/* Enlarge b_union to contain b_new. If b_new contains more
dimensions than b_union, expand b_union to contain those dimensions. */
static void gidx_merge(GIDX **b_union, GIDX *b_new)
{
int i, dims_union, dims_new;
Assert(b_union);
Assert(*b_union);
Assert(b_new);
dims_union = GIDX_NDIMS(*b_union);
dims_new = GIDX_NDIMS(b_new);
POSTGIS_DEBUGF(4, "merging gidx (%s) into gidx (%s)", gidx_to_string(b_new), gidx_to_string(*b_union));
if ( dims_new > dims_union )
{
POSTGIS_DEBUGF(5, "reallocating b_union from %d dims to %d dims", dims_union, dims_new);
*b_union = (GIDX*)repalloc(*b_union, GIDX_SIZE(dims_new));
SET_VARSIZE(*b_union, VARSIZE(b_new));
dims_union = dims_new;
}
for ( i = 0; i < dims_new; i++ )
{
/* Adjust minimums */
GIDX_SET_MIN(*b_union, i, Min(GIDX_GET_MIN(*b_union,i),GIDX_GET_MIN(b_new,i)));
/* Adjust maximums */
GIDX_SET_MAX(*b_union, i, Max(GIDX_GET_MAX(*b_union,i),GIDX_GET_MAX(b_new,i)));
}
POSTGIS_DEBUGF(5, "merge complete (%s)", gidx_to_string(*b_union));
return;
}
/* Calculate the volume of the intersection of the boxes. */
static float gidx_inter_volume(GIDX *a, GIDX *b)
{
int i;
float result;
POSTGIS_DEBUG(5,"entered function");
if ( a == NULL || b == NULL )
{
elog(ERROR, "gidx_inter_volume received a null argument");
return 0.0;
}
/* Ensure 'a' has the most dimensions. */
gidx_dimensionality_check(&a, &b);
/* Initialize with minimal length of first dimension. */
result = Min(GIDX_GET_MAX(a,0),GIDX_GET_MAX(b,0)) - Max(GIDX_GET_MIN(a,0),GIDX_GET_MIN(b,0));
/* If they are disjoint (max < min) then return zero. */
if ( result < 0.0 ) return 0.0;
/* Continue for remaining dimensions. */
for ( i = 1; i < GIDX_NDIMS(b); i++ )
{
float width = Min(GIDX_GET_MAX(a,i),GIDX_GET_MAX(b,i)) - Max(GIDX_GET_MIN(a,i),GIDX_GET_MIN(b,i));
if ( width < 0.0 ) return 0.0;
/* Multiply by minimal length of remaining dimensions. */
result *= width;
}
POSTGIS_DEBUGF(5, "volume( %s intersection %s ) = %.12g", gidx_to_string(a), gidx_to_string(b), result);
return result;
}
Datum geography_gist_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
int *sizep = (int *) PG_GETARG_POINTER(1); /* Size of the return value */
int numranges, i;
GIDX *box_cur, *box_union;
POSTGIS_DEBUG(4, "[GIST] 'union' function called");
numranges = entryvec->n;
box_cur = (GIDX*) DatumGetPointer(entryvec->vector[0].key);
box_union = gidx_copy(box_cur);
for ( i = 1; i < numranges; i++ )
{
box_cur = (GIDX*) DatumGetPointer(entryvec->vector[i].key);
gidx_merge(&box_union, box_cur);
}
*sizep = VARSIZE(box_union);
POSTGIS_DEBUGF(4, "[GIST] union called, numranges(%i), pageunion %s", numranges, gidx_to_string(box_union));
PG_RETURN_POINTER(box_union);
