Line data Source code
1 : /*
2 : * SPDX-License-Identifier: MPL-2.0
3 : *
4 : * This Source Code Form is subject to the terms of the Mozilla Public
5 : * License, v. 2.0. If a copy of the MPL was not distributed with this
6 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
7 : *
8 : * Copyright 2024 MonetDB Foundation;
9 : * Copyright August 2008 - 2023 MonetDB B.V.;
10 : * Copyright 1997 - July 2008 CWI.
11 : */
12 :
13 : #include "monetdb_config.h"
14 : #include "opt_commonTerms.h"
15 : #include "mal_exception.h"
16 : /*
17 : * Caveat. A lot of time was lost due to constants that are indistinguisable
18 : * at the surface level. It requires the constant optimizer to be ran first.
19 : */
20 :
21 : /* The key for finding common terms is that they share variables.
22 : * Therefore we skip all constants, except for a constant only situation.
23 : */
24 :
25 : /*
26 : * Speed up simple insert operations by skipping the common terms.
27 : */
28 :
29 : static inline bool __attribute__((__pure__))
30 219428 : isProjectConst(const InstrRecord *p)
31 : {
32 219428 : return (getModuleId(p) == algebraRef && getFunctionId(p) == projectRef);
33 : }
34 :
35 : static int __attribute__((__pure__))
36 11786084 : hashInstruction(const MalBlkRecord *mb, const InstrRecord *p)
37 : {
38 11786084 : int i;
39 30723003 : for (i = p->argc - 1; i >= p->retc; i--)
40 30408981 : if (!isVarConstant(mb, getArg(p, i)))
41 11472062 : return getArg(p, i);
42 314022 : if (isVarConstant(mb, getArg(p, p->retc)))
43 314022 : return p->retc;
44 : return -1;
45 : }
46 :
47 : str
48 477403 : OPTcommonTermsImplementation(Client cntxt, MalBlkPtr mb, MalStkPtr stk,
49 : InstrPtr pci)
50 : {
51 477403 : int i, j, k, barrier = 0, bailout = 0;
52 477403 : InstrPtr p, q;
53 477403 : int actions = 0;
54 477403 : int limit, slimit;
55 477403 : int duplicate;
56 477403 : int *alias = NULL;
57 477403 : int *hash = NULL, h;
58 477403 : int *list = NULL;
59 477403 : str msg = MAL_SUCCEED;
60 :
61 477403 : InstrPtr *old = NULL;
62 :
63 : /* catch simple insert operations */
64 477403 : if (isSimpleSQL(mb)) {
65 272871 : goto wrapup;
66 : }
67 :
68 204574 : (void) cntxt;
69 204574 : (void) stk;
70 204574 : alias = (int *) GDKzalloc(sizeof(int) * mb->vtop);
71 204595 : list = (int *) GDKzalloc(sizeof(int) * mb->stop);
72 204585 : hash = (int *) GDKzalloc(sizeof(int) * mb->vtop);
73 204596 : if (alias == NULL || list == NULL || hash == NULL) {
74 0 : msg = createException(MAL, "optimizer.commonTerms",
75 : SQLSTATE(HY013) MAL_MALLOC_FAIL);
76 0 : goto wrapup;
77 : }
78 :
79 204596 : old = mb->stmt;
80 204596 : limit = mb->stop;
81 204596 : slimit = mb->ssize;
82 204596 : if (newMalBlkStmt(mb, mb->ssize) < 0) {
83 0 : msg = createException(MAL, "optimizer.commonTerms",
84 : SQLSTATE(HY013) MAL_MALLOC_FAIL);
85 0 : old = NULL;
86 0 : goto wrapup;
87 : }
88 :
89 14684225 : for (i = 0; mb->errors == NULL && i < limit; i++) {
90 14684225 : p = old[i];
91 14684225 : duplicate = 0;
92 :
93 80745190 : for (k = 0; k < p->argc; k++)
94 66060965 : if (alias[getArg(p, k)])
95 275346 : getArg(p, k) = alias[getArg(p, k)];
96 :
97 14684225 : if (p->token == ENDsymbol) {
98 204531 : pushInstruction(mb, p);
99 204559 : old[i] = NULL;
100 204559 : break;
101 : }
102 : /*
103 : * Any barrier block signals the end of this optimizer,
104 : * because the impact of the block can affect the common code eliminated.
