/*- * See the file LICENSE for redistribution information. * * Copyright (c) 1996-2001 * Sleepycat Software. All rights reserved. */ #include "db_config.h" #ifndef lint static const char copyright[] = "Copyright (c) 1996-2001\nSleepycat Software Inc. All rights reserved.\n"; static const char revid[] = "$Id: env_recover.c,v 11.49 2001/07/11 21:04:52 margo Exp $"; #endif #ifndef NO_SYSTEM_INCLUDES #include #if TIME_WITH_SYS_TIME #include #include #else #if HAVE_SYS_TIME_H #include #else #include #endif #endif #include #endif #include "db_int.h" #include "db_page.h" #include "db_dispatch.h" #include "db_am.h" #include "log.h" #include "txn.h" static int __log_earliest __P((DB_ENV *, int32_t *, DB_LSN *)); static double __lsn_diff __P((DB_LSN *, DB_LSN *, DB_LSN *, u_int32_t, int)); /* * __db_apprec -- * Perform recovery. * * PUBLIC: int __db_apprec __P((DB_ENV *, u_int32_t)); */ int __db_apprec(dbenv, flags) DB_ENV *dbenv; u_int32_t flags; { DBT data; DB_LSN ckp_lsn, first_lsn, last_lsn, lowlsn, lsn, open_lsn; DB_TXNREGION *region; __txn_ckp_args *ckp_args; time_t now, tlow; double nfiles; int32_t low; int is_thread, progress, ret; void *txninfo; COMPQUIET(nfiles, (double)0); ckp_args = NULL; /* * Save the state of the thread flag -- we don't need it on at the * moment because we're single-threaded until recovery is complete. */ is_thread = F_ISSET(dbenv, DB_ENV_THREAD) ? 1 : 0; F_CLR(dbenv, DB_ENV_THREAD); /* Set in-recovery flags. */ F_SET((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER); region = ((DB_TXNMGR *)dbenv->tx_handle)->reginfo.primary; F_SET(region, TXN_IN_RECOVERY); /* * If the user is specifying recovery to a particular point in time, * verify that the logs present are sufficient to do this. */ ZERO_LSN(lowlsn); if (dbenv->tx_timestamp != 0) { if ((ret = __log_earliest(dbenv, &low, &lowlsn)) != 0) return (ret); if ((int32_t)dbenv->tx_timestamp < low) { char t1[30], t2[30]; strcpy(t1, ctime(&dbenv->tx_timestamp)); tlow = (time_t)low; strcpy(t2, ctime(&tlow)); __db_err(dbenv, "Invalid recovery timestamp %.*s; earliest time is %.*s", 24, t1, 24, t2); return (EINVAL); } } /* Initialize the transaction list. */ if ((ret = __db_txnlist_init(dbenv, &txninfo)) != 0) return (ret); /* * Recovery is done in three passes: * Pass #0: * We need to find the position from which we will open files. * We need to open files beginning with the earliest of the next * to last checkpoint, the most recent checkpoint LSN, and a * checkpoint LSN before the recovery timestamp, if specified. We * need two checkpoints, because we might have crashed after * writing the last checkpoint record, but before having written * out all the open file information. We need to be before the * most recent checkpoint LSN because we are also going to collect * information about which transactions were begun before we * start rolling forward. Those that were should never be undone * because queue cannot use LSNs to determine what operations can * safely be aborted and it cannot rollback operations in * transactions for which there may be records not processed * during recovery. We need to consider earlier points in time * in case we are recovering to a particular timestamp. * * Pass #1: * Read forward through the log from the position found in pass 0 * opening and closing files, and recording transactions for which * we've seen their first record (the transaction's prev_lsn is * 0,0). At the end of this pass, we know all transactions for * which we've seen begins and we have the "current" set of files * open. * * Pass #2: * Read backward through the log undoing any uncompleted TXNs. * There are three cases: * 1. If doing catastrophic recovery, we read to the * beginning of the log * 2. If we are doing normal reovery, then we have to roll * back to the most recent checkpoint that occurs * before the most recent checkpoint LSN, which is * returned by __log_findckp(). * 3. If we are recovering to a point in time, then we