Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * _int_selfuncs.c
4 : * Functions for selectivity estimation of intarray operators
5 : *
6 : * Portions Copyright (c) 1996-2026, 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 "commands/extension.h"
23 : #include "miscadmin.h"
24 : #include "utils/fmgrprotos.h"
25 : #include "utils/lsyscache.h"
26 : #include "utils/selfuncs.h"
27 :
28 4 : PG_FUNCTION_INFO_V1(_int_overlap_sel);
29 4 : PG_FUNCTION_INFO_V1(_int_contains_sel);
30 4 : PG_FUNCTION_INFO_V1(_int_contained_sel);
31 2 : PG_FUNCTION_INFO_V1(_int_overlap_joinsel);
32 2 : PG_FUNCTION_INFO_V1(_int_contains_joinsel);
33 2 : PG_FUNCTION_INFO_V1(_int_contained_joinsel);
34 4 : PG_FUNCTION_INFO_V1(_int_matchsel);
35 :
36 :
37 : static Selectivity int_query_opr_selec(ITEM *item, Datum *mcelems, float4 *mcefreqs,
38 : int nmcelems, float4 minfreq);
39 : static int compare_val_int4(const void *a, const void *b);
40 :
41 : /*
42 : * Wrappers around the default array selectivity estimation functions.
43 : *
44 : * The default array selectivity operators for the @>, && and @< operators
45 : * work fine for integer arrays. However, if we tried to just use arraycontsel
46 : * and arraycontjoinsel directly as the cost estimator functions for our
47 : * operators, they would not work as intended, because they look at the
48 : * operator's OID. Our operators behave exactly like the built-in anyarray
49 : * versions, but we must tell the cost estimator functions which built-in
50 : * operators they correspond to. These wrappers just replace the operator
51 : * OID with the corresponding built-in operator's OID, and call the built-in
52 : * function.
53 : */
54 :
55 : Datum
56 14 : _int_overlap_sel(PG_FUNCTION_ARGS)
57 : {
58 14 : PG_RETURN_DATUM(DirectFunctionCall4(arraycontsel,
59 : PG_GETARG_DATUM(0),
60 : ObjectIdGetDatum(OID_ARRAY_OVERLAP_OP),
61 : PG_GETARG_DATUM(2),
62 : PG_GETARG_DATUM(3)));
63 : }
64 :
65 : Datum
66 56 : _int_contains_sel(PG_FUNCTION_ARGS)
67 : {
68 56 : PG_RETURN_DATUM(DirectFunctionCall4(arraycontsel,
69 : PG_GETARG_DATUM(0),
70 : ObjectIdGetDatum(OID_ARRAY_CONTAINS_OP),
71 : PG_GETARG_DATUM(2),
72 : PG_GETARG_DATUM(3)));
73 : }
74 :
75 : Datum
76 14 : _int_contained_sel(PG_FUNCTION_ARGS)
77 : {
78 14 : PG_RETURN_DATUM(DirectFunctionCall4(arraycontsel,
79 : PG_GETARG_DATUM(0),
80 : ObjectIdGetDatum(OID_ARRAY_CONTAINED_OP),
81 : PG_GETARG_DATUM(2),
82 : PG_GETARG_DATUM(3)));
83 : }
84 :
85 : Datum
86 0 : _int_overlap_joinsel(PG_FUNCTION_ARGS)
87 : {
88 0 : PG_RETURN_DATUM(DirectFunctionCall5(arraycontjoinsel,
89 : PG_GETARG_DATUM(0),
90 : ObjectIdGetDatum(OID_ARRAY_OVERLAP_OP),
91 : PG_GETARG_DATUM(2),
92 : PG_GETARG_DATUM(3),
93 : PG_GETARG_DATUM(4)));
94 : }
95 :
96 : Datum
97 0 : _int_contains_joinsel(PG_FUNCTION_ARGS)
98 : {
99 0 : PG_RETURN_DATUM(DirectFunctionCall5(arraycontjoinsel,
100 : PG_GETARG_DATUM(0),
101 : ObjectIdGetDatum(OID_ARRAY_CONTAINS_OP),
102 : PG_GETARG_DATUM(2),
103 : PG_GETARG_DATUM(3),
104 : PG_GETARG_DATUM(4)));
105 : }
106 :
107 : Datum
108 0 : _int_contained_joinsel(PG_FUNCTION_ARGS)
109 : {
110 0 : PG_RETURN_DATUM(DirectFunctionCall5(arraycontjoinsel,
111 : PG_GETARG_DATUM(0),
112 : ObjectIdGetDatum(OID_ARRAY_CONTAINED_OP),
113 : PG_GETARG_DATUM(2),
114 : PG_GETARG_DATUM(3),
