/*
** The GiST Union method for boxes
** returns the minimal bounding box that encloses all the entries in entryvec
*/
Datum
g_cube_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
int *sizep = (int *) PG_GETARG_POINTER(1);
NDBOX *out = (NDBOX *) NULL;
NDBOX *tmp;
int i;
/*
* fprintf(stderr, "union\n");
*/
tmp = DatumGetNDBOX(entryvec->vector[0].key);
/*
* sizep = sizeof(NDBOX); -- NDBOX has variable size
*/
*sizep = VARSIZE(tmp);
for (i = 1; i < entryvec->n; i++)
{
out = g_cube_binary_union(tmp,
DatumGetNDBOX(entryvec->vector[i].key),
sizep);
tmp = out;
}
PG_RETURN_POINTER(out);
}
/*
** The GiST Consistent method for boxes
** Should return false if for all data items x below entry,
** the predicate x op query == FALSE, where op is the oper
** corresponding to strategy in the pg_amop table.
*/
Datum
g_cube_consistent(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
NDBOX *query = PG_GETARG_NDBOX(1);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
/* Oid subtype = PG_GETARG_OID(3); */
bool *recheck = (bool *) PG_GETARG_POINTER(4);
bool res;
/* All cases served by this function are exact */
*recheck = false;
/*
* if entry is not leaf, use g_cube_internal_consistent, else use
* g_cube_leaf_consistent
*/
if (GIST_LEAF(entry))
res = g_cube_leaf_consistent(DatumGetNDBOX(entry->key),
query, strategy);
else
res = g_cube_internal_consistent(DatumGetNDBOX(entry->key),
query, strategy);
PG_FREE_IF_COPY(query, 1);
PG_RETURN_BOOL(res);
}
Datum
g_cube_decompress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
NDBOX *key = DatumGetNDBOX(PG_DETOAST_DATUM(entry->key));
if (key != DatumGetNDBOX(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);
}
/*
** The GiST Penalty method for boxes
** As in the R-tree paper, we use change in area as our penalty metric
*/
Datum
g_cube_penalty(PG_FUNCTION_ARGS)
{
GISTENTRY *origentry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *newentry = (GISTENTRY *) PG_GETARG_POINTER(1);
float *result = (float *) PG_GETARG_POINTER(2);
NDBOX *ud;
double tmp1,
tmp2;
ud = cube_union_v0(DatumGetNDBOX(origentry->key),
DatumGetNDBOX(newentry->key));
rt_cube_size(ud, &tmp1);
rt_cube_size(DatumGetNDBOX(origentry->key), &tmp2);
*result = (float) (tmp1 - tmp2);
/*
* fprintf(stderr, "penalty\n"); fprintf(stderr, "\t%g\n", *result);
*/
PG_RETURN_FLOAT8(*result);
