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postgresql/src/backend/utils/adt/rangetypes_spgist.c

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/*-------------------------------------------------------------------------
*
* rangetypes_spgist.c
* implementation of quad tree over ranges mapped to 2d-points for SP-GiST.
*
* Quad tree is a data structure similar to a binary tree, but is adapted to
* 2d data. Each inner node of a quad tree contains a point (centroid) which
* divides the 2d-space into 4 quadrants. Each quadrant is associated with a
* child node.
*
* Ranges are mapped to 2d-points so that the lower bound is one dimension,
* and the upper bound is another. By convention, we visualize the lower bound
* to be the horizontal axis, and upper bound the vertical axis.
*
* One quirk with this mapping is the handling of empty ranges. An empty range
* doesn't have lower and upper bounds, so it cannot be mapped to 2d space in
* a straightforward way. To cope with that, the root node can have a 5th
* quadrant, which is reserved for empty ranges. Furthermore, there can be
* inner nodes in the tree with no centroid. They contain only two child nodes,
* one for empty ranges and another for non-empty ones. Such a node can appear
* as the root node, or in the tree under the 5th child of the root node (in
* which case it will only contain empty nodes).
*
* The SP-GiST picksplit function uses medians along both axes as the centroid.
* This implementation only uses the comparison function of the range element
* datatype, therefore it works for any range type.
*
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/adt/rangetypes_spgist.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/spgist.h"
#include "access/stratnum.h"
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/rangetypes.h"
static int16 getQuadrant(TypeCacheEntry *typcache, const RangeType *centroid,
const RangeType *tst);
static int bound_cmp(const void *a, const void *b, void *arg);
static int adjacent_inner_consistent(TypeCacheEntry *typcache,
const RangeBound *arg, const RangeBound *centroid,
const RangeBound *prev);
static int adjacent_cmp_bounds(TypeCacheEntry *typcache, const RangeBound *arg,
const RangeBound *centroid);
/*
* SP-GiST 'config' interface function.
*/
Datum
spg_range_quad_config(PG_FUNCTION_ARGS)
{
/* spgConfigIn *cfgin = (spgConfigIn *) PG_GETARG_POINTER(0); */
spgConfigOut *cfg = (spgConfigOut *) PG_GETARG_POINTER(1);
cfg->prefixType = ANYRANGEOID;
cfg->labelType = VOIDOID; /* we don't need node labels */
cfg->canReturnData = true;
cfg->longValuesOK = false;
PG_RETURN_VOID();
}
/*----------
* Determine which quadrant a 2d-mapped range falls into, relative to the
* centroid.
*
* Quadrants are numbered like this:
*
* 4 | 1
* ----+----
* 3 | 2
*
* Where the lower bound of range is the horizontal axis and upper bound the
* vertical axis.
*
* Ranges on one of the axes are taken to lie in the quadrant with higher value
* along perpendicular axis. That is, a value on the horizontal axis is taken
* to belong to quadrant 1 or 4, and a value on the vertical axis is taken to
* belong to quadrant 1 or 2. A range equal to centroid is taken to lie in
* quadrant 1.
*
* Empty ranges are taken to lie in the special quadrant 5.
*----------
*/
static int16
getQuadrant(TypeCacheEntry *typcache, const RangeType *centroid, const RangeType *tst)
{
RangeBound centroidLower,
centroidUpper;
bool centroidEmpty;
RangeBound lower,
upper;
bool empty;
range_deserialize(typcache, centroid, &centroidLower, &centroidUpper,
&centroidEmpty);
range_deserialize(typcache, tst, &lower, &upper, &empty);
if (empty)
return 5;
if (range_cmp_bounds(typcache, &lower, &centroidLower) >= 0)
{
if (range_cmp_bounds(typcache, &upper, &centroidUpper) >= 0)
return 1;
else
return 2;
}
else
{
if (range_cmp_bounds(typcache, &upper, &centroidUpper) >= 0)
return 4;
else
return 3;
}
}
/*
* Choose SP-GiST function: choose path for addition of new range.