}
/*
** Peak into a geography to find the bounding box. If the
** box is there, copy it out and return it. If not, calculate the box from the
** full geography and return the box based on that. If no box is available,
** return G_FAILURE, otherwise G_SUCCESS.
*/
int geography_gidx(GSERIALIZED *g, GIDX *gidx)
{
int result = G_SUCCESS;
POSTGIS_DEBUG(4, "entered function");
POSTGIS_DEBUGF(4, "got flags %d", g->flags);
if ( FLAGS_GET_BBOX(g->flags) && FLAGS_GET_GEODETIC(g->flags) )
{
const size_t size = 2 * 3 * sizeof(float);
POSTGIS_DEBUG(4, "copying box out of serialization");
memcpy(gidx->c, g->data, size);
SET_VARSIZE(gidx, VARHDRSZ + size);
}
else
{
GBOX gbox;
POSTGIS_DEBUG(4, "calculating new box from scratch");
if ( gserialized_calculate_gbox_geocentric_p(g, &gbox) == G_FAILURE )
{
POSTGIS_DEBUG(4, "calculated null bbox, returning null");
return G_FAILURE;
}
result = gidx_from_gbox_p(gbox, gidx);
}
if ( result == G_SUCCESS )
{
POSTGIS_DEBUGF(4, "got gidx %s", gidx_to_string(gidx));
}
return result;
}
/**
* Peak into a #GSERIALIZED datum to find the bounding box. If the
* box is there, copy it out and return it. If not, calculate the box from the
* full object and return the box based on that. If no box is available,
* return #LW_FAILURE, otherwise #LW_SUCCESS.
*/
int
gserialized_datum_get_gidx_p(Datum gsdatum, GIDX *gidx)
{
GSERIALIZED *gpart;
int result = LW_SUCCESS;
POSTGIS_DEBUG(4, "entered function");
/*
** The most info we need is the 8 bytes of serialized header plus the 32 bytes
** of floats necessary to hold the 8 floats of the largest XYZM index
** bounding box, so 40 bytes.
*/
gpart = (GSERIALIZED*)PG_DETOAST_DATUM_SLICE(gsdatum, 0, 40);
POSTGIS_DEBUGF(4, "got flags %d", gpart->flags);
/* Do we even have a serialized bounding box? */
if ( FLAGS_GET_BBOX(gpart->flags) )
{
/* Yes! Copy it out into the GIDX! */
size_t size = gbox_serialized_size(gpart->flags);
POSTGIS_DEBUG(4, "copying box out of serialization");
memcpy(gidx->c, gpart->data, size);
/* if M is present but Z is not, pad Z and shift M */
if ( FLAGS_GET_M(gpart->flags) && ! FLAGS_GET_Z(gpart->flags) )
{
size += 2 * sizeof(float);
GIDX_SET_MIN(gidx,3,GIDX_GET_MIN(gidx,2));
GIDX_SET_MAX(gidx,3,GIDX_GET_MAX(gidx,2));
GIDX_SET_MIN(gidx,2,-1*FLT_MAX);
GIDX_SET_MAX(gidx,2,FLT_MAX);
}
SET_VARSIZE(gidx, VARHDRSZ + size);
result = LW_SUCCESS;
}
else
{
/* No, we need to calculate it from the full object. */
GSERIALIZED *g = (GSERIALIZED*)PG_DETOAST_DATUM(gsdatum);
LWGEOM *lwgeom = lwgeom_from_gserialized(g);
GBOX gbox;
if ( lwgeom_calculate_gbox(lwgeom, &gbox) == LW_FAILURE )
{
POSTGIS_DEBUG(4, "could not calculate bbox, returning failure");
lwgeom_free(lwgeom);
return LW_FAILURE;
}
lwgeom_free(lwgeom);
result = gidx_from_gbox_p(gbox, gidx);
}
if ( result == LW_SUCCESS )
{
POSTGIS_DEBUGF(4, "got gidx %s", gidx_to_string(gidx));
}
return result;
