Age Owner Branch data TLA Line data Source code
1 : : /*--------------------------------------------------------------------------
2 : : *
3 : : * test_predtest.c
4 : : * Test correctness of optimizer's predicate proof logic.
5 : : *
6 : : * Copyright (c) 2018-2024, PostgreSQL Global Development Group
7 : : *
8 : : * IDENTIFICATION
9 : : * src/test/modules/test_predtest/test_predtest.c
10 : : *
11 : : * -------------------------------------------------------------------------
12 : : */
13 : :
14 : : #include "postgres.h"
15 : :
16 : : #include "access/htup_details.h"
17 : : #include "catalog/pg_type.h"
18 : : #include "executor/spi.h"
19 : : #include "funcapi.h"
20 : : #include "nodes/makefuncs.h"
21 : : #include "optimizer/optimizer.h"
22 : : #include "utils/builtins.h"
23 : :
2229 tgl@sss.pgh.pa.us 24 :CBC 1 : PG_MODULE_MAGIC;
25 : :
26 : : /*
27 : : * test_predtest(query text) returns record
28 : : */
29 : 2 : PG_FUNCTION_INFO_V1(test_predtest);
30 : :
31 : : Datum
32 : 74 : test_predtest(PG_FUNCTION_ARGS)
33 : : {
34 : 74 : text *txt = PG_GETARG_TEXT_PP(0);
35 : 74 : char *query_string = text_to_cstring(txt);
36 : : SPIPlanPtr spiplan;
37 : : int spirc;
38 : : TupleDesc tupdesc;
39 : : bool s_i_holds,
40 : : w_i_holds,
41 : : s_r_holds,
42 : : w_r_holds;
43 : : CachedPlan *cplan;
44 : : PlannedStmt *stmt;
45 : : Plan *plan;
46 : : Expr *clause1;
47 : : Expr *clause2;
48 : : bool strong_implied_by,
49 : : weak_implied_by,
50 : : strong_refuted_by,
51 : : weak_refuted_by;
52 : : Datum values[8];
638 peter@eisentraut.org 53 : 74 : bool nulls[8] = {0};
54 : : int i;
55 : :
56 : : /* We use SPI to parse, plan, and execute the test query */
2229 tgl@sss.pgh.pa.us 57 [ - + ]: 74 : if (SPI_connect() != SPI_OK_CONNECT)
2229 tgl@sss.pgh.pa.us 58 [ # # ]:UBC 0 : elog(ERROR, "SPI_connect failed");
59 : :
60 : : /*
61 : : * First, plan and execute the query, and inspect the results. To the
62 : : * extent that the query fully exercises the two expressions, this
63 : : * provides an experimental indication of whether implication or
64 : : * refutation holds.
65 : : */
2229 tgl@sss.pgh.pa.us 66 :CBC 74 : spiplan = SPI_prepare(query_string, 0, NULL);
67 [ - + ]: 74 : if (spiplan == NULL)
2229 tgl@sss.pgh.pa.us 68 [ # # ]:UBC 0 : elog(ERROR, "SPI_prepare failed for \"%s\"", query_string);
69 : :
2229 tgl@sss.pgh.pa.us 70 :CBC 74 : spirc = SPI_execute_plan(spiplan, NULL, NULL, true, 0);
71 [ - + ]: 74 : if (spirc != SPI_OK_SELECT)
2229 tgl@sss.pgh.pa.us 72 [ # # ]:UBC 0 : elog(ERROR, "failed to execute \"%s\"", query_string);
2229 tgl@sss.pgh.pa.us 73 :CBC 74 : tupdesc = SPI_tuptable->tupdesc;
74 [ + - ]: 74 : if (tupdesc->natts != 2 ||
75 [ + - ]: 74 : TupleDescAttr(tupdesc, 0)->atttypid != BOOLOID ||
76 [ - + ]: 74 : TupleDescAttr(tupdesc, 1)->atttypid != BOOLOID)
2229 tgl@sss.pgh.pa.us 77 [ # # ]:UBC 0 : elog(ERROR, "query must yield two boolean columns");
78 : :
2229 tgl@sss.pgh.pa.us 79 :CBC 74 : s_i_holds = w_i_holds = s_r_holds = w_r_holds = true;
80 [ + + ]: 7550 : for (i = 0; i < SPI_processed; i++)
81 : : {
82 : 7476 : HeapTuple tup = SPI_tuptable->vals[i];
83 : : Datum dat;
84 : : bool isnull;
85 : : char c1,
86 : : c2;
87 : :
88 : : /* Extract column values in a 3-way representation */
89 : 7476 : dat = SPI_getbinval(tup, tupdesc, 1, &isnull);
90 [ + + ]: 7476 : if (isnull)
91 : 1154 : c1 = 'n';
92 [ + + ]: 6322 : else if (DatumGetBool(dat))
93 : 3126 : c1 = 't';
94 : : else
95 : 3196 : c1 = 'f';