*/
Datum
spg_range_quad_choose(PG_FUNCTION_ARGS)
{
spgChooseIn *in = (spgChooseIn *) PG_GETARG_POINTER(0);
spgChooseOut *out = (spgChooseOut *) PG_GETARG_POINTER(1);
RangeType *inRange = DatumGetRangeTypeP(in->datum),
*centroid;
int16 quadrant;
TypeCacheEntry *typcache;
if (in->allTheSame)
{
out->resultType = spgMatchNode;
/* nodeN will be set by core */
out->result.matchNode.levelAdd = 0;
out->result.matchNode.restDatum = RangeTypePGetDatum(inRange);
PG_RETURN_VOID();
}
typcache = range_get_typcache(fcinfo, RangeTypeGetOid(inRange));
/*
* A node with no centroid divides ranges purely on whether they're empty
* or not. All empty ranges go to child node 0, all non-empty ranges go to
* node 1.
*/
if (!in->hasPrefix)
{
out->resultType = spgMatchNode;
if (RangeIsEmpty(inRange))
out->result.matchNode.nodeN = 0;
else
out->result.matchNode.nodeN = 1;
out->result.matchNode.levelAdd = 1;
out->result.matchNode.restDatum = RangeTypePGetDatum(inRange);
PG_RETURN_VOID();
}
centroid = DatumGetRangeTypeP(in->prefixDatum);
quadrant = getQuadrant(typcache, centroid, inRange);
Assert(quadrant <= in->nNodes);
/* Select node matching to quadrant number */
out->resultType = spgMatchNode;
out->result.matchNode.nodeN = quadrant - 1;
out->result.matchNode.levelAdd = 1;
out->result.matchNode.restDatum = RangeTypePGetDatum(inRange);
PG_RETURN_VOID();
}
/*
* Bound comparison for sorting.
*/
static int
bound_cmp(const void *a, const void *b, void *arg)
{
RangeBound *ba = (RangeBound *) a;
RangeBound *bb = (RangeBound *) b;
TypeCacheEntry *typcache = (TypeCacheEntry *) arg;
return range_cmp_bounds(typcache, ba, bb);
}
/*
* Picksplit SP-GiST function: split ranges into nodes. Select "centroid"
* range and distribute ranges according to quadrants.
*/
Datum
spg_range_quad_picksplit(PG_FUNCTION_ARGS)
{
spgPickSplitIn *in = (spgPickSplitIn *) PG_GETARG_POINTER(0);
spgPickSplitOut *out = (spgPickSplitOut *) PG_GETARG_POINTER(1);
int i;
int j;
int nonEmptyCount;
RangeType *centroid;
bool empty;
TypeCacheEntry *typcache;
/* Use the median values of lower and upper bounds as the centroid range */
RangeBound *lowerBounds,
*upperBounds;
typcache = range_get_typcache(fcinfo,
RangeTypeGetOid(DatumGetRangeTypeP(in->datums[0])));
/* Allocate memory for bounds */
lowerBounds = palloc(sizeof(RangeBound) * in->nTuples);
upperBounds = palloc(sizeof(RangeBound) * in->nTuples);
j = 0;
/* Deserialize bounds of ranges, count non-empty ranges */
for (i = 0; i < in->nTuples; i++)
{
range_deserialize(typcache, DatumGetRangeTypeP(in->datums[i]),
&lowerBounds[j], &upperBounds[j], &empty);
if (!empty)
j++;
}
nonEmptyCount = j;
/*
* All the ranges are empty. The best we can do is to construct an inner
* node with no centroid, and put all ranges into node 0. If non-empty
* ranges are added later, they will be routed to node 1.
