1 /*-------------------------------------------------------------------------
2 *
3 * spgkdtreeproc.c
4 * implementation of k-d tree over points for SP-GiST
5 *
6 *
7 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
9 *
10 * IDENTIFICATION
11 * src/backend/access/spgist/spgkdtreeproc.c
12 *
13 *-------------------------------------------------------------------------
14 */
15
16 #include "postgres.h"
17
18 #include "access/spgist.h"
19 #include "access/spgist_private.h"
20 #include "access/stratnum.h"
21 #include "catalog/pg_type.h"
22 #include "utils/builtins.h"
23 #include "utils/float.h"
24 #include "utils/geo_decls.h"
25
26
27 Datum
spg_kd_config(PG_FUNCTION_ARGS)28 spg_kd_config(PG_FUNCTION_ARGS)
29 {
30 /* spgConfigIn *cfgin = (spgConfigIn *) PG_GETARG_POINTER(0); */
31 spgConfigOut *cfg = (spgConfigOut *) PG_GETARG_POINTER(1);
32
33 cfg->prefixType = FLOAT8OID;
34 cfg->labelType = VOIDOID; /* we don't need node labels */
35 cfg->canReturnData = true;
36 cfg->longValuesOK = false;
37 PG_RETURN_VOID();
38 }
39
40 static int
getSide(double coord,bool isX,Point * tst)41 getSide(double coord, bool isX, Point *tst)
42 {
43 double tstcoord = (isX) ? tst->x : tst->y;
44
45 if (coord == tstcoord)
46 return 0;
47 else if (coord > tstcoord)
48 return 1;
49 else
50 return -1;
51 }
52
53 Datum
spg_kd_choose(PG_FUNCTION_ARGS)54 spg_kd_choose(PG_FUNCTION_ARGS)
55 {
56 spgChooseIn *in = (spgChooseIn *) PG_GETARG_POINTER(0);
57 spgChooseOut *out = (spgChooseOut *) PG_GETARG_POINTER(1);
58 Point *inPoint = DatumGetPointP(in->datum);
59 double coord;
60
61 if (in->allTheSame)
62 elog(ERROR, "allTheSame should not occur for k-d trees");
63
64 Assert(in->hasPrefix);
65 coord = DatumGetFloat8(in->prefixDatum);
66
67 Assert(in->nNodes == 2);
68
69 out->resultType = spgMatchNode;
70 out->result.matchNode.nodeN =
71 (getSide(coord, in->level % 2, inPoint) > 0) ? 0 : 1;
72 out->result.matchNode.levelAdd = 1;
73 out->result.matchNode.restDatum = PointPGetDatum(inPoint);
74
75 PG_RETURN_VOID();
76 }
77
78 typedef struct SortedPoint
79 {
80 Point *p;
81 int i;
82 } SortedPoint;
83
84 static int
x_cmp(const void * a,const void * b)85 x_cmp(const void *a, const void *b)
86 {
87 SortedPoint *pa = (SortedPoint *) a;
88 SortedPoint *pb = (SortedPoint *) b;
89
90 if (pa->p->x == pb->p->x)
91 return 0;
92 return (pa->p->x > pb->p->x) ? 1 : -1;
93 }
94
95 static int
y_cmp(const void * a,const void * b)96 y_cmp(const void *a, const void *b)
97 {
98 SortedPoint *pa = (SortedPoint *) a;
99 SortedPoint *pb = (SortedPoint *) b;
100
101 if (pa->p->y == pb->p->y)
102 return 0;
103 return (pa->p->y > pb->p->y) ? 1 : -1;
104 }
105
106
107 Datum
spg_kd_picksplit(PG_FUNCTION_ARGS)108 spg_kd_picksplit(PG_FUNCTION_ARGS)
109 {
110 spgPickSplitIn *in = (spgPickSplitIn *) PG_GETARG_POINTER(0);
111 spgPickSplitOut *out = (spgPickSplitOut *) PG_GETARG_POINTER(1);
112 int i;
113 int middle;
114 SortedPoint *sorted;
115 double coord;
116
117 sorted = palloc(sizeof(*sorted) * in->nTuples);
118 for (i = 0; i < in->nTuples; i++)
119 {
120 sorted[i].p = DatumGetPointP(in->datums[i]);
121 sorted[i].i = i;
122 }
123
124 qsort(sorted, in->nTuples, sizeof(*sorted),