115 : PG_GETARG_DATUM(4)));
116 : }
117 :
118 :
119 : /*
120 : * _int_matchsel -- restriction selectivity function for intarray @@ query_int
121 : */
122 : Datum
123 98 : _int_matchsel(PG_FUNCTION_ARGS)
124 : {
125 98 : PlannerInfo *root = (PlannerInfo *) PG_GETARG_POINTER(0);
126 :
127 98 : List *args = (List *) PG_GETARG_POINTER(2);
128 98 : int varRelid = PG_GETARG_INT32(3);
129 : VariableStatData vardata;
130 : Node *other;
131 : bool varonleft;
132 : Selectivity selec;
133 : QUERYTYPE *query;
134 98 : Datum *mcelems = NULL;
135 98 : float4 *mcefreqs = NULL;
136 98 : int nmcelems = 0;
137 98 : float4 minfreq = 0.0;
138 98 : float4 nullfrac = 0.0;
139 : AttStatsSlot sslot;
140 :
141 : /*
142 : * If expression is not "variable @@ something" or "something @@ variable"
143 : * then punt and return a default estimate.
144 : */
145 98 : if (!get_restriction_variable(root, args, varRelid,
146 : &vardata, &other, &varonleft))
147 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
148 :
149 : /*
150 : * Variable should be int[]. We don't support cases where variable is
151 : * query_int.
152 : */
153 98 : if (vardata.vartype != INT4ARRAYOID)
154 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
155 :
156 : /*
157 : * Can't do anything useful if the something is not a constant, either.
158 : */
159 98 : if (!IsA(other, Const))
160 : {
161 0 : ReleaseVariableStats(vardata);
162 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
163 : }
164 :
165 : /*
166 : * The "@@" operator is strict, so we can cope with NULL right away.
167 : */
168 98 : if (((Const *) other)->constisnull)
169 : {
170 0 : ReleaseVariableStats(vardata);
171 0 : PG_RETURN_FLOAT8(0.0);
172 : }
173 :
174 : /*
175 : * Verify that the Const is a query_int, else return a default estimate.
176 : * (This could only fail if someone attached this estimator to the wrong
177 : * operator.)
178 : */
179 98 : if (((Const *) other)->consttype !=
180 98 : get_function_sibling_type(fcinfo->flinfo->fn_oid, "query_int"))
181 : {
182 0 : ReleaseVariableStats(vardata);
183 0 : PG_RETURN_FLOAT8(DEFAULT_EQ_SEL);
184 : }
185 :
186 98 : query = DatumGetQueryTypeP(((Const *) other)->constvalue);
187 :
188 : /* Empty query matches nothing */
189 98 : if (query->size == 0)
190 : {
191 0 : ReleaseVariableStats(vardata);
192 0 : PG_RETURN_FLOAT8(0.0);
193 : }
194 :
195 : /*
196 : * Get the statistics for the intarray column.
197 : *
198 : * We're interested in the Most-Common-Elements list, and the NULL
199 : * fraction.
200 : */
201 98 : if (HeapTupleIsValid(vardata.statsTuple))
202 : {
203 : Form_pg_statistic stats;
204 :
205 86 : stats = (Form_pg_statistic) GETSTRUCT(vardata.statsTuple);
206 86 : nullfrac = stats->stanullfrac;
207 :
208 : /*
209 : * For an int4 array, the default array type analyze function will
210 : * collect a Most Common Elements list, which is an array of int4s.
211 : */
212 86 : if (get_attstatsslot(&sslot, vardata.statsTuple,
213 : STATISTIC_KIND_MCELEM, InvalidOid,
214 : ATTSTATSSLOT_VALUES | ATTSTATSSLOT_NUMBERS))
215 : {
216 : Assert(sslot.valuetype == INT4OID);
217 :
218 : /*
219 : * There should be three more Numbers than Values, because the
220 : * last three (for intarray) cells are taken for minimal, maximal
221 : * and nulls frequency. Punt if not.
