Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * _int_selfuncs.c
4 : * Functions for selectivity estimation of intarray operators
5 : *
6 : * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * contrib/intarray/_int_selfuncs.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "_int.h"
18 : #include "access/htup_details.h"
19 : #include "catalog/pg_operator.h"
20 : #include "catalog/pg_statistic.h"
21 : #include "catalog/pg_type.h"
22 : #include "miscadmin.h"
23 : #include "utils/fmgrprotos.h"
24 : #include "utils/lsyscache.h"
25 : #include "utils/selfuncs.h"
26 :
27 4 : PG_FUNCTION_INFO_V1(_int_overlap_sel);
28 4 : PG_FUNCTION_INFO_V1(_int_contains_sel);
29 4 : PG_FUNCTION_INFO_V1(_int_contained_sel);
30 2 : PG_FUNCTION_INFO_V1(_int_overlap_joinsel);
31 2 : PG_FUNCTION_INFO_V1(_int_contains_joinsel);
32 2 : PG_FUNCTION_INFO_V1(_int_contained_joinsel);
33 4 : PG_FUNCTION_INFO_V1(_int_matchsel);
34 :
35 :
36 : static Selectivity int_query_opr_selec(ITEM *item, Datum *mcelems, float4 *mcefreqs,
37 : int nmcelems, float4 minfreq);
38 : static int compare_val_int4(const void *a, const void *b);
39 :
40 : /*
41 : * Wrappers around the default array selectivity estimation functions.
42 : *
43 : * The default array selectivity operators for the @>, && and @< operators
44 : * work fine for integer arrays. However, if we tried to just use arraycontsel
45 : * and arraycontjoinsel directly as the cost estimator functions for our
46 : * operators, they would not work as intended, because they look at the
47 : * operator's OID. Our operators behave exactly like the built-in anyarray
48 : * versions, but we must tell the cost estimator functions which built-in
49 : * operators they correspond to. These wrappers just replace the operator
50 : * OID with the corresponding built-in operator's OID, and call the built-in
51 : * function.
52 : */
53 :
54 : Datum
55 14 : _int_overlap_sel(PG_FUNCTION_ARGS)
56 : {
57 14 : PG_RETURN_DATUM(DirectFunctionCall4(arraycontsel,
58 : PG_GETARG_DATUM(0),
59 : ObjectIdGetDatum(OID_ARRAY_OVERLAP_OP),
60 : PG_GETARG_DATUM(2),
61 : PG_GETARG_DATUM(3)));
62 : }
63 :
64 : Datum
65 56 : _int_contains_sel(PG_FUNCTION_ARGS)
66 : {
67 56 : PG_RETURN_DATUM(DirectFunctionCall4(arraycontsel,
68 : PG_GETARG_DATUM(0),
69 : ObjectIdGetDatum(OID_ARRAY_CONTAINS_OP),
70 : PG_GETARG_DATUM(2),
71 : PG_GETARG_DATUM(3)));
72 : }
73 :
74 : Datum
75 14 : _int_contained_sel(PG_FUNCTION_ARGS)
76 : {
77 14 : PG_RETURN_DATUM(DirectFunctionCall4(arraycontsel,
78 : PG_GETARG_DATUM(0),
79 : ObjectIdGetDatum(OID_ARRAY_CONTAINED_OP),
80 : PG_GETARG_DATUM(2),
81 : PG_GETARG_DATUM(3)));
82 : }
83 :
84 : Datum
85 0 : _int_overlap_joinsel(PG_FUNCTION_ARGS)
86 : {
87 0 : PG_RETURN_DATUM(DirectFunctionCall5(arraycontjoinsel,
88 : PG_GETARG_DATUM(0),
89 : ObjectIdGetDatum(OID_ARRAY_OVERLAP_OP),
90 : PG_GETARG_DATUM(2),
91 : PG_GETARG_DATUM(3),
92 : PG_GETARG_DATUM(4)));
93 : }
94 :
95 : Datum
96 0 : _int_contains_joinsel(PG_FUNCTION_ARGS)
97 : {
98 0 : PG_RETURN_DATUM(DirectFunctionCall5(arraycontjoinsel,
99 : PG_GETARG_DATUM(0),
100 : ObjectIdGetDatum(OID_ARRAY_CONTAINS_OP),
101 : PG_GETARG_DATUM(2),
102 : PG_GETARG_DATUM(3),
103 : PG_GETARG_DATUM(4)));
104 : }