125 (in->level % 2) ? x_cmp : y_cmp);
126 middle = in->nTuples >> 1;
127 coord = (in->level % 2) ? sorted[middle].p->x : sorted[middle].p->y;
128
129 out->hasPrefix = true;
130 out->prefixDatum = Float8GetDatum(coord);
131
132 out->nNodes = 2;
133 out->nodeLabels = NULL; /* we don't need node labels */
134
135 out->mapTuplesToNodes = palloc(sizeof(int) * in->nTuples);
136 out->leafTupleDatums = palloc(sizeof(Datum) * in->nTuples);
137
138 /*
139 * Note: points that have coordinates exactly equal to coord may get
140 * classified into either node, depending on where they happen to fall in
141 * the sorted list. This is okay as long as the inner_consistent function
142 * descends into both sides for such cases. This is better than the
143 * alternative of trying to have an exact boundary, because it keeps the
144 * tree balanced even when we have many instances of the same point value.
145 * So we should never trigger the allTheSame logic.
146 */
147 for (i = 0; i < in->nTuples; i++)
148 {
149 Point *p = sorted[i].p;
150 int n = sorted[i].i;
151
152 out->mapTuplesToNodes[n] = (i < middle) ? 0 : 1;
153 out->leafTupleDatums[n] = PointPGetDatum(p);
154 }
155
156 PG_RETURN_VOID();
157 }
158
159 Datum
spg_kd_inner_consistent(PG_FUNCTION_ARGS)160 spg_kd_inner_consistent(PG_FUNCTION_ARGS)
161 {
162 spgInnerConsistentIn *in = (spgInnerConsistentIn *) PG_GETARG_POINTER(0);
163 spgInnerConsistentOut *out = (spgInnerConsistentOut *) PG_GETARG_POINTER(1);
164 double coord;
165 int which;
166 int i;
167 BOX bboxes[2];
168
169 Assert(in->hasPrefix);
170 coord = DatumGetFloat8(in->prefixDatum);
171
172 if (in->allTheSame)
173 elog(ERROR, "allTheSame should not occur for k-d trees");
174
175 Assert(in->nNodes == 2);
176
177 /* "which" is a bitmask of children that satisfy all constraints */
178 which = (1 << 1) | (1 << 2);
179
180 for (i = 0; i < in->nkeys; i++)
181 {
182 Point *query = DatumGetPointP(in->scankeys[i].sk_argument);
183 BOX *boxQuery;
184
185 switch (in->scankeys[i].sk_strategy)
186 {
187 case RTLeftStrategyNumber:
188 if ((in->level % 2) != 0 && FPlt(query->x, coord))
189 which &= (1 << 1);
190 break;
191 case RTRightStrategyNumber:
192 if ((in->level % 2) != 0 && FPgt(query->x, coord))
193 which &= (1 << 2);
194 break;
195 case RTSameStrategyNumber:
196 if ((in->level % 2) != 0)
197 {
198 if (FPlt(query->x, coord))
199 which &= (1 << 1);
200 else if (FPgt(query->x, coord))
201 which &= (1 << 2);
202 }
203 else
204 {
205 if (FPlt(query->y, coord))
206 which &= (1 << 1);
207 else if (FPgt(query->y, coord))
208 which &= (1 << 2);
209 }
210 break;
211 case RTBelowStrategyNumber:
212 case RTOldBelowStrategyNumber:
213 if ((in->level % 2) == 0 && FPlt(query->y, coord))
214 which &= (1 << 1);
215 break;
216 case RTAboveStrategyNumber:
217 case RTOldAboveStrategyNumber:
218 if ((in->level % 2) == 0 && FPgt(query->y, coord))
219 which &= (1 << 2);
220 break;
221 case RTContainedByStrategyNumber:
222
223 /*
224 * For this operator, the query is a box not a point. We
225 * cheat to the extent of assuming that DatumGetPointP won't
226 * do anything that would be bad for a pointer-to-box.