}
/*
** The GiST Consistent method for boxes
** Should return false if for all data items x below entry,
** the predicate x op query == FALSE, where op is the oper
** corresponding to strategy in the pg_amop table.
*/
Datum
g_cube_consistent(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
NDBOX *query = PG_GETARG_NDBOX(1);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
bool res;
/*
* if entry is not leaf, use g_cube_internal_consistent, else use
* g_cube_leaf_consistent
*/
if (GIST_LEAF(entry))
res = g_cube_leaf_consistent( DatumGetNDBOX(entry->key),
query, strategy);
else
res = g_cube_internal_consistent( DatumGetNDBOX(entry->key),
query, strategy);
PG_FREE_IF_COPY(query,1);
PG_RETURN_BOOL(res);
}
/*
** The GiST PickSplit method for boxes
** We use Guttman's poly time split algorithm
*/
Datum
g_cube_picksplit(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
GIST_SPLITVEC *v = (GIST_SPLITVEC *) PG_GETARG_POINTER(1);
OffsetNumber i,
j;
NDBOX *datum_alpha,
*datum_beta;
NDBOX *datum_l,
*datum_r;
NDBOX *union_d,
*union_dl,
*union_dr;
NDBOX *inter_d;
bool firsttime;
double size_alpha,
size_beta,
size_union,
size_inter;
double size_waste,
waste;
double size_l,
size_r;
int nbytes;
OffsetNumber seed_1 = 1,
seed_2 = 2;
OffsetNumber *left,
*right;
OffsetNumber maxoff;
/*
* fprintf(stderr, "picksplit\n");
*/
maxoff = entryvec->n - 2;
nbytes = (maxoff + 2) * sizeof(OffsetNumber);
v->spl_left = (OffsetNumber *) palloc(nbytes);
v->spl_right = (OffsetNumber *) palloc(nbytes);
firsttime = true;
waste = 0.0;
for (i = FirstOffsetNumber; i < maxoff; i = OffsetNumberNext(i))
{
datum_alpha = DatumGetNDBOX(entryvec->vector[i].key);
for (j = OffsetNumberNext(i); j <= maxoff; j = OffsetNumberNext(j))
{
datum_beta = DatumGetNDBOX(entryvec->vector[j].key);
/* compute the wasted space by unioning these guys */
/* size_waste = size_union - size_inter; */
union_d = cube_union_v0(datum_alpha, datum_beta);
rt_cube_size(union_d, &size_union);
inter_d = DatumGetNDBOX(DirectFunctionCall2(cube_inter,
entryvec->vector[i].key, entryvec->vector[j].key));
rt_cube_size(inter_d, &size_inter);
size_waste = size_union - size_inter;
/*
* are these a more promising split than what we've already seen?
*/
if (size_waste > waste || firsttime)
{
waste = size_waste;
seed_1 = i;
seed_2 = j;
firsttime = false;
}
}
}
left = v->spl_left;
v->spl_nleft = 0;
right = v->spl_right;
v->spl_nright = 0;
datum_alpha = DatumGetNDBOX(entryvec->vector[seed_1].key);
datum_l = cube_union_v0(datum_alpha, datum_alpha);
rt_cube_size(datum_l, &size_l);
datum_beta = DatumGetNDBOX(entryvec->vector[seed_2].key);
datum_r = cube_union_v0(datum_beta, datum_beta);
rt_cube_size(datum_r, &size_r);
/*
* Now split up the regions between the two seeds. An important property
* of this split algorithm is that the split vector v has the indices of
* items to be split in order in its left and right vectors. We exploit
* this property by doing a merge in the code that actually splits the
* page.
*
* For efficiency, we also place the new index tuple in this loop. This is
* handled at the very end, when we have placed all the existing tuples
* and i == maxoff + 1.
*/
maxoff = OffsetNumberNext(maxoff);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
/*
* If we've already decided where to place this item, just put it on
* the right list. Otherwise, we need to figure out which page needs
* the least enlargement in order to store the item.
*/
if (i == seed_1)
{
*left++ = i;
v->spl_nleft++;
continue;
}
else if (i == seed_2)
{
*right++ = i;
v->spl_nright++;
continue;
}
/* okay, which page needs least enlargement? */
datum_alpha = DatumGetNDBOX(entryvec->vector[i].key);
union_dl = cube_union_v0(datum_l, datum_alpha);
union_dr = cube_union_v0(datum_r, datum_alpha);
rt_cube_size(union_dl, &size_alpha);
rt_cube_size(union_dr, &size_beta);
/* pick which page to add it to */
if (size_alpha - size_l < size_beta - size_r)
{
datum_l = union_dl;
size_l = size_alpha;
*left++ = i;
v->spl_nleft++;
}
else
{
datum_r = union_dr;
size_r = size_beta;
*right++ = i;
v->spl_nright++;
}
}
*left = *right = FirstOffsetNumber; /* sentinel value, see dosplit() */
v->spl_ldatum = PointerGetDatum(datum_l);
v->spl_rdatum = PointerGetDatum(datum_r);
PG_RETURN_POINTER(v);
}