222 : */
223 86 : if (sslot.nnumbers == sslot.nvalues + 3)
224 : {
225 : /* Grab the minimal MCE frequency. */
226 86 : minfreq = sslot.numbers[sslot.nvalues];
227 :
228 86 : mcelems = sslot.values;
229 86 : mcefreqs = sslot.numbers;
230 86 : nmcelems = sslot.nvalues;
231 : }
232 : }
233 : }
234 : else
235 12 : memset(&sslot, 0, sizeof(sslot));
236 :
237 : /* Process the logical expression in the query, using the stats */
238 98 : selec = int_query_opr_selec(GETQUERY(query) + query->size - 1,
239 : mcelems, mcefreqs, nmcelems, minfreq);
240 :
241 : /* MCE stats count only non-null rows, so adjust for null rows. */
242 98 : selec *= (1.0 - nullfrac);
243 :
244 98 : free_attstatsslot(&sslot);
245 98 : ReleaseVariableStats(vardata);
246 :
247 98 : CLAMP_PROBABILITY(selec);
248 :
249 98 : PG_RETURN_FLOAT8((float8) selec);
250 : }
251 :
252 : /*
253 : * Estimate selectivity of single intquery operator
254 : */
255 : static Selectivity
256 434 : int_query_opr_selec(ITEM *item, Datum *mcelems, float4 *mcefreqs,
257 : int nmcelems, float4 minfreq)
258 : {
259 : Selectivity selec;
260 :
261 : /* since this function recurses, it could be driven to stack overflow */
262 434 : check_stack_depth();
263 :
264 434 : if (item->type == VAL)
265 : {
266 : Datum *searchres;
267 :
268 238 : if (mcelems == NULL)
269 28 : return (Selectivity) DEFAULT_EQ_SEL;
270 :
271 210 : searchres = (Datum *) bsearch(&item->val, mcelems, nmcelems,
272 : sizeof(Datum), compare_val_int4);
273 210 : if (searchres)
274 : {
275 : /*
276 : * The element is in MCELEM. Return precise selectivity (or at
277 : * least as precise as ANALYZE could find out).
278 : */
279 182 : selec = mcefreqs[searchres - mcelems];
280 : }
281 : else
282 : {
283 : /*
284 : * The element is not in MCELEM. Estimate its frequency as half
285 : * that of the least-frequent MCE. (We know it cannot be more
286 : * than minfreq, and it could be a great deal less. Half seems
287 : * like a good compromise.) For probably-historical reasons,
288 : * clamp to not more than DEFAULT_EQ_SEL.
289 : */
290 28 : selec = Min(DEFAULT_EQ_SEL, minfreq / 2);
291 : }
292 : }
293 196 : else if (item->type == OPR)
294 : {
295 : /* Current query node is an operator */
296 : Selectivity s1,
297 : s2;
298 :
299 196 : s1 = int_query_opr_selec(item - 1, mcelems, mcefreqs, nmcelems,
300 : minfreq);
301 196 : switch (item->val)
302 : {
303 56 : case (int32) '!':
304 56 : selec = 1.0 - s1;
305 56 : break;
306 :
307 84 : case (int32) '&':
308 84 : s2 = int_query_opr_selec(item + item->left, mcelems, mcefreqs,
309 : nmcelems, minfreq);
310 84 : selec = s1 * s2;
311 84 : break;
312 :
313 56 : case (int32) '|':
314 56 : s2 = int_query_opr_selec(item + item->left, mcelems, mcefreqs,
315 : nmcelems, minfreq);
316 56 : selec = s1 + s2 - s1 * s2;
317 56 : break;
318 :
319 0 : default:
320 0 : elog(ERROR, "unrecognized operator: %d", item->val);
321 : selec = 0; /* keep compiler quiet */
322 : break;
323 : }
324 : }
325 : else
326 : {
327 0 : elog(ERROR, "unrecognized int query item type: %u", item->type);
328 : selec = 0; /* keep compiler quiet */
329 : }
330 :
331 : /* Clamp intermediate results to stay sane despite roundoff error */
332 406 : CLAMP_PROBABILITY(selec);
333 :
334 406 : return selec;
335 : }
336 :
337 : /*
338 : * Comparison function for binary search in mcelem array.
339 : */
340 : static int
341 1494 : compare_val_int4(const void *a, const void *b)
342 : {
343 1494 : int32 key = *(const int32 *) a;
344 1494 : int32 value = DatumGetInt32(*(const Datum *) b);
345 :
346 1494 : if (key < value)
347 782 : return -1;
348 712 : else if (key > value)
349 530 : return 1;
350 : else
351 182 : return 0;
352 : }
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