105 : */
106 28959388 : barrier |= (p->barrier == BARRIERsymbol || p->barrier == CATCHsymbol
107 14479694 : || p->barrier == RETURNsymbol);
108 : /*
109 : * Also block further optimization when you have seen an assert().
110 : * This works particularly for SQL, because it is not easy to track
111 : * the BAT identifier aliases to look for updates. The sql.assert
112 : * at least tells us that an update is planned.
113 : * Like all optimizer decisions, it is safe to stop.
114 : */
115 14479694 : barrier |= getFunctionId(p) == assertRef;
116 14479694 : if (barrier || p->token == ASSIGNsymbol) {
117 241320 : TRC_DEBUG(MAL_OPTIMIZER, "Skipped[%d]: %d %d\n", i, barrier,
118 : p->retc == p->argc);
119 241320 : pushInstruction(mb, p);
120 241325 : old[i] = NULL;
121 241325 : continue;
122 : }
123 :
124 : /* when we enter a barrier block, we should ditch all previous instructions from consideration */
125 14238374 : if (p->barrier == BARRIERsymbol || p->barrier == CATCHsymbol
126 14238374 : || p->barrier == RETURNsymbol) {
127 0 : memset(list, 0, sizeof(int) * mb->stop);
128 0 : memset(hash, 0, sizeof(int) * mb->vtop);
129 : }
130 : /* side-effect producing operators can never be replaced */
131 : /* the same holds for function calls without an argument, it is
132 : * unclear where the results comes from (e.g. clock()) */
133 14238374 : if (mayhaveSideEffects(cntxt, mb, p, TRUE) || p->argc == p->retc) {
134 1664270 : TRC_DEBUG(MAL_OPTIMIZER, "Skipped[%d] side-effect: %d\n", i,
135 : p->retc == p->argc);
136 1664270 : pushInstruction(mb, p);
137 1664255 : old[i] = NULL;
138 1664255 : continue;
139 : }
140 : /* simple SQL bind operations need not be merged, they are cheap
141 : * and/or can be duplicated eliminated elsewhere cheaper */
142 12575046 : if (getModuleId(p) == sqlRef && (getFunctionId(p) != tidRef && getFunctionId(p) != bindRef)) {
143 789281 : pushInstruction(mb, p);
144 789281 : old[i] = NULL;
145 789281 : continue;
146 : }
147 :
148 : /* from here we have a candidate to look for a match */
149 :
150 11785765 : h = hashInstruction(mb, p);
151 :
152 11785765 : TRC_DEBUG(MAL_OPTIMIZER, "Candidate[%d] look at list[%d] => %d\n", i, h,
153 : hash[h]);
154 11785765 : traceInstruction(MAL_OPTIMIZER, mb, 0, p, LIST_MAL_ALL);
155 :
156 11785761 : if (h < 0) {
157 0 : pushInstruction(mb, p);
158 0 : old[i] = NULL;
159 0 : continue;
160 : }
161 :
162 11785761 : bailout = 1024; // don't run over long collision list
163 : /* Look into the hash structure for matching instructions */
164 96481026 : for (j = hash[h]; j > 0 && bailout-- > 0; j = list[j]) {
165 84898512 : if ((q = getInstrPtr(mb, j))
166 84898512 : && getFunctionId(q) == getFunctionId(p)
167 67105739 : && getModuleId(q) == getModuleId(p)) {
168 67110811 : TRC_DEBUG(MAL_OPTIMIZER,
169 : "Candidate[%d->%d] %d %d :%d %d %d=%d %d %d %d\n", j,
170 : list[j], hasSameSignature(mb, p, q),
171 : hasSameArguments(mb, p, q), q->token != ASSIGNsymbol,
172 : list[getArg(q, q->argc - 1)], i, !hasCommonResults(p,
173 : q),
174 : !isUnsafeFunction(q), !isUpdateInstruction(q),
175 : isLinearFlow(q));
176 67110811 : traceInstruction(MAL_OPTIMIZER, mb, 0, q, LIST_MAL_ALL);
177 :
178 : /*
179 : * Simple assignments are not replaced either. They should be
180 : * handled by the alias removal part. All arguments should
181 : * be assigned their value before instruction p.