*/
if (nonEmptyCount == 0)
{
out->nNodes = 2;
out->hasPrefix = false;
/* Prefix is empty */
out->prefixDatum = PointerGetDatum(NULL);
out->nodeLabels = NULL;
out->mapTuplesToNodes = palloc(sizeof(int) * in->nTuples);
out->leafTupleDatums = palloc(sizeof(Datum) * in->nTuples);
/* Place all ranges into node 0 */
for (i = 0; i < in->nTuples; i++)
{
RangeType *range = DatumGetRangeTypeP(in->datums[i]);
out->leafTupleDatums[i] = RangeTypePGetDatum(range);
out->mapTuplesToNodes[i] = 0;
}
PG_RETURN_VOID();
}
/* Sort range bounds in order to find medians */
qsort_arg(lowerBounds, nonEmptyCount, sizeof(RangeBound),
bound_cmp, typcache);
qsort_arg(upperBounds, nonEmptyCount, sizeof(RangeBound),
bound_cmp, typcache);
/* Construct "centroid" range from medians of lower and upper bounds */
centroid = range_serialize(typcache, &lowerBounds[nonEmptyCount / 2],
&upperBounds[nonEmptyCount / 2], false);
out->hasPrefix = true;
out->prefixDatum = RangeTypePGetDatum(centroid);
/* Create node for empty ranges only if it is a root node */
out->nNodes = (in->level == 0) ? 5 : 4;
out->nodeLabels = NULL; /* we don't need node labels */
out->mapTuplesToNodes = palloc(sizeof(int) * in->nTuples);
out->leafTupleDatums = palloc(sizeof(Datum) * in->nTuples);
/*
* Assign ranges to corresponding nodes according to quadrants relative to
* "centroid" range.
*/
for (i = 0; i < in->nTuples; i++)
{
RangeType *range = DatumGetRangeTypeP(in->datums[i]);
int16 quadrant = getQuadrant(typcache, centroid, range);
out->leafTupleDatums[i] = RangeTypePGetDatum(range);
out->mapTuplesToNodes[i] = quadrant - 1;
}
PG_RETURN_VOID();
}
/*
* SP-GiST consistent function for inner nodes: check which nodes are
* consistent with given set of queries.
*/
Datum
spg_range_quad_inner_consistent(PG_FUNCTION_ARGS)
{
spgInnerConsistentIn *in = (spgInnerConsistentIn *) PG_GETARG_POINTER(0);
spgInnerConsistentOut *out = (spgInnerConsistentOut *) PG_GETARG_POINTER(1);
int which;
int i;
MemoryContext oldCtx;
/*
* For adjacent search we need also previous centroid (if any) to improve
* the precision of the consistent check. In this case needPrevious flag
* is set and centroid is passed into traversalValue.
*/
bool needPrevious = false;
if (in->allTheSame)
{
/* Report that all nodes should be visited */
out->nNodes = in->nNodes;
out->nodeNumbers = (int *) palloc(sizeof(int) * in->nNodes);
for (i = 0; i < in->nNodes; i++)
out->nodeNumbers[i] = i;
PG_RETURN_VOID();
}
if (!in->hasPrefix)
{
/*
* No centroid on this inner node. Such a node has two child nodes,
* the first for empty ranges, and the second for non-empty ones.
*/
Assert(in->nNodes == 2);
/*
* Nth bit of which variable means that (N - 1)th node should be
* visited. Initially all bits are set. Bits of nodes which should be
* skipped will be unset.
*/
which = (1 << 1) | (1 << 2);
for (i = 0; i < in->nkeys; i++)
{
StrategyNumber strategy = in->scankeys[i].sk_strategy;
bool empty;
/*
* The only strategy when second argument of operator is not range
* is RANGESTRAT_CONTAINS_ELEM.
*/
if (strategy != RANGESTRAT_CONTAINS_ELEM)
empty = RangeIsEmpty(DatumGetRangeTypeP(in->scankeys[i].sk_argument));
else
empty = false;
switch (strategy)
{
case RANGESTRAT_BEFORE:
case RANGESTRAT_OVERLEFT:
case RANGESTRAT_OVERLAPS:
case RANGESTRAT_OVERRIGHT:
case RANGESTRAT_AFTER:
case RANGESTRAT_ADJACENT:
/* These strategies return false if any argument is empty */
if (empty)
which = 0;
else
which &= (1 << 2);
break;
case RANGESTRAT_CONTAINS:
/*
* All ranges contain an empty range. Only non-empty
* ranges can contain a non-empty range.
*/
if (!empty)
which &= (1 << 2);
break;
case RANGESTRAT_CONTAINED_BY:
/*
* Only an empty range is contained by an empty range.
* Both empty and non-empty ranges can be contained by a
* non-empty range.