96 : :
97 : 7476 : dat = SPI_getbinval(tup, tupdesc, 2, &isnull);
98 [ + + ]: 7476 : if (isnull)
99 : 1192 : c2 = 'n';
100 [ + + ]: 6284 : else if (DatumGetBool(dat))
101 : 2620 : c2 = 't';
102 : : else
103 : 3664 : c2 = 'f';
104 : :
105 : : /* Check for violations of various proof conditions */
106 : :
107 : : /* strong implication: truth of c2 implies truth of c1 */
108 [ + + + + ]: 7476 : if (c2 == 't' && c1 != 't')
109 : 1366 : s_i_holds = false;
110 : : /* weak implication: non-falsity of c2 implies non-falsity of c1 */
111 [ + + + + ]: 7476 : if (c2 != 'f' && c1 == 'f')
112 : 1420 : w_i_holds = false;
113 : : /* strong refutation: truth of c2 implies falsity of c1 */
114 [ + + + + ]: 7476 : if (c2 == 't' && c1 != 'f')
115 : 1452 : s_r_holds = false;
116 : : /* weak refutation: truth of c2 implies non-truth of c1 */
117 [ + + + + ]: 7476 : if (c2 == 't' && c1 == 't')
118 : 1254 : w_r_holds = false;
119 : : }
120 : :
121 : : /*
122 : : * Strong refutation implies weak refutation, so we should never observe
123 : : * s_r_holds = true with w_r_holds = false.
124 : : *
125 : : * We can't make a comparable assertion for implication since moving from
126 : : * strong to weak implication expands the allowed values of "A" from true
127 : : * to either true or NULL.
128 : : *
129 : : * If this fails it constitutes a bug not with the proofs but with either
130 : : * this test module or a more core part of expression evaluation since we
131 : : * are validating the logical correctness of the observed result rather
132 : : * than the proof.
133 : : */
20 tgl@sss.pgh.pa.us 134 [ + + - + ]:GNC 74 : if (s_r_holds && !w_r_holds)
20 tgl@sss.pgh.pa.us 135 [ # # ]:UNC 0 : elog(WARNING, "s_r_holds was true; w_r_holds must not be false");
136 : :
137 : : /*
138 : : * Now, dig the clause querytrees out of the plan, and see what predtest.c
139 : : * does with them.
140 : : */
2229 tgl@sss.pgh.pa.us 141 :CBC 74 : cplan = SPI_plan_get_cached_plan(spiplan);
142 : :
143 [ - + ]: 74 : if (list_length(cplan->stmt_list) != 1)
2229 tgl@sss.pgh.pa.us 144 [ # # ]:UBC 0 : elog(ERROR, "failed to decipher query plan");
2229 tgl@sss.pgh.pa.us 145 :CBC 74 : stmt = linitial_node(PlannedStmt, cplan->stmt_list);
146 [ - + ]: 74 : if (stmt->commandType != CMD_SELECT)
2229 tgl@sss.pgh.pa.us 147 [ # # ]:UBC 0 : elog(ERROR, "failed to decipher query plan");
2229 tgl@sss.pgh.pa.us 148 :CBC 74 : plan = stmt->planTree;
149 [ - + ]: 74 : Assert(list_length(plan->targetlist) >= 2);
1000 peter@eisentraut.org 150 : 74 : clause1 = linitial_node(TargetEntry, plan->targetlist)->expr;
151 : 74 : clause2 = lsecond_node(TargetEntry, plan->targetlist)->expr;
152 : :
153 : : /*
154 : : * Because the clauses are in the SELECT list, preprocess_expression did
155 : : * not pass them through canonicalize_qual nor make_ands_implicit.
156 : : *
157 : : * We can't do canonicalize_qual here, since it's unclear whether the
158 : : * expressions ought to be treated as WHERE or CHECK clauses. Fortunately,
159 : : * useful test expressions wouldn't be affected by those transformations
160 : : * anyway. We should do make_ands_implicit, though.
161 : : *
162 : : * Another way in which this does not exactly duplicate the normal usage
163 : : * of the proof functions is that they are often given qual clauses
164 : : * containing RestrictInfo nodes. But since predtest.c just looks through
165 : : * those anyway, it seems OK to not worry about that point.