have * to roll back to the checkpoint whose ckp_lsn is earlier * than the specified time. __log_earliest will figure * this out for us. * In case 2, "uncompleted TXNs" include all those who commited * after the user's specified timestamp. * * Pass #3: * Read forward through the log from the LSN found in pass #2, * redoing any committed TXNs (which commited after any user- * specified rollback point). During this pass, checkpoint * file information is ignored, and file openings and closings * are redone. */ /* * Find out the last lsn, so that we can estimate how far along we * are in recovery. This will help us determine how much log there * is between the first LSN that we're going to be working with and * the last one. We assume that each of the three phases takes the * same amount of time (a false assumption) and then use the %-age * of the amount of log traversed to figure out how much of the * pass we've accomplished. * * If we can't find any log records, we're kind of done. */ memset(&data, 0, sizeof(data)); if (dbenv->db_feedback != NULL && (ret = log_get(dbenv, &last_lsn, &data, DB_LAST)) != 0) { if (ret == DB_NOTFOUND) ret = 0; else __db_err(dbenv, "Last log record not found"); goto out; } /* * Pass #0 * Find the LSN from which we begin OPENFILES. It is the minimum of * 1) the second to last checkpoint in the log 2) the LSN of the * ckp_lsn in the last checkpoint, and 3) the checkpoint before the * ckp_lsn before the recovery timestamp. */ if (LF_ISSET(DB_RECOVER_FATAL)) { if ((ret = log_get(dbenv, &ckp_lsn, &data, DB_FIRST)) != 0) { if (ret == DB_NOTFOUND) ret = 0; else __db_err(dbenv, "First log record not found"); goto out; } open_lsn = ckp_lsn; } else { /* * Find the first LSN that we need to consider. This * is either the one in the last checkpoint, the first, * LSN in the log, or the one selected to make timestamp- * based recovery work. */ if ((ret = __log_findckp(dbenv, &first_lsn)) == DB_NOTFOUND) { /* * We don't require that log files exist if recovery * was specified. */ ret = 0; goto out; } if (ret != 0) goto out; /* * XXX We just read the last checkpoint in log_findckp; it * would be nice if we didn't have to do it again. */ if ((ret = log_get(dbenv, &ckp_lsn, &data, DB_CHECKPOINT)) != 0) { /* * If we don't find a checkpoint, start from the * beginning. */ open_lsn = ckp_lsn = first_lsn; goto get_it; } else if ((ret = __txn_ckp_read(dbenv, data.data, &ckp_args)) != 0) { __db_err(dbenv, "Invalid checkpoint record at [%ld][%ld]", (u_long)ckp_lsn.file, (u_long)ckp_lsn.offset); goto out; } else if (IS_ZERO_LSN(ckp_args->last_ckp) || (ret = log_get(dbenv, &ckp_args->last_ckp, &data, DB_SET)) != 0) { open_lsn = ckp_lsn = first_lsn; goto get_it; } else { /* * Because queue uses record locking we need back up * till we know all previous transactions are on disk. * This info is contained in the last checkpoint. */ if (log_compare(&ckp_args->last_ckp, &first_lsn) < 0) open_lsn = ckp_args->last_ckp; else open_lsn = first_lsn; if (dbenv->tx_timestamp != 0 && log_compare(&lowlsn, &open_lsn) < 0) open_lsn = lowlsn; if (log_compare(&open_lsn, &ckp_args->last_ckp) !=0) { get_it: if ((ret = log_get(dbenv, &open_lsn, &data, DB_SET)) != 0) goto out; } } } if (dbenv->db_feedback != NULL) { if (last_lsn.file == open_lsn.file) nfiles = (double)(last_lsn.offset - open_lsn.offset) / dbenv->lg_max; else nfiles = (double)(last_lsn.file - open_lsn.file) + (double)(dbenv->lg_max - open_lsn.offset + last_lsn.offset) / dbenv->lg_max; /* We are going to divide by nfiles; make sure it isn't 0. */ if (nfiles == 0) nfiles = (double)0.001; } /* * Pass #1 * Now, ckp_lsn is either the lsn of the last checkpoint * or the lsn of the first record in the log. Open_lsn is * either the second to last checkpoint, the beinning of the log, * or the point to which we'll recover. That is the point from * which we being OPENFILES. */ if ((ret = __env_openfiles(dbenv, txninfo, &data, &open_lsn, &last_lsn, nfiles, 1)) != 