*/
if (empty)
which &= (1 << 1);
break;
case RANGESTRAT_CONTAINS_ELEM:
which &= (1 << 2);
break;
case RANGESTRAT_EQ:
if (empty)
which &= (1 << 1);
else
which &= (1 << 2);
break;
default:
elog(ERROR, "unrecognized range strategy: %d", strategy);
break;
}
if (which == 0)
break; /* no need to consider remaining conditions */
}
}
else
{
RangeBound centroidLower,
centroidUpper;
bool centroidEmpty;
TypeCacheEntry *typcache;
RangeType *centroid;
/* This node has a centroid. Fetch it. */
centroid = DatumGetRangeTypeP(in->prefixDatum);
typcache = range_get_typcache(fcinfo,
RangeTypeGetOid(DatumGetRangeTypeP(centroid)));
range_deserialize(typcache, centroid, &centroidLower, &centroidUpper,
&centroidEmpty);
Assert(in->nNodes == 4 || in->nNodes == 5);
/*
* Nth bit of which variable means that (N - 1)th node (Nth quadrant)
* should be visited. Initially all bits are set. Bits of nodes which
* can be skipped will be unset.
*/
which = (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4) | (1 << 5);
for (i = 0; i < in->nkeys; i++)
{
StrategyNumber strategy;
RangeBound lower,
upper;
bool empty;
RangeType *range = NULL;
RangeType *prevCentroid = NULL;
RangeBound prevLower,
prevUpper;
bool prevEmpty;
/* Restrictions on range bounds according to scan strategy */
RangeBound *minLower = NULL,
*maxLower = NULL,
*minUpper = NULL,
*maxUpper = NULL;
/* Are the restrictions on range bounds inclusive? */
bool inclusive = true;
bool strictEmpty = true;
int cmp,
which1,
which2;
strategy = in->scankeys[i].sk_strategy;
/*
* RANGESTRAT_CONTAINS_ELEM is just like RANGESTRAT_CONTAINS, but
* the argument is a single element. Expand the single element to
* a range containing only the element, and treat it like
* RANGESTRAT_CONTAINS.
*/
if (strategy == RANGESTRAT_CONTAINS_ELEM)
{
lower.inclusive = true;
lower.infinite = false;
lower.lower = true;
lower.val = in->scankeys[i].sk_argument;
upper.inclusive = true;
upper.infinite = false;
upper.lower = false;
upper.val = in->scankeys[i].sk_argument;
empty = false;
strategy = RANGESTRAT_CONTAINS;
}
else
{
range = DatumGetRangeTypeP(in->scankeys[i].sk_argument);
range_deserialize(typcache, range, &lower, &upper, &empty);
}
/*
* Most strategies are handled by forming a bounding box from the
* search key, defined by a minLower, maxLower, minUpper,
* maxUpper. Some modify 'which' directly, to specify exactly
* which quadrants need to be visited.
*
* For most strategies, nothing matches an empty search key, and
* an empty range never matches a non-empty key. If a strategy
* does not behave like that wrt. empty ranges, set strictEmpty to
* false.
*/
switch (strategy)
{
case RANGESTRAT_BEFORE:
/*
* Range A is before range B if upper bound of A is lower
* than lower bound of B.
*/
maxUpper = &lower;
inclusive = false;
break;
case RANGESTRAT_OVERLEFT:
/*
* Range A is overleft to range B if upper bound of A is
* less or equal to upper bound of B.
*/
maxUpper = &upper;
break;
case RANGESTRAT_OVERLAPS:
/*
* Non-empty ranges overlap, if lower bound of each range
* is lower or equal to upper bound of the other range.
*/
maxLower = &upper;
minUpper = &lower;
break;
case RANGESTRAT_OVERRIGHT:
/*
* Range A is overright to range B if lower bound of A is
* greater or equal to lower bound of B.
*/
minLower = &lower;
break;
case RANGESTRAT_AFTER:
/*
* Range A is after range B if lower bound of A is greater
* than upper bound of B.
*/
minLower = &upper;
inclusive = false;
break;
case RANGESTRAT_ADJACENT:
if (empty)
break; /* Skip to strictEmpty check. */
/*
* Previously selected quadrant could exclude possibility
* for lower or upper bounds to be adjacent. Deserialize
* previous centroid range if present for checking this.
