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 161721 : isProjectConst(const InstrRecord *p)
31 : {
32 161721 : return (getModuleId(p) == algebraRef && getFunctionId(p) == projectRef);
33 : }
34 :
35 : static int __attribute__((__pure__))
36 7193399 : hashInstruction(const MalBlkRecord *mb, const InstrRecord *p)
37 : {
38 7193399 : int i;
39 19244837 : for (i = p->argc - 1; i >= p->retc; i--)
40 18927420 : if (!isVarConstant(mb, getArg(p, i)))
41 6875982 : return getArg(p, i);
42 317417 : if (isVarConstant(mb, getArg(p, p->retc)))
43 317417 : return p->retc;
44 : return -1;
45 : }
46 :
47 : str
48 467672 : OPTcommonTermsImplementation(Client cntxt, MalBlkPtr mb, MalStkPtr stk,
49 : InstrPtr pci)
50 : {
51 467672 : int i, j, k, barrier = 0, bailout = 0;
52 467672 : InstrPtr p, q;
53 467672 : int actions = 0;
54 467672 : int limit, slimit;
55 467672 : int duplicate;
56 467672 : int *alias = NULL;
57 467672 : int *hash = NULL, h;
58 467672 : int *list = NULL;
59 467672 : str msg = MAL_SUCCEED;
60 :
61 467672 : InstrPtr *old = NULL;
62 :
63 : /* catch simple insert operations */
64 467672 : if (isSimpleSQL(mb)) {
65 266907 : goto wrapup;
66 : }
67 :
68 200765 : (void) cntxt;
69 200765 : (void) stk;
70 200765 : alias = (int *) GDKzalloc(sizeof(int) * mb->vtop);
71 200764 : list = (int *) GDKzalloc(sizeof(int) * mb->stop);
72 200764 : hash = (int *) GDKzalloc(sizeof(int) * mb->vtop);
73 200763 : 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 200763 : old = mb->stmt;
80 200763 : limit = mb->stop;
81 200763 : slimit = mb->ssize;
82 200763 : 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 9728451 : for (i = 0; mb->errors == NULL && i < limit; i++) {
90 9728451 : p = old[i];
91 9728451 : duplicate = 0;
92 :
93 52817512 : for (k = 0; k < p->argc; k++)
94 43089061 : if (alias[getArg(p, k)])
95 193796 : getArg(p, k) = alias[getArg(p, k)];
96 :
97 9728451 : if (p->token == ENDsymbol) {
98 200759 : pushInstruction(mb, p);
99 200756 : old[i] = NULL;
100 200756 : 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 19055384 : barrier |= (p->barrier == BARRIERsymbol || p->barrier == CATCHsymbol
107 9527692 : || 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 9527692 : barrier |= getFunctionId(p) == assertRef;
116 9527692 : if (barrier || p->token == ASSIGNsymbol) {
117 244072 : TRC_DEBUG(MAL_OPTIMIZER, "Skipped[%d]: %d %d\n", i, barrier,
118 : p->retc == p->argc);
119 244072 : pushInstruction(mb, p);
120 244072 : old[i] = NULL;
121 244072 : continue;
122 : }
123 :
124 : /* when we enter a barrier block, we should ditch all previous instructions from consideration */
125 9283620 : if (p->barrier == BARRIERsymbol || p->barrier == CATCHsymbol
126 9283620 : || 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 9283620 : if (mayhaveSideEffects(cntxt, mb, p, TRUE) || p->argc == p->retc) {
134 1591977 : TRC_DEBUG(MAL_OPTIMIZER, "Skipped[%d] side-effect: %d\n", i,
135 : p->retc == p->argc);
136 1591977 : pushInstruction(mb, p);
137 1591959 : old[i] = NULL;
138 1591959 : continue;
139 : }
140 : /* simple SQL bind operations need not be merged, they are cheap
141 : * and/or can be duplicated eliminated elsewhere cheaper */
142 7691836 : if (getModuleId(p) == sqlRef && (getFunctionId(p) != tidRef && getFunctionId(p) != bindRef)) {
143 498599 : pushInstruction(mb, p);
144 498599 : old[i] = NULL;
145 498599 : continue;
146 : }
147 :
148 : /* from here we have a candidate to look for a match */
