xref: /illumos-gate/usr/src/cmd/sendmail/db/db/db_join.c (revision 2a8bcb4e)
1 /*-
2  * See the file LICENSE for redistribution information.
3  *
4  * Copyright (c) 1998
5  *	Sleepycat Software.  All rights reserved.
6  */
7 
8 #include "config.h"
9 
10 #ifndef lint
11 static const char sccsid[] = "@(#)db_join.c	10.10 (Sleepycat) 10/9/98";
12 #endif /* not lint */
13 
14 #ifndef NO_SYSTEM_INCLUDES
15 #include <sys/types.h>
16 
17 #include <errno.h>
18 #include <string.h>
19 #endif
20 
21 #include "db_int.h"
22 #include "db_page.h"
23 #include "db_join.h"
24 #include "db_am.h"
25 #include "common_ext.h"
26 
27 static int __db_join_close __P((DBC *));
28 static int __db_join_del __P((DBC *, u_int32_t));
29 static int __db_join_get __P((DBC *, DBT *, DBT *, u_int32_t));
30 static int __db_join_put __P((DBC *, DBT *, DBT *, u_int32_t));
31 
32 /*
33  * This is the duplicate-assisted join functionality.  Right now we're
34  * going to write it such that we return one item at a time, although
35  * I think we may need to optimize it to return them all at once.
36  * It should be easier to get it working this way, and I believe that
37  * changing it should be fairly straightforward.
38  *
39  * XXX
40  * Right now we do not maintain the number of duplicates so we do
41  * not optimize the join.  If the caller does, then best performance
42  * will be achieved by putting the cursor with the smallest cardinality
43  * first.
44  *
45  * The first cursor moves sequentially through the duplicate set while
46  * the others search explicitly for the duplicate in question.
47  *
48  */
49 
50 /*
51  * __db_join --
52  *	This is the interface to the duplicate-assisted join functionality.
53  * In the same way that cursors mark a position in a database, a cursor
54  * can mark a position in a join.  While most cursors are created by the
55  * cursor method of a DB, join cursors are created through an explicit
56  * call to DB->join.
57  *
58  * The curslist is an array of existing, intialized cursors and primary
59  * is the DB of the primary file.  The data item that joins all the
60  * cursors in the curslist is used as the key into the primary and that
61  * key and data are returned.  When no more items are left in the join
62  * set, the  c_next operation off the join cursor will return DB_NOTFOUND.
63  *
64  * PUBLIC: int __db_join __P((DB *, DBC **, u_int32_t, DBC **));
65  */
66 int
__db_join(primary,curslist,flags,dbcp)67 __db_join(primary, curslist, flags, dbcp)
68 	DB *primary;
69 	DBC **curslist, **dbcp;
70 	u_int32_t flags;
71 {
72 	DBC *dbc;
73 	JOIN_CURSOR *jc;
74 	int i, ret;
75 
76 	DB_PANIC_CHECK(primary);
77 
78 	if ((ret = __db_joinchk(primary, flags)) != 0)
79 		return (ret);
80 
81 	if (curslist == NULL || curslist[0] == NULL)
82 		return (EINVAL);
83 
84 	dbc = NULL;
85 	jc = NULL;
86 
87 	if ((ret = __os_calloc(1, sizeof(DBC), &dbc)) != 0)
88 		goto err;
89 
90 	if ((ret = __os_calloc(1, sizeof(JOIN_CURSOR), &jc)) != 0)
91 		goto err;
92 
93 	if ((ret = __os_malloc(256, NULL, &jc->j_key.data)) != 0)
94 		goto err;
95 	jc->j_key.ulen = 256;
96 	F_SET(&jc->j_key, DB_DBT_USERMEM);
97 
98 	for (jc->j_curslist = curslist;
99 	    *jc->j_curslist != NULL; jc->j_curslist++)
100 		;
101 	if ((ret = __os_calloc((jc->j_curslist - curslist + 1),
102 	    sizeof(DBC *), &jc->j_curslist)) != 0)
103 		goto err;
104 	for (i = 0; curslist[i] != NULL; i++) {
105 		if (i != 0)
106 			F_SET(curslist[i], DBC_KEYSET);
107 		jc->j_curslist[i] = curslist[i];
108 	}
109 
110 	dbc->c_close = __db_join_close;
111 	dbc->c_del = __db_join_del;
112 	dbc->c_get = __db_join_get;
113 	dbc->c_put = __db_join_put;
114 	dbc->internal = jc;
115 	dbc->dbp = primary;
116 	jc->j_init = 1;
117 	jc->j_primary = primary;
118 
119 	*dbcp = dbc;
120 
121 	return (0);
122 