}
/* Calculate the volume of the union of the boxes. Avoids creating an intermediate box. */
static float gidx_union_volume(GIDX *a, GIDX *b)
{
float result;
int i;
int ndims_a, ndims_b;
POSTGIS_DEBUG(5,"entered function");
if ( a == NULL && b == NULL )
{
elog(ERROR, "gidx_union_volume received two null arguments");
return 0.0;
}
if ( a == NULL )
return gidx_volume(b);
if ( b == NULL )
return gidx_volume(a);
/* Ensure 'a' has the most dimensions. */
gidx_dimensionality_check(&a, &b);
ndims_a = GIDX_NDIMS(a);
ndims_b = GIDX_NDIMS(b);
/* Initialize with maximal length of first dimension. */
result = Max(GIDX_GET_MAX(a,0),GIDX_GET_MAX(b,0)) - Min(GIDX_GET_MIN(a,0),GIDX_GET_MIN(b,0));
/* Multiply by maximal length of remaining dimensions. */
for ( i = 1; i < ndims_b; i++ )
{
result *= (Max(GIDX_GET_MAX(a,i),GIDX_GET_MAX(b,i)) - Min(GIDX_GET_MIN(a,i),GIDX_GET_MIN(b,i)));
}
/* Add in dimensions of higher dimensional box. */
for ( i = ndims_b; i < ndims_a; i++ )
{
result *= (GIDX_GET_MAX(a,i) - GIDX_GET_MIN(a,i));
}
POSTGIS_DEBUGF(5, "volume( %s union %s ) = %.12g", gidx_to_string(a), gidx_to_string(b), result);
return result;
}
/* Calculate the volume (in n-d units) of the GIDX */
static float gidx_volume(GIDX *a)
{
float result;
int i;
if ( a == NULL )
{
/* elog(ERROR, "gidx_volume received a null argument"); */
return 0.0;
}
result = GIDX_GET_MAX(a,0) - GIDX_GET_MIN(a,0);
for ( i = 1; i < GIDX_NDIMS(a); i++ )
result *= (GIDX_GET_MAX(a,i) - GIDX_GET_MIN(a,i));
POSTGIS_DEBUGF(5, "calculated volume of %s as %.12g", gidx_to_string(a), result);
return result;
}
/* Ensure all minimums are below maximums. */
static inline void gidx_validate(GIDX *b)
{
int i;
Assert(b);
POSTGIS_DEBUGF(5,"validating gidx (%s)", gidx_to_string(b));
for ( i = 0; i < GIDX_NDIMS(b); i++ )
{
if ( GIDX_GET_MIN(b,i) > GIDX_GET_MAX(b,i) )
{
float tmp;
tmp = GIDX_GET_MIN(b,i);
GIDX_SET_MIN(b,i,GIDX_GET_MAX(b,i));
GIDX_SET_MAX(b,i,tmp);
}
}
return;
}
/* Convert a double-based GBOX into a float-based GIDX,
ensuring the float box is larger than the double box */
static int gidx_from_gbox_p(GBOX box, GIDX *a)
{
int ndims;
ndims = (FLAGS_GET_GEODETIC(box.flags) ? 3 : FLAGS_NDIMS(box.flags));
SET_VARSIZE(a, VARHDRSZ + ndims * 2 * sizeof(float));
GIDX_SET_MIN(a,0,nextDown_f(box.xmin));
GIDX_SET_MAX(a,0,nextUp_f(box.xmax));
GIDX_SET_MIN(a,1,nextDown_f(box.ymin));
GIDX_SET_MAX(a,1,nextUp_f(box.ymax));
/* Geodetic indexes are always 3d, geocentric x/y/z */
if ( FLAGS_GET_GEODETIC(box.flags) )
{
GIDX_SET_MIN(a,2,nextDown_f(box.zmin));
GIDX_SET_MAX(a,2,nextUp_f(box.zmax));
}
else
{
/* Cartesian with Z implies Z is third dimension */
if ( FLAGS_GET_Z(box.flags) )
{
GIDX_SET_MIN(a,2,nextDown_f(box.zmin));
GIDX_SET_MAX(a,2,nextUp_f(box.zmax));
if ( FLAGS_GET_M(box.flags) )
{
GIDX_SET_MIN(a,3,nextDown_f(box.mmin));
GIDX_SET_MAX(a,3,nextUp_f(box.mmax));
}
}