149 :
150 7193237 : h = hashInstruction(mb, p);
151 :
152 7193237 : TRC_DEBUG(MAL_OPTIMIZER, "Candidate[%d] look at list[%d] => %d\n", i, h,
153 : hash[h]);
154 7193237 : traceInstruction(MAL_OPTIMIZER, mb, 0, p, LIST_MAL_ALL);
155 :
156 7193246 : if (h < 0) {
157 0 : pushInstruction(mb, p);
158 0 : old[i] = NULL;
159 0 : continue;
160 : }
161 :
162 7193246 : bailout = 1024; // don't run over long collision list
163 : /* Look into the hash structure for matching instructions */
164 42053920 : for (j = hash[h]; j > 0 && bailout-- > 0; j = list[j]) {
165 35008897 : if ((q = getInstrPtr(mb, j))
166 35008897 : && getFunctionId(q) == getFunctionId(p)
167 25855011 : && getModuleId(q) == getModuleId(p)) {
168 25854996 : 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 25854996 : 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 25854738 : if (hasSameArguments(mb, p, q)
184 161721 : && hasSameSignature(mb, p, q)
185 161721 : && !hasCommonResults(p, q)
186 161721 : && !isUnsafeFunction(q)
187 161721 : && !isUpdateInstruction(q)
188 161721 : && !isProjectConst(q) && /* disable project(x,val), as its used for the result of case statements */
189 148253 : isLinearFlow(q)) {
190 148253 : if (safetyBarrier(p, q)) {
191 0 : TRC_DEBUG(MAL_OPTIMIZER, "Safety barrier reached\n");
192 : break;
193 : }
194 148253 : duplicate = 1;
195 148253 : clrFunction(p);
196 148253 : p->argc = p->retc;
197 304264 : for (k = 0; k < q->retc; k++) {
198 156011 : alias[getArg(p, k)] = getArg(q, k);
199 : /* we know the arguments fit so the instruction can safely be patched */
200 156011 : p = pushArgument(mb, p, getArg(q, k));
201 : }
202 :
203 148253 : TRC_DEBUG(MAL_OPTIMIZER, "Modified expression %d -> %d ",
204 : getArg(p, 0), getArg(p, 1));
205 148253 : traceInstruction(MAL_OPTIMIZER, mb, 0, p, LIST_MAL_ALL);
206 :
207 148253 : actions++;
208 148253 : break; /* end of search */
209 : }
210 9153901 : } 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 7193276 : if (duplicate) {
219 148253 : pushInstruction(mb, p);
220 148253 : old[i] = NULL;
221 148253 : continue;
222 : }
223 : /* update the hash structure with another candidate for re-use */
224 7045023 : 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 7045023 : traceInstruction(MAL_OPTIMIZER, mb, 0, p, LIST_MAL_ALL);
228 :
229 7044992 : if (!mayhaveSideEffects(cntxt, mb, p, TRUE) && p->argc != p->retc
230 14089925 : && isLinearFlow(p) && !isUnsafeFunction(p)
231 7044958 : && !isUpdateInstruction(p)) {
232 7044843 : list[i] = hash[h];
233 7044843 : hash[h] = i;
234 7044843 : pushInstruction(mb, p);
235 7044805 : old[i] = NULL;
236 : }
237 : }
238 46573634 : for (; i < slimit; i++)
239 46372869 : if (old[i])
240 5090565 : pushInstruction(mb, old[i]);
241 : /* Defense line against incorrect plans */
242 200765 : if (actions > 0) {
243 9935 : msg = chkTypes(cntxt->usermodule, mb, FALSE);
244 9935 : if (!msg)
245 9935 : msg = chkFlow(mb);
246 9935 : if (!msg)
247 9935 : msg = chkDeclarations(mb);
248 : }
249 190830 : wrapup:
250 : /* keep actions taken as a fake argument */
251 467672 : (void) pushInt(mb, pci, actions);
252 :
253 467672 : if (alias)
254 200765 : GDKfree(alias);
255 467672 : if (list)
256 200765 : GDKfree(list);
257 467672 : if (hash)
258 200765 : GDKfree(hash);
259 467672 : if (old)
260 200765 : GDKfree(old);
261 467672 : return msg;
262 : }
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