 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;
pfree(costvector);
pfree(cache);
v->spl_ldatum = PointerGetDatum(datum_l);
v->spl_rdatum = PointerGetDatum(datum_r);
PG_RETURN_POINTER(v);
}