/* Unless there's no Z, in which case M is third dimension */
else if ( FLAGS_GET_M(box.flags) )
{
GIDX_SET_MIN(a,2,nextDown_f(box.mmin));
GIDX_SET_MAX(a,2,nextUp_f(box.mmax));
}
}
POSTGIS_DEBUGF(5, "converted %s to %s", gbox_to_string(&box), gidx_to_string(a));
return G_SUCCESS;
}
/* Convert a double-based GBOX into a float-based GIDX,
ensuring the float box is larger than the double box */
static int gidx_from_gbox_p(GBOX box, GIDX *a)
{
int ndims;
ndims = FLAGS_NDIMS_GIDX(box.flags);
SET_VARSIZE(a, VARHDRSZ + ndims * 2 * sizeof(float));
GIDX_SET_MIN(a,0,next_float_down(box.xmin));
GIDX_SET_MAX(a,0,next_float_up(box.xmax));
GIDX_SET_MIN(a,1,next_float_down(box.ymin));
GIDX_SET_MAX(a,1,next_float_up(box.ymax));
/* Geodetic indexes are always 3d, geocentric x/y/z */
if ( FLAGS_GET_GEODETIC(box.flags) )
{
GIDX_SET_MIN(a,2,next_float_down(box.zmin));
GIDX_SET_MAX(a,2,next_float_up(box.zmax));
}
else
{
/* Cartesian with Z implies Z is third dimension */
if ( FLAGS_GET_Z(box.flags) )
{
GIDX_SET_MIN(a,2,next_float_down(box.zmin));
GIDX_SET_MAX(a,2,next_float_up(box.zmax));
}
/* M is always fourth dimension, we pad if needed */
if ( FLAGS_GET_M(box.flags) )
{
if ( ! FLAGS_GET_Z(box.flags) )
{
GIDX_SET_MIN(a,2,-1*FLT_MAX);
GIDX_SET_MAX(a,2,FLT_MAX);
}
GIDX_SET_MIN(a,3,next_float_down(box.mmin));
GIDX_SET_MAX(a,3,next_float_up(box.mmax));
}
}
POSTGIS_DEBUGF(5, "converted %s to %s", gbox_to_string(&box), gidx_to_string(a));
return LW_SUCCESS;
}
/*
** Peak into a geography (gserialized) datum to find the bounding box. If the
** box is there, copy it out and return it. If not, calculate the box from the
** full geography and return the box based on that. If no box is available,
** return G_FAILURE, otherwise G_SUCCESS.
*/
int geography_datum_gidx(Datum geography_datum, GIDX *gidx)
{
GSERIALIZED *gpart;
int result = G_SUCCESS;
POSTGIS_DEBUG(4, "entered function");
/*
** The most info we need is the 8 bytes of serialized header plus the 24 bytes
** of floats necessary to hold the 6 floats of the geocentric index
** bounding box, so 32 bytes.
*/
gpart = (GSERIALIZED*)PG_DETOAST_DATUM_SLICE(geography_datum, 0, 32);
POSTGIS_DEBUGF(4, "got flags %d", gpart->flags);
if ( FLAGS_GET_BBOX(gpart->flags) && FLAGS_GET_GEODETIC(gpart->flags) )
{
const size_t size = 2 * 3 * sizeof(float);
POSTGIS_DEBUG(4, "copying box out of serialization");
memcpy(gidx->c, gpart->data, size);
SET_VARSIZE(gidx, VARHDRSZ + size);
}
else
{
GSERIALIZED *g = (GSERIALIZED*)PG_DETOAST_DATUM(geography_datum);
GBOX gbox;
POSTGIS_DEBUG(4, "calculating new box from scratch");
if ( gserialized_calculate_gbox_geocentric_p(g, &gbox) == G_FAILURE )
{
POSTGIS_DEBUG(4, "calculated null bbox, returning null");
return G_FAILURE;
}
result = gidx_from_gbox_p(gbox, gidx);
}
if ( result == G_SUCCESS )
{
POSTGIS_DEBUGF(4, "got gidx %s", gidx_to_string(gidx));
}
return result;