*/
if (in->traversalValue)
{
prevCentroid = DatumGetRangeTypeP(in->traversalValue);
range_deserialize(typcache, prevCentroid,
&prevLower, &prevUpper, &prevEmpty);
}
/*
* For a range's upper bound to be adjacent to the
* argument's lower bound, it will be found along the line
* adjacent to (and just below) Y=lower. Therefore, if the
* argument's lower bound is less than the centroid's
* upper bound, the line falls in quadrants 2 and 3; if
* greater, the line falls in quadrants 1 and 4. (see
* adjacent_cmp_bounds for description of edge cases).
*/
cmp = adjacent_inner_consistent(typcache, &lower,
&centroidUpper,
prevCentroid ? &prevUpper : NULL);
if (cmp > 0)
which1 = (1 << 1) | (1 << 4);
else if (cmp < 0)
which1 = (1 << 2) | (1 << 3);
else
which1 = 0;
/*
* Also search for ranges's adjacent to argument's upper
* bound. They will be found along the line adjacent to
* (and just right of) X=upper, which falls in quadrants 3
* and 4, or 1 and 2.
*/
cmp = adjacent_inner_consistent(typcache, &upper,
&centroidLower,
prevCentroid ? &prevLower : NULL);
if (cmp > 0)
which2 = (1 << 1) | (1 << 2);
else if (cmp < 0)
which2 = (1 << 3) | (1 << 4);
else
which2 = 0;
/* We must chase down ranges adjacent to either bound. */
which &= which1 | which2;
needPrevious = true;
break;
case RANGESTRAT_CONTAINS:
/*
* Non-empty range A contains non-empty range B if lower
* bound of A is lower or equal to lower bound of range B
* and upper bound of range A is greater or equal to upper
* bound of range A.
*
* All non-empty ranges contain an empty range.
*/
strictEmpty = false;
if (!empty)
{
which &= (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4);
maxLower = &lower;
minUpper = &upper;
}
break;
case RANGESTRAT_CONTAINED_BY:
/* The opposite of contains. */
strictEmpty = false;
if (empty)
{
/* An empty range is only contained by an empty range */
which &= (1 << 5);
}
else
{
minLower = &lower;
maxUpper = &upper;
}
break;
case RANGESTRAT_EQ:
/*
* Equal range can be only in the same quadrant where
* argument would be placed to.
*/
strictEmpty = false;
which &= (1 << getQuadrant(typcache, centroid, range));
break;
default:
elog(ERROR, "unrecognized range strategy: %d", strategy);
break;
}
if (strictEmpty)
{
if (empty)
{
/* Scan key is empty, no branches are satisfying */
which = 0;
break;
}
else
{
/* Shouldn't visit tree branch with empty ranges */
which &= (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4);
}
}
/*
* Using the bounding box, see which quadrants we have to descend
* into.
*/
if (minLower)
{
/*
* If the centroid's lower bound is less than or equal to the
* minimum lower bound, anything in the 3rd and 4th quadrants
* will have an even smaller lower bound, and thus can't
* match.
*/
if (range_cmp_bounds(typcache, &centroidLower, minLower) <= 0)
which &= (1 << 1) | (1 << 2) | (1 << 5);
}
if (maxLower)
{
/*
* If the centroid's lower bound is greater than the maximum
* lower bound, anything in the 1st and 2nd quadrants will
* also have a greater than or equal lower bound, and thus
* can't match. If the centroid's lower bound is equal to the
* maximum lower bound, we can still exclude the 1st and 2nd
* quadrants if we're looking for a value strictly greater
* than the maximum.
*/
int cmp;
cmp = range_cmp_bounds(typcache, &centroidLower, maxLower);
if (cmp > 0 || (!inclusive && cmp == 0))
which &= (1 << 3) | (1 << 4) | (1 << 5);
}
if (minUpper)
{
/*
* If the centroid's upper bound is less than or equal to the
* minimum upper bound, anything in the 2nd and 3rd quadrants
* will have an even smaller upper bound, and thus can't
* match.
*/
if (range_cmp_bounds(typcache, &centroidUpper, minUpper) <= 0)
which &= (1 << 1) | (1 << 4) | (1 << 5);
}
if (maxUpper)
{
/*
* If the centroid's upper bound is greater than the maximum
* upper bound, anything in the 1st and 4th quadrants will
* also have a greater than or equal upper bound, and thus
* can't match. If the centroid's upper bound is equal to the
* maximum upper bound, we can still exclude the 1st and 4th
* quadrants if we're looking for a value strictly greater
* than the maximum.