105 :
106 : Datum
107 0 : _int_contained_joinsel(PG_FUNCTION_ARGS)
108 : {
109 0 : PG_RETURN_DATUM(DirectFunctionCall5(arraycontjoinsel,
110 : PG_GETARG_DATUM(0),
111 : ObjectIdGetDatum(OID_ARRAY_CONTAINED_OP),
112 : PG_GETARG_DATUM(2),
113 : PG_GETARG_DATUM(3),
114 : PG_GETARG_DATUM(4)));
115 : }
116 :
117 :
118 : /*
119 : * _int_matchsel -- restriction selectivity function for intarray @@ query_int
120 : */
121 : Datum
122 84 : _int_matchsel(PG_FUNCTION_ARGS)
123 : {
124 84 : PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
125 :
126 84 : List *args = (List *) PG_GETARG_POINTER(2);
127 84 : int varRelid = PG_GETARG_INT32(3);
128 : VariableStatData vardata;
129 : Node *other;
130 : bool varonleft;
131 : Selectivity selec;
132 : QUERYTYPE *query;
133 84 : Datum *mcelems = NULL;
134 84 : float4 *mcefreqs = NULL;
135 84 : int nmcelems = 0;
136 84 : float4 minfreq = 0.0;
137 84 : float4 nullfrac = 0.0;
138 : AttStatsSlot sslot;
139 :
140 : /*
141 : * If expression is not "variable @@ something" or "something @@ variable"
142 : * then punt and return a default estimate.
143 : */
144 84 : if (!get_restriction_variable(root, args, varRelid,
145 : &vardata, &other, &varonleft))
146 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
147 :
148 : /*
149 : * Variable should be int[]. We don't support cases where variable is
150 : * query_int.
151 : */
152 84 : if (vardata.vartype != INT4ARRAYOID)
153 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
154 :
155 : /*
156 : * Can't do anything useful if the something is not a constant, either.
157 : */
158 84 : if (!IsA(other, Const))
159 : {
160 0 : ReleaseVariableStats(vardata);
161 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
162 : }
163 :
164 : /*
165 : * The "@@" operator is strict, so we can cope with NULL right away.
166 : */
167 84 : if (((Const *) other)->constisnull)
168 : {
169 0 : ReleaseVariableStats(vardata);
170 0 : PG_RETURN_FLOAT8(0.0);
171 : }
172 :
173 : /* The caller made sure the const is a query, so get it now */
174 84 : query = DatumGetQueryTypeP(((Const *) other)->constvalue);
175 :
176 : /* Empty query matches nothing */
177 84 : if (query->size == 0)
178 : {
179 0 : ReleaseVariableStats(vardata);
180 0 : return (Selectivity) 0.0;
181 : }
182 :
183 : /*
184 : * Get the statistics for the intarray column.
185 : *
186 : * We're interested in the Most-Common-Elements list, and the NULL
187 : * fraction.
188 : */
189 84 : if (HeapTupleIsValid(vardata.statsTuple))
190 : {
191 : Form_pg_statistic stats;
192 :
193 72 : stats = (Form_pg_statistic) GETSTRUCT(vardata.statsTuple);
194 72 : nullfrac = stats->stanullfrac;
195 :
196 : /*
197 : * For an int4 array, the default array type analyze function will
198 : * collect a Most Common Elements list, which is an array of int4s.
199 : */
200 72 : if (get_attstatsslot(&sslot, vardata.statsTuple,
201 : STATISTIC_KIND_MCELEM, InvalidOid,
202 : ATTSTATSSLOT_VALUES | ATTSTATSSLOT_NUMBERS))
203 : {
204 : Assert(sslot.valuetype == INT4OID);
205 :
206 : /*
207 : * There should be three more Numbers than Values, because the
208 : * last three (for intarray) cells are taken for minimal, maximal
209 : * and nulls frequency. Punt if not.