}
/*
** Peak into a geography to find the bounding box. If the
** box is there, copy it out and return it. If not, calculate the box from the
** full geography and return the box based on that. If no box is available,
** return LW_FAILURE, otherwise LW_SUCCESS.
*/
int gserialized_get_gidx_p(GSERIALIZED *g, GIDX *gidx)
{
int result = LW_SUCCESS;
POSTGIS_DEBUG(4, "entered function");
POSTGIS_DEBUGF(4, "got flags %d", g->flags);
if ( FLAGS_GET_BBOX(g->flags) )
{
int ndims = FLAGS_NDIMS_GIDX(g->flags);
const size_t size = 2 * ndims * sizeof(float);
POSTGIS_DEBUG(4, "copying box out of serialization");
memcpy(gidx->c, g->data, size);
SET_VARSIZE(gidx, VARHDRSZ + size);
}
else
{
/* No, we need to calculate it from the full object. */
LWGEOM *lwgeom = lwgeom_from_gserialized(g);
GBOX gbox;
if ( lwgeom_calculate_gbox(lwgeom, &gbox) == LW_FAILURE )
{
POSTGIS_DEBUG(4, "could not calculate bbox, returning failure");
lwgeom_free(lwgeom);
return LW_FAILURE;
}
lwgeom_free(lwgeom);
result = gidx_from_gbox_p(gbox, gidx);
}
if ( result == LW_SUCCESS )
{
POSTGIS_DEBUGF(4, "got gidx %s", gidx_to_string(gidx));
}
return result;
}
Datum geography_gist_compress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry_in = (GISTENTRY*)PG_GETARG_POINTER(0);
GISTENTRY *entry_out = NULL;
char gidxmem[GIDX_MAX_SIZE];
GIDX *bbox_out = (GIDX*)gidxmem;
int result = G_SUCCESS;
int i;
POSTGIS_DEBUG(4, "[GIST] 'compress' function called");
/*
** Not a leaf key? There's nothing to do.
** Return the input unchanged.
*/
if ( ! entry_in->leafkey )
{
POSTGIS_DEBUG(4, "[GIST] non-leafkey entry, returning input unaltered");
PG_RETURN_POINTER(entry_in);
}
POSTGIS_DEBUG(4, "[GIST] processing leafkey input");
entry_out = palloc(sizeof(GISTENTRY));
/*
** Null key? Make a copy of the input entry and
** return.
*/
if ( DatumGetPointer(entry_in->key) == NULL )
{
POSTGIS_DEBUG(4, "[GIST] leafkey is null");
gistentryinit(*entry_out, (Datum) 0, entry_in->rel,
entry_in->page, entry_in->offset, FALSE);
POSTGIS_DEBUG(4, "[GIST] returning copy of input");
PG_RETURN_POINTER(entry_out);
}
/* Extract our index key from the GiST entry. */
result = geography_datum_gidx(entry_in->key, bbox_out);
/* Is the bounding box valid (non-empty, non-infinite)? If not, return input uncompressed. */
if ( result == G_FAILURE )
{
POSTGIS_DEBUG(4, "[GIST] empty geometry!");
PG_RETURN_POINTER(entry_in);
}
POSTGIS_DEBUGF(4, "[GIST] got entry_in->key: %s", gidx_to_string(bbox_out));
/* Check all the dimensions for finite values */
for ( i = 0; i < GIDX_NDIMS(bbox_out); i++ )
{
if ( ! finite(GIDX_GET_MAX(bbox_out, i)) || ! finite(GIDX_GET_MIN(bbox_out, i)) )
{
POSTGIS_DEBUG(4, "[GIST] infinite geometry!");
PG_RETURN_POINTER(entry_in);
}
}
/* Enure bounding box has minimums below maximums. */
gidx_validate(bbox_out);
/* Prepare GISTENTRY for return. */
gistentryinit(*entry_out, PointerGetDatum(gidx_copy(bbox_out)),
entry_in->rel, entry_in->page, entry_in->offset, FALSE);
/* Return GISTENTRY. */
POSTGIS_DEBUG(4, "[GIST] 'compress' function complete");
PG_RETURN_POINTER(entry_out);
}
Datum geography_gist_picksplit(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector*) PG_GETARG_POINTER(0);
GIST_SPLITVEC *v = (GIST_SPLITVEC*) PG_GETARG_POINTER(1);
OffsetNumber i;
/* One union box for each half of the space. */
GIDX **box_union;
/* One offset number list for each half of the space. */
OffsetNumber **list;
/* One position index for each half of the space. */
int *pos;
GIDX *box_pageunion;
GIDX *box_current;
int direction = -1;
bool all_entries_equal = true;
OffsetNumber max_offset;
int nbytes, ndims_pageunion, d;
int posmax = -1;
POSTGIS_DEBUG(4, "[GIST] 'picksplit' function called");