*/
int cmp;
cmp = range_cmp_bounds(typcache, &centroidUpper, maxUpper);
if (cmp > 0 || (!inclusive && cmp == 0))
which &= (1 << 2) | (1 << 3) | (1 << 5);
}
if (which == 0)
break; /* no need to consider remaining conditions */
}
}
/* We must descend into the quadrant(s) identified by 'which' */
out->nodeNumbers = (int *) palloc(sizeof(int) * in->nNodes);
if (needPrevious)
out->traversalValues = (void **) palloc(sizeof(void *) * in->nNodes);
out->nNodes = 0;
/*
* Elements of traversalValues should be allocated in
* traversalMemoryContext
*/
oldCtx = MemoryContextSwitchTo(in->traversalMemoryContext);
for (i = 1; i <= in->nNodes; i++)
{
if (which & (1 << i))
{
/* Save previous prefix if needed */
if (needPrevious)
{
Datum previousCentroid;
/*
* We know, that in->prefixDatum in this place is varlena,
* because it's range
*/
previousCentroid = datumCopy(in->prefixDatum, false, -1);
out->traversalValues[out->nNodes] = (void *) previousCentroid;
}
out->nodeNumbers[out->nNodes] = i - 1;
out->nNodes++;
}
}
MemoryContextSwitchTo(oldCtx);
PG_RETURN_VOID();
}
/*
* adjacent_cmp_bounds
*
* Given an argument and centroid bound, this function determines if any
* bounds that are adjacent to the argument are smaller than, or greater than
* or equal to centroid. For brevity, we call the arg < centroid "left", and
* arg >= centroid case "right". This corresponds to how the quadrants are
* arranged, if you imagine that "left" is equivalent to "down" and "right"
* is equivalent to "up".
*
* For the "left" case, returns -1, and for the "right" case, returns 1.
*/
static int
adjacent_cmp_bounds(TypeCacheEntry *typcache, const RangeBound *arg,
const RangeBound *centroid)
{
int cmp;
Assert(arg->lower != centroid->lower);
cmp = range_cmp_bounds(typcache, arg, centroid);
if (centroid->lower)
{
/*------
* The argument is an upper bound, we are searching for adjacent lower
* bounds. A matching adjacent lower bound must be *larger* than the
* argument, but only just.
*
* The following table illustrates the desired result with a fixed
* argument bound, and different centroids. The CMP column shows
* the value of 'cmp' variable, and ADJ shows whether the argument
* and centroid are adjacent, per bounds_adjacent(). (N) means we
* don't need to check for that case, because it's implied by CMP.
* With the argument range [..., 500), the adjacent range we're
* searching for is [500, ...):
*
* ARGUMENT CENTROID CMP ADJ
* [..., 500) [498, ...) > (N) [500, ...) is to the right
* [..., 500) [499, ...) = (N) [500, ...) is to the right
* [..., 500) [500, ...) < Y [500, ...) is to the right
* [..., 500) [501, ...) < N [500, ...) is to the left
*
* So, we must search left when the argument is smaller than, and not
* adjacent, to the centroid. Otherwise search right.
*------
*/
if (cmp < 0 && !bounds_adjacent(typcache, *arg, *centroid))
return -1;
else
return 1;
}
else
{
/*------
* The argument is a lower bound, we are searching for adjacent upper
* bounds. A matching adjacent upper bound must be *smaller* than the
* argument, but only just.
*
* ARGUMENT CENTROID CMP ADJ
* [500, ...) [..., 499) > (N) [..., 500) is to the right
* [500, ...) [..., 500) > (Y) [..., 500) is to the right
* [500, ...) [..., 501) = (N) [..., 500) is to the left
* [500, ...) [..., 502) < (N) [..., 500) is to the left
*
* We must search left when the argument is smaller than or equal to
* the centroid. Otherwise search right. We don't need to check
* whether the argument is adjacent with the centroid, because it
* doesn't matter.