210 : */
211 72 : if (sslot.nnumbers == sslot.nvalues + 3)
212 : {
213 : /* Grab the lowest frequency. */
214 72 : minfreq = sslot.numbers[sslot.nnumbers - (sslot.nnumbers - sslot.nvalues)];
215 :
216 72 : mcelems = sslot.values;
217 72 : mcefreqs = sslot.numbers;
218 72 : nmcelems = sslot.nvalues;
219 : }
220 : }
221 : }
222 : else
223 12 : memset(&sslot, 0, sizeof(sslot));
224 :
225 : /* Process the logical expression in the query, using the stats */
226 84 : selec = int_query_opr_selec(GETQUERY(query) + query->size - 1,
227 : mcelems, mcefreqs, nmcelems, minfreq);
228 :
229 : /* MCE stats count only non-null rows, so adjust for null rows. */
230 84 : selec *= (1.0 - nullfrac);
231 :
232 84 : free_attstatsslot(&sslot);
233 84 : ReleaseVariableStats(vardata);
234 :
235 84 : CLAMP_PROBABILITY(selec);
236 :
237 84 : PG_RETURN_FLOAT8((float8) selec);
238 : }
239 :
240 : /*
241 : * Estimate selectivity of single intquery operator
242 : */
243 : static Selectivity
244 350 : int_query_opr_selec(ITEM *item, Datum *mcelems, float4 *mcefreqs,
245 : int nmcelems, float4 minfreq)
246 : {
247 : Selectivity selec;
248 :
249 : /* since this function recurses, it could be driven to stack overflow */
250 350 : check_stack_depth();
251 :
252 350 : if (item->type == VAL)
253 : {
254 : Datum *searchres;
255 :
256 196 : if (mcelems == NULL)
257 28 : return (Selectivity) DEFAULT_EQ_SEL;
258 :
259 168 : searchres = (Datum *) bsearch(&item->val, mcelems, nmcelems,
260 : sizeof(Datum), compare_val_int4);
261 168 : if (searchres)
262 : {
263 : /*
264 : * The element is in MCELEM. Return precise selectivity (or at
265 : * least as precise as ANALYZE could find out).
266 : */
267 168 : selec = mcefreqs[searchres - mcelems];
268 : }
269 : else
270 : {
271 : /*
272 : * The element is not in MCELEM. Punt, but assume that the
273 : * selectivity cannot be more than minfreq / 2.
274 : */
275 0 : selec = Min(DEFAULT_EQ_SEL, minfreq / 2);
276 : }
277 : }
278 154 : else if (item->type == OPR)
279 : {
280 : /* Current query node is an operator */
281 : Selectivity s1,
282 : s2;
283 :
284 154 : s1 = int_query_opr_selec(item - 1, mcelems, mcefreqs, nmcelems,
285 : minfreq);
286 154 : switch (item->val)
287 : {
288 42 : case (int32) '!':
289 42 : selec = 1.0 - s1;
290 42 : break;
291 :
292 70 : case (int32) '&':
293 70 : s2 = int_query_opr_selec(item + item->left, mcelems, mcefreqs,
294 : nmcelems, minfreq);
295 70 : selec = s1 * s2;
296 70 : break;
297 :
298 42 : case (int32) '|':
299 42 : s2 = int_query_opr_selec(item + item->left, mcelems, mcefreqs,
300 : nmcelems, minfreq);
301 42 : selec = s1 + s2 - s1 * s2;
302 42 : break;
303 :
304 0 : default:
305 0 : elog(ERROR, "unrecognized operator: %d", item->val);
306 : selec = 0; /* keep compiler quiet */
307 : break;
308 : }
309 : }
310 : else
311 : {
312 0 : elog(ERROR, "unrecognized int query item type: %u", item->type);
313 : selec = 0; /* keep compiler quiet */
314 : }
315 :
316 : /* Clamp intermediate results to stay sane despite roundoff error */
317 322 : CLAMP_PROBABILITY(selec);
318 :
319 322 : return selec;
320 : }
321 :
322 : /*
323 : * Comparison function for binary search in mcelem array.
324 : */
325 : static int
326 1200 : compare_val_int4(const void *a, const void *b)
327 : {
328 1200 : int32 key = *(int32 *) a;
329 1200 : const Datum *t = (const Datum *) b;
330 :
331 1200 : return key - DatumGetInt32(*t);
332 : }
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