123 err:	if (jc != NULL) {
124 		if (jc->j_curslist != NULL)
125 			__os_free(jc->j_curslist,
126 			    (jc->j_curslist - curslist + 1) * sizeof(DBC *));
127 		__os_free(jc, sizeof(JOIN_CURSOR));
128 	}
129 	if (dbc != NULL)
130 		__os_free(dbc, sizeof(DBC));
131 	return (ret);
132 }
133 
134 static int
__db_join_put(dbc,key,data,flags)135 __db_join_put(dbc, key, data, flags)
136 	DBC *dbc;
137 	DBT *key;
138 	DBT *data;
139 	u_int32_t flags;
140 {
141 	DB_PANIC_CHECK(dbc->dbp);
142 
143 	COMPQUIET(key, NULL);
144 	COMPQUIET(data, NULL);
145 	COMPQUIET(flags, 0);
146 	return (EINVAL);
147 }
148 
149 static int
__db_join_del(dbc,flags)150 __db_join_del(dbc, flags)
151 	DBC *dbc;
152 	u_int32_t flags;
153 {
154 	DB_PANIC_CHECK(dbc->dbp);
155 
156 	COMPQUIET(flags, 0);
157 	return (EINVAL);
158 }
159 
160 static int
__db_join_get(dbc,key,data,flags)161 __db_join_get(dbc, key, data, flags)
162 	DBC *dbc;
163 	DBT *key, *data;
164 	u_int32_t flags;
165 {
166 	DB *dbp;
167 	DBC **cpp;
168 	JOIN_CURSOR *jc;
169 	int ret;
170 	u_int32_t operation;
171 
172 	dbp = dbc->dbp;
173 
174 	DB_PANIC_CHECK(dbp);
175 
176 	operation = LF_ISSET(DB_OPFLAGS_MASK);
177 	if (operation != 0 && operation != DB_JOIN_ITEM)
178 		return (__db_ferr(dbp->dbenv, "DBcursor->c_get", 0));
179 
180 	LF_CLR(DB_OPFLAGS_MASK);
181 	if ((ret =
182 	    __db_fchk(dbp->dbenv, "DBcursor->c_get", flags, DB_RMW)) != 0)
183 		return (ret);
184 
185 	jc = (JOIN_CURSOR *)dbc->internal;
186 retry:
187 	ret = jc->j_curslist[0]->c_get(jc->j_curslist[0],
188 	    &jc->j_key, key, jc->j_init ? DB_CURRENT : DB_NEXT_DUP);
189 
190 	if (ret == ENOMEM) {
191 		jc->j_key.ulen <<= 1;
192 		if ((ret = __os_realloc(&jc->j_key.data, jc->j_key.ulen)) != 0)
193 			return (ret);
194 		goto retry;
195 	}
196 	if (ret != 0)
197 		return (ret);
198 
199 	jc->j_init = 0;
200 	do {
201 		/*
202 		 * We have the first element; now look for it in the
203 		 * other cursors.
204 		 */
205 		for (cpp = jc->j_curslist + 1; *cpp != NULL; cpp++) {
206 retry2:			if ((ret = ((*cpp)->c_get)(*cpp,
207 			    &jc->j_key, key, DB_GET_BOTH)) == DB_NOTFOUND)
208 				break;
209 			if (ret == ENOMEM) {
210 				jc->j_key.ulen <<= 1;
211 				if ((ret = __os_realloc(&jc->j_key.data,
212 				    jc->j_key.ulen)) != 0)
213 					return (ret);
214 				goto retry2;
215 			}
216 			if (F_ISSET(*cpp, DBC_KEYSET)) {
217 				F_CLR(*cpp, DBC_KEYSET);
218 				F_SET(*cpp, DBC_CONTINUE);
219 			}
220 		}
221 
222 		/*
223 		 * If we got out of here with ret != 0, then we failed to
224 		 * find the duplicate in one of the files, so we go on to
225 		 * the next item in the outermost relation. If ret was
226 		 * equal to 0, then we've got something to return.
227 		 */
228 		if (ret == 0)
229 			break;
230 	} while ((ret = jc->j_curslist[0]->c_get(jc->j_curslist[0],
231 	    &jc->j_key, key,  DB_NEXT_DUP)) == 0);
232 
233 	/*
234 	 * If ret != 0 here, we've exhausted the first file.  Otherwise,
235 	 * key and data are set and we need to do the lookup on the
236 	 * primary.
237 	 */
238 	if (ret != 0)
239 		return (ret);
240 
241 	if (operation == DB_JOIN_ITEM)
242 		return (0);
243 	else
244 		return ((jc->j_primary->get)(jc->j_primary,
245 		    jc->j_curslist[0]->txn, key, data, 0));
246 }
247 
248 static int
__db_join_close(dbc)249 __db_join_close(dbc)
250 	DBC *dbc;
251 {
252 	JOIN_CURSOR *jc;
253 	int i;
254 
255 	DB_PANIC_CHECK(dbc->dbp);
256 
257 	jc = (JOIN_CURSOR *)dbc->internal;
258 
259 	/*
260 	 * Clear the optimization flag in the cursors.
261 	 */
262 	for (i = 0; jc->j_curslist[i] != NULL; i++)
263 		F_CLR(jc->j_curslist[i], DBC_CONTINUE | DBC_KEYSET);
264 
265 	__os_free(jc->j_curslist, 0);
266 	__os_free(jc->j_key.data, jc->j_key.ulen);
267 	__os_free(jc, sizeof(JOIN_CURSOR));
268 	__os_free(dbc, sizeof(DBC));
269 
270 	return (0);
271 }
272