182 : */
183 67116144 : if (hasSameArguments(mb, p, q)
184 219446 : && hasSameSignature(mb, p, q)
185 219428 : && !hasCommonResults(p, q)
186 219428 : && !isUnsafeFunction(q)
187 219428 : && !isUpdateInstruction(q)
188 219428 : && !isProjectConst(q) && /* disable project(x,val), as its used for the result of case statements */
189 201561 : isLinearFlow(q)) {
190 201561 : if (safetyBarrier(p, q)) {
191 0 : TRC_DEBUG(MAL_OPTIMIZER, "Safety barrier reached\n");
192 : break;
193 : }
194 201561 : duplicate = 1;
195 201561 : clrFunction(p);
196 201561 : p->argc = p->retc;
197 411819 : for (k = 0; k < q->retc; k++) {
198 210258 : alias[getArg(p, k)] = getArg(q, k);
199 : /* we know the arguments fit so the instruction can safely be patched */
200 210258 : p = pushArgument(mb, p, getArg(q, k));
201 : }
202 :
203 201561 : TRC_DEBUG(MAL_OPTIMIZER, "Modified expression %d -> %d ",
204 : getArg(p, 0), getArg(p, 1));
205 201561 : traceInstruction(MAL_OPTIMIZER, mb, 0, p, LIST_MAL_ALL);
206 :
207 201561 : actions++;
208 201561 : break; /* end of search */
209 : }
210 17787701 : } else if (isUpdateInstruction(p)) {
211 0 : TRC_DEBUG(MAL_OPTIMIZER, "Skipped: %d %d\n",
212 : mayhaveSideEffects(cntxt, mb, q, TRUE),
213 : isUpdateInstruction(p));
214 0 : traceInstruction(MAL_OPTIMIZER, mb, 0, q, LIST_MAL_ALL);
215 : }
216 : }
217 :
218 11784075 : if (duplicate) {
219 201561 : pushInstruction(mb, p);
220 201561 : old[i] = NULL;
221 201561 : continue;
222 : }
223 : /* update the hash structure with another candidate for re-use */
224 11582514 : TRC_DEBUG(MAL_OPTIMIZER,
225 : "Update hash[%d] - look at arg '%d' hash '%d' list '%d'\n", i,
226 : getArg(p, p->argc - 1), h, hash[h]);
227 11582514 : traceInstruction(MAL_OPTIMIZER, mb, 0, p, LIST_MAL_ALL);
228 :
229 11582922 : if (!mayhaveSideEffects(cntxt, mb, p, TRUE) && p->argc != p->retc
230 23166635 : && isLinearFlow(p) && !isUnsafeFunction(p)
231 11583322 : && !isUpdateInstruction(p)) {
232 11583301 : list[i] = hash[h];
233 11583301 : hash[h] = i;
234 11583301 : pushInstruction(mb, p);
235 11583502 : old[i] = NULL;
236 : }
237 : }
238 47055417 : for (; i < slimit; i++)
239 46850827 : if (old[i])
240 5202519 : pushInstruction(mb, old[i]);
241 : /* Defense line against incorrect plans */
242 204590 : if (actions > 0) {
243 8654 : msg = chkTypes(cntxt->usermodule, mb, FALSE);
244 8654 : if (!msg)
245 8654 : msg = chkFlow(mb);
246 8654 : if (!msg)
247 8654 : msg = chkDeclarations(mb);
248 : }
249 195936 : wrapup:
250 : /* keep actions taken as a fake argument */
251 477461 : (void) pushInt(mb, pci, actions);
252 :
253 477444 : if (alias)
254 204573 : GDKfree(alias);
255 477467 : if (list)
256 204596 : GDKfree(list);
257 477463 : if (hash)
258 204592 : GDKfree(hash);
259 477446 : if (old)
260 204575 : GDKfree(old);
261 477465 : return msg;
262 : }
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