1 /*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 1996, 1997, 1998
5 * Sleepycat Software. All rights reserved.
6 */
7
8 #include "config.h"
9
10 #ifndef lint
11 static const char copyright[] =
12 "@(#) Copyright (c) 1996, 1997, 1998\n\
13 Sleepycat Software Inc. All rights reserved.\n";
14 static const char sccsid[] = "@(#)db_apprec.c 10.33 (Sleepycat) 10/5/98";
15 #endif
16
17 #ifndef NO_SYSTEM_INCLUDES
18 #include <sys/types.h>
19
20 #include <errno.h>
21 #include <string.h>
22 #include <time.h>
23 #endif
24
25 #include "db_int.h"
26 #include "shqueue.h"
27 #include "db_page.h"
28 #include "db_dispatch.h"
29 #include "db_am.h"
30 #include "log.h"
31 #include "txn.h"
32 #include "common_ext.h"
33
34 /*
35 * __db_apprec --
36 * Perform recovery.
37 *
38 * PUBLIC: int __db_apprec __P((DB_ENV *, u_int32_t));
39 */
40 int
__db_apprec(dbenv,flags)41 __db_apprec(dbenv, flags)
42 DB_ENV *dbenv;
43 u_int32_t flags;
44 {
45 DBT data;
46 DB_LOG *lp;
47 DB_LSN ckp_lsn, first_lsn, lsn, open_lsn;
48 __txn_ckp_args *ckp_args;
49 time_t now;
50 u_int32_t is_thread;
51 int ret;
52 void *txninfo;
53
54 lp = dbenv->lg_info;
55
56 /* Initialize the transaction list. */
57 if ((ret = __db_txnlist_init(&txninfo)) != 0)
58 return (ret);
59
60 /*
61 * Save the state of the thread flag -- we don't need it on at the
62 * moment because we're single-threaded until recovery is complete.
63 */
64 is_thread = F_ISSET(lp, DB_AM_THREAD);
65 F_CLR(lp, DB_AM_THREAD);
66
67 /*
68 * Recovery is done in three passes:
69 * Pass #0:
70 * We need to find the position from which we will open files
71 * We need to open files beginning with the last to next
72 * checkpoint because we might have crashed after writing the
73 * last checkpoint record, but before having written out all
74 * the open file information.
75 * Pass #1:
76 * Read forward through the log from the second to last checkpoint
77 * opening and closing files so that at the end of the log we have
78 * the "current" set of files open.
79 * Pass #2:
80 * Read backward through the log undoing any uncompleted TXNs.
81 * If doing catastrophic recovery, we read to the beginning of
82 * the log, otherwise, to the most recent checkpoint that occurs
83 * before the most recent checkpoint LSN, which is returned by
84 * __log_findckp(). During this pass, checkpoint file information
85 * is ignored, and file openings and closings are undone.
86 * Pass #3:
87 * Read forward through the log from the LSN found in pass #2,
88 * redoing any committed TXNs. During this pass, checkpoint
89 * file information is ignored, and file openings and closings
90 * are redone.
91 */
92
93 /*
94 * Find the second to last checkpoint in the log. This is the point
95 * from which we want to begin pass #1 (the TXN_OPENFILES pass).
96 */
97 memset(&data, 0, sizeof(data));
98 ckp_args = NULL;
99
100 if ((ret = log_get(lp, &ckp_lsn, &data, DB_CHECKPOINT)) != 0) {
101 /*
102 * If we don't find a checkpoint, start from the beginning.
103 * If that fails, we're done. Note, we do not require that
104 * there be log records if we're performing recovery.
105 */
106 first: if ((ret = log_get(lp, &ckp_lsn, &data, DB_FIRST)) != 0) {
107 if (ret == DB_NOTFOUND)
108 ret = 0;
109 else
110 __db_err(dbenv, "First log record not found");
111 goto out;
112 }
113 open_lsn = ckp_lsn;
114 } else if ((ret = __txn_ckp_read(data.data, &ckp_args)) != 0) {
115 __db_err(dbenv, "Invalid checkpoint record at [%ld][%ld]\n",
116 (u_long)ckp_lsn.file, (u_long)ckp_lsn.offset);
117 goto out;
118 } else if (IS_ZERO_LSN(ckp_args->last_ckp) ||
119 (ret = log_get(lp, &ckp_args->last_ckp, &data, DB_SET)) != 0)
120 goto first;
121 else
122 open_lsn = ckp_args->last_ckp;
123
124 /*
125 * Now, ckp_lsn is either the lsn of the last checkpoint or the lsn
126 * of the first record in the log. Open_lsn is the second to last
127 * checkpoint or the beinning of the log; begin the TXN_OPENFILES
128 * pass from that lsn, and proceed to the end of the log.