/*
** First calculate the bounding box and maximum number of dimensions in this page.
*/
max_offset = entryvec->n - 1;
box_current = (GIDX*) DatumGetPointer(entryvec->vector[FirstOffsetNumber].key);
box_pageunion = gidx_copy(box_current);
/* Calculate the containing box (box_pageunion) for the whole page we are going to split. */
for ( i = OffsetNumberNext(FirstOffsetNumber); i <= max_offset; i = OffsetNumberNext(i) )
{
box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);
if ( all_entries_equal == true && ! gidx_equals (box_pageunion, box_current) )
all_entries_equal = false;
gidx_merge( &box_pageunion, box_current );
}
POSTGIS_DEBUGF(3, "[GIST] box_pageunion: %s", gidx_to_string(box_pageunion));
/* Every box in the page is the same! So, we split and just put half the boxes in each child. */
if ( all_entries_equal )
{
POSTGIS_DEBUG(4, "[GIST] picksplit finds all entries equal!");
geography_gist_picksplit_fallback(entryvec, v);
PG_RETURN_POINTER(v);
}
/* Initialize memory structures. */
nbytes = (max_offset + 2) * sizeof(OffsetNumber);
ndims_pageunion = GIDX_NDIMS(box_pageunion);
POSTGIS_DEBUGF(4, "[GIST] ndims_pageunion == %d", ndims_pageunion);
pos = palloc(2*ndims_pageunion * sizeof(int));
list = palloc(2*ndims_pageunion * sizeof(OffsetNumber*));
box_union = palloc(2*ndims_pageunion * sizeof(GIDX*));
for ( d = 0; d < ndims_pageunion; d++ )
{
list[BELOW(d)] = (OffsetNumber*) palloc(nbytes);
list[ABOVE(d)] = (OffsetNumber*) palloc(nbytes);
box_union[BELOW(d)] = gidx_new(ndims_pageunion);
box_union[ABOVE(d)] = gidx_new(ndims_pageunion);
pos[BELOW(d)] = 0;
pos[ABOVE(d)] = 0;
}
/*
** Assign each entry in the node to the volume partitions it belongs to,
** such as "above the x/y plane, left of the y/z plane, below the x/z plane".
** Each entry thereby ends up in three of the six partitions.
*/
POSTGIS_DEBUG(4, "[GIST] 'picksplit' calculating best split axis");
for ( i = FirstOffsetNumber; i <= max_offset; i = OffsetNumberNext(i) )
{
box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);
for ( d = 0; d < ndims_pageunion; d++ )
{
if ( GIDX_GET_MIN(box_current,d)-GIDX_GET_MIN(box_pageunion,d) < GIDX_GET_MAX(box_pageunion,d)-GIDX_GET_MAX(box_current,d) )
{
geography_gist_picksplit_addlist(list[BELOW(d)], &(box_union[BELOW(d)]), box_current, &(pos[BELOW(d)]), i);
}
else
{
geography_gist_picksplit_addlist(list[ABOVE(d)], &(box_union[ABOVE(d)]), box_current, &(pos[ABOVE(d)]), i);
}
}
}
/*
** "Bad disposition", too many entries fell into one octant of the space, so no matter which
** plane we choose to split on, we're going to end up with a mostly full node. Where the
** data is pretty homogeneous (lots of duplicates) entries that are equidistant from the
** sides of the page union box can occasionally all end up in one place, leading
** to this condition.
*/
if ( geography_gist_picksplit_badratios(pos,ndims_pageunion) == TRUE )
