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Sourcecode: postgresql-8.4 version File versions

trgm_gist.c

/*
 * $PostgreSQL: pgsql/contrib/pg_trgm/trgm_gist.c,v 1.15 2008/07/11 11:56:48 teodor Exp $ 
 */
#include "trgm.h"

#include "access/gist.h"
#include "access/itup.h"
#include "access/tuptoaster.h"
#include "storage/bufpage.h"
#include "utils/array.h"
#include "utils/builtins.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))

/* 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
};


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     *val = DatumGetTextP(entry->key);

            res = generate_trgm(VARDATA(val), VARSIZE(val) - VARHDRSZ);
            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;
            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);
            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
gtrgm_decompress(PG_FUNCTION_ARGS)
{
      GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
      GISTENTRY  *retval;
      text     *key;

      key = DatumGetTextP(entry->key);

      if (key != (text *) DatumGetPointer(entry->key))
      {
            /* need to pass back the decompressed item */
            retval = palloc(sizeof(GISTENTRY));
            gistentryinit(*retval, PointerGetDatum(key),
                                entry->rel, entry->page, entry->offset, entry->leafkey);
            PG_RETURN_POINTER(retval);
      }
      else
      {
            /* we can return the entry as-is */
            PG_RETURN_POINTER(entry);
      }
}

Datum
gtrgm_consistent(PG_FUNCTION_ARGS)
{
      GISTENTRY  *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
      text     *query = PG_GETARG_TEXT_P(1);
      /* StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2); */
      /* Oid            subtype = PG_GETARG_OID(3); */
      bool     *recheck = (bool *) PG_GETARG_POINTER(4);
      TRGM     *key = (TRGM *) DatumGetPointer(entry->key);
      TRGM     *qtrg;
      bool        res = false;
      char        *cache  = (char*) fcinfo->flinfo->fn_extra;

      /* All cases served by this function are exact */
      *recheck = false;

      if ( cache == NULL || VARSIZE(cache) != VARSIZE(query) || memcmp( cache, query, VARSIZE(query) ) !=0  )
      {
            qtrg = generate_trgm(VARDATA(query), VARSIZE(query) - VARHDRSZ);    

            if (cache)
                  pfree(cache);

            fcinfo->flinfo->fn_extra = MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
                                          MAXALIGN(VARSIZE(query)) + VARSIZE(qtrg) );
            cache = (char*) fcinfo->flinfo->fn_extra;

            memcpy( cache, query, VARSIZE(query) );
            memcpy( cache + MAXALIGN(VARSIZE(query)), qtrg, VARSIZE(qtrg) );
      }

      qtrg = (TRGM*)( cache + MAXALIGN(VARSIZE(query)) );

      if (GIST_LEAF(entry))
      {                                         /* 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_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);
      SET_VARSIZE(result, len);
      result->flag = flag;
      if (!ISALLTRUE(result))
            memcpy((void *) GETSIGN(result), (void *) base, sizeof(BITVEC));
      *size = len;

      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 += 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(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));
            SET_VARSIZE(datum_l, CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
            datum_l->flag = SIGNKEY | ALLISTRUE;
      }
      else
      {
            datum_l = (TRGM *) 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 = (TRGM *) palloc(CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
            SET_VARSIZE(datum_r, CALCGTSIZE(SIGNKEY | ALLISTRUE, 0));
            datum_r->flag = SIGNKEY | ALLISTRUE;
      }
      else
      {
            datum_r = (TRGM *) 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);
}

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