129 */
130 lsn = open_lsn;
131 for (;;) {
132 if (dbenv->tx_recover != NULL)
133 ret = dbenv->tx_recover(lp,
134 &data, &lsn, TXN_OPENFILES, txninfo);
135 else
136 ret = __db_dispatch(lp,
137 &data, &lsn, TXN_OPENFILES, txninfo);
138 if (ret != 0 && ret != DB_TXN_CKP)
139 goto msgerr;
140 if ((ret = log_get(lp, &lsn, &data, DB_NEXT)) != 0) {
141 if (ret == DB_NOTFOUND)
142 break;
143 goto out;
144 }
145 }
146
147 /*
148 * Pass #2.
149 *
150 * Before we can begin pass #2, backward roll phase, we determine how
151 * far back in the log to recover. If we are doing catastrophic
152 * recovery, then we go as far back as we have files. If we are
153 * doing normal recovery, we go as back to the most recent checkpoint
154 * that occurs before the most recent checkpoint LSN.
155 */
156 if (LF_ISSET(DB_RECOVER_FATAL)) {
157 ZERO_LSN(first_lsn);
158 } else
159 if ((ret = __log_findckp(lp, &first_lsn)) == DB_NOTFOUND) {
160 /*
161 * We don't require that log files exist if recovery
162 * was specified.
163 */
164 ret = 0;
165 goto out;
166 }
167
168 if (dbenv->db_verbose)
169 __db_err(lp->dbenv, "Recovery starting from [%lu][%lu]",
170 (u_long)first_lsn.file, (u_long)first_lsn.offset);
171
172 for (ret = log_get(lp, &lsn, &data, DB_LAST);
173 ret == 0 && log_compare(&lsn, &first_lsn) > 0;
174 ret = log_get(lp, &lsn, &data, DB_PREV)) {
175 if (dbenv->tx_recover != NULL)
176 ret = dbenv->tx_recover(lp,
177 &data, &lsn, TXN_BACKWARD_ROLL, txninfo);
178 else
179 ret = __db_dispatch(lp,
180 &data, &lsn, TXN_BACKWARD_ROLL, txninfo);
181 if (ret != 0)
182 if (ret != DB_TXN_CKP)
183 goto msgerr;
184 else
185 ret = 0;
186 }
187 if (ret != 0 && ret != DB_NOTFOUND)
188 goto out;
189
190 /*
191 * Pass #3.
192 */
193 for (ret = log_get(lp, &lsn, &data, DB_NEXT);
194 ret == 0; ret = log_get(lp, &lsn, &data, DB_NEXT)) {
195 if (dbenv->tx_recover != NULL)
196 ret = dbenv->tx_recover(lp,
197 &data, &lsn, TXN_FORWARD_ROLL, txninfo);
198 else
199 ret = __db_dispatch(lp,
200 &data, &lsn, TXN_FORWARD_ROLL, txninfo);
201 if (ret != 0)
202 if (ret != DB_TXN_CKP)
203 goto msgerr;
204 else
205 ret = 0;
206 }
207 if (ret != DB_NOTFOUND)
208 goto out;
209
210 /* Now close all the db files that are open. */
211 __log_close_files(lp);
212
213 /*
214 * Now set the last checkpoint lsn and the current time,
215 * take a checkpoint, and reset the txnid.
216 */
217 (void)time(&now);
218 dbenv->tx_info->region->last_ckp = ckp_lsn;
219 dbenv->tx_info->region->time_ckp = (u_int32_t)now;
220 if ((ret = txn_checkpoint(dbenv->tx_info, 0, 0)) != 0)
221 goto out;
222 dbenv->tx_info->region->last_txnid = TXN_MINIMUM;
223
224 if (dbenv->db_verbose) {
225 __db_err(lp->dbenv, "Recovery complete at %.24s", ctime(&now));
226 __db_err(lp->dbenv, "%s %lx %s [%lu][%lu]",
227 "Maximum transaction id",
228 ((DB_TXNHEAD *)txninfo)->maxid,
229 "Recovery checkpoint",
230 (u_long)dbenv->tx_info->region->last_ckp.file,
231 (u_long)dbenv->tx_info->region->last_ckp.offset);
232 }
233
234 if (0) {
235 msgerr: __db_err(dbenv, "Recovery function for LSN %lu %lu failed",
236 (u_long)lsn.file, (u_long)lsn.offset);
237 }
238
239 out: F_SET(lp, is_thread);
240 __db_txnlist_end(txninfo);
241 if (ckp_args != NULL)
242 __os_free(ckp_args, sizeof(*ckp_args));
243
244 return (ret);
245 }
246