227 */
228 boxQuery = DatumGetBoxP(in->scankeys[i].sk_argument);
229
230 if ((in->level % 2) != 0)
231 {
232 if (FPlt(boxQuery->high.x, coord))
233 which &= (1 << 1);
234 else if (FPgt(boxQuery->low.x, coord))
235 which &= (1 << 2);
236 }
237 else
238 {
239 if (FPlt(boxQuery->high.y, coord))
240 which &= (1 << 1);
241 else if (FPgt(boxQuery->low.y, coord))
242 which &= (1 << 2);
243 }
244 break;
245 default:
246 elog(ERROR, "unrecognized strategy number: %d",
247 in->scankeys[i].sk_strategy);
248 break;
249 }
250
251 if (which == 0)
252 break; /* no need to consider remaining conditions */
253 }
254
255 /* We must descend into the children identified by which */
256 out->nNodes = 0;
257
258 /* Fast-path for no matching children */
259 if (!which)
260 PG_RETURN_VOID();
261
262 out->nodeNumbers = (int *) palloc(sizeof(int) * 2);
263
264 /*
265 * When ordering scan keys are specified, we've to calculate distance for
266 * them. In order to do that, we need calculate bounding boxes for both
267 * children nodes. Calculation of those bounding boxes on non-zero level
268 * require knowledge of bounding box of upper node. So, we save bounding
269 * boxes to traversalValues.
270 */
271 if (in->norderbys > 0)
272 {
273 BOX infArea;
274 BOX *area;
275
276 out->distances = (double **) palloc(sizeof(double *) * in->nNodes);
277 out->traversalValues = (void **) palloc(sizeof(void *) * in->nNodes);
278
279 if (in->level == 0)
280 {
281 float8 inf = get_float8_infinity();
282
283 infArea.high.x = inf;
284 infArea.high.y = inf;
285 infArea.low.x = -inf;
286 infArea.low.y = -inf;
287 area = &infArea;
288 }
289 else
290 {
291 area = (BOX *) in->traversalValue;
292 Assert(area);
293 }
294
295 bboxes[0].low = area->low;
296 bboxes[1].high = area->high;
297
298 if (in->level % 2)
299 {
300 /* split box by x */
301 bboxes[0].high.x = bboxes[1].low.x = coord;
302 bboxes[0].high.y = area->high.y;
303 bboxes[1].low.y = area->low.y;
304 }
305 else
306 {
307 /* split box by y */
308 bboxes[0].high.y = bboxes[1].low.y = coord;
309 bboxes[0].high.x = area->high.x;
310 bboxes[1].low.x = area->low.x;
311 }
312 }
313
314 for (i = 1; i <= 2; i++)
315 {
316 if (which & (1 << i))
317 {
318 out->nodeNumbers[out->nNodes] = i - 1;
319
320 if (in->norderbys > 0)
321 {
322 MemoryContext oldCtx = MemoryContextSwitchTo(in->traversalMemoryContext);
323 BOX *box = box_copy(&bboxes[i - 1]);
324
325 MemoryContextSwitchTo(oldCtx);
326
327 out->traversalValues[out->nNodes] = box;
328
329 out->distances[out->nNodes] = spg_key_orderbys_distances(BoxPGetDatum(box), false,
330 in->orderbys, in->norderbys);
331 }
332
333 out->nNodes++;
334 }
335 }
336
337 /* Set up level increments, too */
338 out->levelAdds = (int *) palloc(sizeof(int) * 2);
339 out->levelAdds[0] = 1;
340 out->levelAdds[1] = 1;
341
342 PG_RETURN_VOID();
343 }
344
345 /*
346 * spg_kd_leaf_consistent() is the same as spg_quad_leaf_consistent(),
347 * since we support the same operators and the same leaf data type.
348 * So we just borrow that function.
349 */
350