166 : : */
2229 tgl@sss.pgh.pa.us 167 : 74 : clause1 = (Expr *) make_ands_implicit(clause1);
168 : 74 : clause2 = (Expr *) make_ands_implicit(clause2);
169 : :
170 : 74 : strong_implied_by = predicate_implied_by((List *) clause1,
171 : : (List *) clause2,
172 : : false);
173 : :
174 : 74 : weak_implied_by = predicate_implied_by((List *) clause1,
175 : : (List *) clause2,
176 : : true);
177 : :
178 : 74 : strong_refuted_by = predicate_refuted_by((List *) clause1,
179 : : (List *) clause2,
180 : : false);
181 : :
182 : 74 : weak_refuted_by = predicate_refuted_by((List *) clause1,
183 : : (List *) clause2,
184 : : true);
185 : :
186 : : /*
187 : : * Issue warning if any proof is demonstrably incorrect.
188 : : */
189 [ + + - + ]: 74 : if (strong_implied_by && !s_i_holds)
2229 tgl@sss.pgh.pa.us 190 [ # # ]:UBC 0 : elog(WARNING, "strong_implied_by result is incorrect");
2229 tgl@sss.pgh.pa.us 191 [ + + - + ]:CBC 74 : if (weak_implied_by && !w_i_holds)
2229 tgl@sss.pgh.pa.us 192 [ # # ]:UBC 0 : elog(WARNING, "weak_implied_by result is incorrect");
2229 tgl@sss.pgh.pa.us 193 [ + + - + ]:CBC 74 : if (strong_refuted_by && !s_r_holds)
2229 tgl@sss.pgh.pa.us 194 [ # # ]:UBC 0 : elog(WARNING, "strong_refuted_by result is incorrect");
2229 tgl@sss.pgh.pa.us 195 [ + + - + ]:CBC 74 : if (weak_refuted_by && !w_r_holds)
2229 tgl@sss.pgh.pa.us 196 [ # # ]:UBC 0 : elog(WARNING, "weak_refuted_by result is incorrect");
197 : :
198 : : /*
199 : : * As with our earlier check of the logical consistency of whether strong
200 : : * and weak refutation hold, we ought never prove strong refutation
201 : : * without also proving weak refutation.
202 : : *
203 : : * Also as earlier we cannot make the same guarantee about implication
204 : : * proofs.
205 : : *
206 : : * A warning here suggests a bug in the proof code.
207 : : */
20 tgl@sss.pgh.pa.us 208 [ + + - + ]:GNC 74 : if (strong_refuted_by && !weak_refuted_by)
20 tgl@sss.pgh.pa.us 209 [ # # ]:UNC 0 : elog(WARNING, "strong_refuted_by was proven; weak_refuted_by should also be proven");
210 : :
211 : : /*
212 : : * Clean up and return a record of the results.
213 : : */
2229 tgl@sss.pgh.pa.us 214 [ - + ]:CBC 74 : if (SPI_finish() != SPI_OK_FINISH)
2229 tgl@sss.pgh.pa.us 215 [ # # ]:UBC 0 : elog(ERROR, "SPI_finish failed");
216 : :
1972 andres@anarazel.de 217 :CBC 74 : tupdesc = CreateTemplateTupleDesc(8);
2229 tgl@sss.pgh.pa.us 218 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 1,
219 : : "strong_implied_by", BOOLOID, -1, 0);
220 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 2,
221 : : "weak_implied_by", BOOLOID, -1, 0);
222 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 3,
223 : : "strong_refuted_by", BOOLOID, -1, 0);
224 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 4,
225 : : "weak_refuted_by", BOOLOID, -1, 0);
226 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 5,
227 : : "s_i_holds", BOOLOID, -1, 0);
228 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 6,
229 : : "w_i_holds", BOOLOID, -1, 0);
230 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 7,
231 : : "s_r_holds", BOOLOID, -1, 0);
232 : 74 : TupleDescInitEntry(tupdesc, (AttrNumber) 8,
233 : : "w_r_holds", BOOLOID, -1, 0);
234 : 74 : tupdesc = BlessTupleDesc(tupdesc);
235 : :
236 : 74 : values[0] = BoolGetDatum(strong_implied_by);
237 : 74 : values[1] = BoolGetDatum(weak_implied_by);
238 : 74 : values[2] = BoolGetDatum(strong_refuted_by);
239 : 74 : values[3] = BoolGetDatum(weak_refuted_by);
240 : 74 : values[4] = BoolGetDatum(s_i_holds);
241 : 74 : values[5] = BoolGetDatum(w_i_holds);
242 : 74 : values[6] = BoolGetDatum(s_r_holds);
243 : 74 : values[7] = BoolGetDatum(w_r_holds);
244 : :
245 : 74 : PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
246 : : }
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