Age Owner Branch data 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) 1996-2024, 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
8714 tgl@sss.pgh.pa.us 48 :CBC 104 : areasel(PG_FUNCTION_ARGS)
49 : : {
8459 50 : 104 : PG_RETURN_FLOAT8(0.005);
51 : : }
52 : :
53 : : Datum
8714 54 : 33 : areajoinsel(PG_FUNCTION_ARGS)
55 : : {
8459 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
8714 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 : : {
8459 88 : 338 : PG_RETURN_FLOAT8(0.001);
89 : : }
90 : :
91 : : Datum
8714 92 : 15 : contjoinsel(PG_FUNCTION_ARGS)
93 : : {
8459 94 : 15 : PG_RETURN_FLOAT8(0.001);
95 : : }
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