*------
*/
if (cmp <= 0)
return -1;
else
return 1;
}
}
/*----------
* adjacent_inner_consistent
*
* Like adjacent_cmp_bounds, but also takes into account the previous
* level's centroid. We might've traversed left (or right) at the previous
* node, in search for ranges adjacent to the other bound, even though we
* already ruled out the possibility for any matches in that direction for
* this bound. By comparing the argument with the previous centroid, and
* the previous centroid with the current centroid, we can determine which
* direction we should've moved in at previous level, and which direction we
* actually moved.
*
* If there can be any matches to the left, returns -1. If to the right,
* returns 1. If there can be no matches below this centroid, because we
* already ruled them out at the previous level, returns 0.
*
* XXX: Comparing just the previous and current level isn't foolproof; we
* might still search some branches unnecessarily. For example, imagine that
* we are searching for value 15, and we traverse the following centroids
* (only considering one bound for the moment):
*
* Level 1: 20
* Level 2: 50
* Level 3: 25
*
* At this point, previous centroid is 50, current centroid is 25, and the
* target value is to the left. But because we already moved right from
* centroid 20 to 50 in the first level, there cannot be any values < 20 in
* the current branch. But we don't know that just by looking at the previous
* and current centroid, so we traverse left, unnecessarily. The reason we are
* down this branch is that we're searching for matches with the *other*
* bound. If we kept track of which bound we are searching for explicitly,
* instead of deducing that from the previous and current centroid, we could
* avoid some unnecessary work.
*----------
*/
static int
adjacent_inner_consistent(TypeCacheEntry *typcache, const RangeBound *arg,
const RangeBound *centroid, const RangeBound *prev)
{
if (prev)
{
int prevcmp;
int cmp;
/*
* Which direction were we supposed to traverse at previous level,
* left or right?
*/
prevcmp = adjacent_cmp_bounds(typcache, arg, prev);
/* and which direction did we actually go? */
cmp = range_cmp_bounds(typcache, centroid, prev);
/* if the two don't agree, there's nothing to see here */
if ((prevcmp < 0 && cmp >= 0) || (prevcmp > 0 && cmp < 0))
return 0;
}
return adjacent_cmp_bounds(typcache, arg, centroid);
}
/*
* SP-GiST consistent function for leaf nodes: check leaf value against query
* using corresponding function.
*/
Datum
spg_range_quad_leaf_consistent(PG_FUNCTION_ARGS)
{
spgLeafConsistentIn *in = (spgLeafConsistentIn *) PG_GETARG_POINTER(0);
spgLeafConsistentOut *out = (spgLeafConsistentOut *) PG_GETARG_POINTER(1);
RangeType *leafRange = DatumGetRangeTypeP(in->leafDatum);
TypeCacheEntry *typcache;
bool res;
int i;
/* all tests are exact */
out->recheck = false;
/* leafDatum is what it is... */
out->leafValue = in->leafDatum;
typcache = range_get_typcache(fcinfo, RangeTypeGetOid(leafRange));
/* Perform the required comparison(s) */
res = true;
for (i = 0; i < in->nkeys; i++)
{
Datum keyDatum = in->scankeys[i].sk_argument;
/* Call the function corresponding to the scan strategy */
switch (in->scankeys[i].sk_strategy)
{
case RANGESTRAT_BEFORE:
res = range_before_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_OVERLEFT:
res = range_overleft_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_OVERLAPS:
res = range_overlaps_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_OVERRIGHT:
res = range_overright_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_AFTER:
res = range_after_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_ADJACENT:
res = range_adjacent_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_CONTAINS:
res = range_contains_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_CONTAINED_BY:
res = range_contained_by_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
case RANGESTRAT_CONTAINS_ELEM:
res = range_contains_elem_internal(typcache, leafRange,
keyDatum);
break;
case RANGESTRAT_EQ:
res = range_eq_internal(typcache, leafRange,
DatumGetRangeTypeP(keyDatum));
break;
default:
elog(ERROR, "unrecognized range strategy: %d",
in->scankeys[i].sk_strategy);
break;
}
/*
* If leaf datum doesn't match to a query key, no need to check
* subsequent keys.
*/
if (!res)
break;
}
PG_RETURN_BOOL(res);
}
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