Age Owner TLA Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * geo_selfuncs.c
4 : * Selectivity routines registered in the operator catalog in the
5 : * "oprrest" and "oprjoin" attributes.
6 : *
7 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : *
11 : * IDENTIFICATION
12 : * src/backend/utils/adt/geo_selfuncs.c
13 : *
14 : * XXX These are totally bogus. Perhaps someone will make them do
15 : * something reasonable, someday.
16 : *
17 : *-------------------------------------------------------------------------
18 : */
19 : #include "postgres.h"
20 :
21 : #include "utils/fmgrprotos.h"
22 :
23 :
24 : /*
25 : * Selectivity functions for geometric operators. These are bogus -- unless
26 : * we know the actual key distribution in the index, we can't make a good
27 : * prediction of the selectivity of these operators.
28 : *
29 : * Note: the values used here may look unreasonably small. Perhaps they
30 : * are. For now, we want to make sure that the optimizer will make use
31 : * of a geometric index if one is available, so the selectivity had better
32 : * be fairly small.
33 : *
34 : * In general, GiST needs to search multiple subtrees in order to guarantee
35 : * that all occurrences of the same key have been found. Because of this,
36 : * the estimated cost for scanning the index ought to be higher than the
37 : * output selectivity would indicate. gistcostestimate(), over in selfuncs.c,
38 : * ought to be adjusted accordingly --- but until we can generate somewhat
39 : * realistic numbers here, it hardly matters...
40 : */
41 :
42 :
43 : /*
44 : * Selectivity for operators that depend on area, such as "overlap".
45 : */
46 :
47 : Datum
9224 tgl@sss.pgh.pa.us 48 CBC 104 : areasel(PG_FUNCTION_ARGS)
49 : {
8969 50 104 : PG_RETURN_FLOAT8(0.005);
51 : }
52 :
53 : Datum
9224 54 33 : areajoinsel(PG_FUNCTION_ARGS)
55 : {
8969 56 33 : PG_RETURN_FLOAT8(0.005);
57 : }
58 :
59 : /*
60 : * positionsel
61 : *
62 : * How likely is a box to be strictly left of (right of, above, below)
63 : * a given box?
64 : */
65 :
66 : Datum
9224 67 467 : positionsel(PG_FUNCTION_ARGS)
68 : {
69 467 : PG_RETURN_FLOAT8(0.1);
70 : }
71 :
72 : Datum
73 57 : positionjoinsel(PG_FUNCTION_ARGS)
74 : {
75 57 : PG_RETURN_FLOAT8(0.1);
76 : }
77 :
78 : /*
79 : * contsel -- How likely is a box to contain (be contained by) a given box?
80 : *
81 : * This is a tighter constraint than "overlap", so produce a smaller
82 : * estimate than areasel does.
83 : */
84 :
85 : Datum
86 338 : contsel(PG_FUNCTION_ARGS)
87 : {
8969 88 338 : PG_RETURN_FLOAT8(0.001);
89 : }
90 :
91 : Datum
9224 92 15 : contjoinsel(PG_FUNCTION_ARGS)
93 : {
8969 94 15 : PG_RETURN_FLOAT8(0.001);
95 : }
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