{
/*
** Instead we split on center points and see if we do better.
** First calculate the average center point for each axis.
*/
double *avgCenter = palloc(ndims_pageunion * sizeof(double));
for ( d = 0; d < ndims_pageunion; d++ )
{
avgCenter[d] = 0.0;
}
POSTGIS_DEBUG(4, "[GIST] picksplit can't find good split axis, trying center point method");
for ( i = FirstOffsetNumber; i <= max_offset; i = OffsetNumberNext(i) )
{
box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);
for ( d = 0; d < ndims_pageunion; d++ )
{
avgCenter[d] += (GIDX_GET_MAX(box_current,d) + GIDX_GET_MIN(box_current,d)) / 2.0;
}
}
for ( d = 0; d < ndims_pageunion; d++ )
{
avgCenter[d] /= max_offset;
pos[BELOW(d)] = pos[ABOVE(d)] = 0; /* Re-initialize our counters. */
POSTGIS_DEBUGF(4, "[GIST] picksplit average center point[%d] = %.12g", d, avgCenter[d]);
}
/* For each of our entries... */
for ( i = FirstOffsetNumber; i <= max_offset; i = OffsetNumberNext(i) )
{
double center;
box_current = (GIDX*) DatumGetPointer(entryvec->vector[i].key);
for ( d = 0; d < ndims_pageunion; d++ )
{
center = (GIDX_GET_MIN(box_current,d)+GIDX_GET_MAX(box_current,d))/2.0;
if ( center < avgCenter[d] )
geography_gist_picksplit_addlist(list[BELOW(d)], &(box_union[BELOW(d)]), box_current, &(pos[BELOW(d)]), i);
else if ( FPeq(center, avgCenter[d]) )
if ( pos[BELOW(d)] > pos[ABOVE(d)] )
geography_gist_picksplit_addlist(list[ABOVE(d)], &(box_union[ABOVE(d)]), box_current, &(pos[ABOVE(d)]), i);
else
geography_gist_picksplit_addlist(list[BELOW(d)], &(box_union[BELOW(d)]), box_current, &(pos[BELOW(d)]), i);
else
geography_gist_picksplit_addlist(list[ABOVE(d)], &(box_union[ABOVE(d)]), box_current, &(pos[ABOVE(d)]), i);
}
}
/* Do we have a good disposition now? If not, screw it, just cut the node in half. */
if ( geography_gist_picksplit_badratios(pos,ndims_pageunion) == TRUE )
{
POSTGIS_DEBUG(4, "[GIST] picksplit still cannot find a good split! just cutting the node in half");
geography_gist_picksplit_fallback(entryvec, v);
PG_RETURN_POINTER(v);
}
}
/*
** Now, what splitting plane gives us the most even ratio of
** entries in our child pages? Since each split region has been apportioned entries
** against the same number of total entries, the axis that has the smallest maximum
** number of entries in its regions is the most evenly distributed.
** TODO: what if the distributions are equal in two or more axes?
*/
for ( d = 0; d < ndims_pageunion; d++ )
{
int posd = Max(pos[ABOVE(d)],pos[BELOW(d)]);
if ( posd > posmax )
{
direction = d;
posmax = posd;
}
}
if ( direction == -1 || posmax == -1 )
{
/* ERROR OUT HERE */
elog(ERROR, "Error in building split, unable to determine split direction.");
}
POSTGIS_DEBUGF(3, "[GIST] 'picksplit' splitting on axis %d", direction);
geography_gist_picksplit_constructsplit(v, list[BELOW(direction)],
pos[BELOW(direction)],
&(box_union[BELOW(direction)]),
list[ABOVE(direction)],
pos[ABOVE(direction)],
&(box_union[ABOVE(direction)]) );
POSTGIS_DEBUGF(4, "[GIST] spl_ldatum: %s", gidx_to_string((GIDX*)v->spl_ldatum));
POSTGIS_DEBUGF(4, "[GIST] spl_rdatum: %s", gidx_to_string((GIDX*)v->spl_rdatum));
POSTGIS_DEBUGF(4, "[GIST] axis %d: parent range (%.12g, %.12g) left range (%.12g, %.12g), right range (%.12g, %.12g)",
direction,
GIDX_GET_MIN(box_pageunion, direction), GIDX_GET_MAX(box_pageunion, direction),
GIDX_GET_MIN((GIDX*)v->spl_ldatum, direction), GIDX_GET_MAX((GIDX*)v->spl_ldatum, direction),
GIDX_GET_MIN((GIDX*)v->spl_rdatum, direction), GIDX_GET_MAX((GIDX*)v->spl_rdatum, direction) );
PG_RETURN_POINTER(v);
}