0) goto out; /* * Pass #2. * * We used open_lsn to tell us how far back we need to recover, * use it here. */ first_lsn = open_lsn; if (FLD_ISSET(dbenv->verbose, DB_VERB_RECOVERY)) __db_err(dbenv, "Recovery starting from [%lu][%lu]", (u_long)first_lsn.file, (u_long)first_lsn.offset); for (ret = log_get(dbenv, &lsn, &data, DB_LAST); ret == 0 && log_compare(&lsn, &first_lsn) >= 0; ret = log_get(dbenv, &lsn, &data, DB_PREV)) { if (dbenv->db_feedback != NULL) { progress = 34 + (int)(33 * (__lsn_diff(&open_lsn, &last_lsn, &lsn, dbenv->lg_max, 0) / nfiles)); dbenv->db_feedback(dbenv, DB_RECOVER, progress); } ret = __db_dispatch(dbenv, &data, &lsn, DB_TXN_BACKWARD_ROLL, txninfo); if (ret != 0) { if (ret != DB_TXN_CKP) goto msgerr; else ret = 0; } } if (ret != 0 && ret != DB_NOTFOUND) goto out; /* * Pass #3. */ for (ret = log_get(dbenv, &lsn, &data, DB_NEXT); ret == 0; ret = log_get(dbenv, &lsn, &data, DB_NEXT)) { if (dbenv->db_feedback != NULL) { progress = 67 + (int)(33 * (__lsn_diff(&open_lsn, &last_lsn, &lsn, dbenv->lg_max, 1) / nfiles)); dbenv->db_feedback(dbenv, DB_RECOVER, progress); } ret = __db_dispatch(dbenv, &data, &lsn, DB_TXN_FORWARD_ROLL, txninfo); if (ret != 0) { if (ret != DB_TXN_CKP) goto msgerr; else ret = 0; } } if (ret != DB_NOTFOUND) goto out; /* * Process any pages that were on the limbo list * and move them to the free list. Do this * before checkpointing the database. */ if ((ret = __db_do_the_limbo(dbenv, txninfo)) != 0) goto out; /* * Now set the last checkpoint lsn and the current time, * take a checkpoint, and reset the txnid. */ (void)time(&now); region->last_txnid = ((DB_TXNHEAD *)txninfo)->maxid; region->last_ckp = ckp_lsn; region->time_ckp = (u_int32_t)now; /* * Take two checkpoints so that we don't re-recover any of the * work we've already done. */ if ((ret = txn_checkpoint(dbenv, 0, 0, DB_FORCE)) != 0) goto out; /* Now close all the db files that are open. */ __log_close_files(dbenv); if ((ret = txn_checkpoint(dbenv, 0, 0, DB_FORCE)) != 0) goto out; if (region->nrestores == 0) region->last_txnid = TXN_MINIMUM; if (FLD_ISSET(dbenv->verbose, DB_VERB_RECOVERY)) { __db_err(dbenv, "Recovery complete at %.24s", ctime(&now)); __db_err(dbenv, "%s %lx %s [%lu][%lu]", "Maximum transaction ID", ((DB_TXNHEAD *)txninfo)->maxid, "Recovery checkpoint", (u_long)region->last_ckp.file, (u_long)region->last_ckp.offset); } if (0) { msgerr: __db_err(dbenv, "Recovery function for LSN %lu %lu failed", (u_long)lsn.file, (u_long)lsn.offset); } out: __db_txnlist_end(dbenv, txninfo); if (ckp_args != NULL) __os_free(dbenv, ckp_args, sizeof(*ckp_args)); dbenv->tx_timestamp = 0; /* Restore the state of the thread flag, clear in-recovery flags. */ if (is_thread) F_SET(dbenv, DB_ENV_THREAD); F_CLR((DB_LOG *)dbenv->lg_handle, DBLOG_RECOVER); F_CLR(region, TXN_IN_RECOVERY); return (ret); } /* * Figure out how many logfiles we have processed. If we are moving * forward (is_forward != 0), then we're computing current - low. If * we are moving backward, we are computing high - current. max is * the number of bytes per logfile. */ static double __lsn_diff(low, high, current, max, is_forward) DB_LSN *low, *high, *current; u_int32_t max; int is_forward; { double nf; /* * There are three cases in each direction. If you are in the * same file, then all you need worry about is the difference in * offsets. If you are in different files, then either your offsets * put you either more or less than the integral difference in the * number of files -- we need to handle both of these. */ if (is_forward) { if (current->file == low->file) nf = (double)(current->offset - low->offset) / max; else if (current->offset < low->offset) nf = (double)(current->file - low->file - 1) + (double)(max - low->offset + current->offset) / max; else nf = (double)(current->file - low->file) + (double)(current->offset - low->offset) / max; } else { if (current->file == high->file) nf = (double)(high->offset - current->offset) / max; else if (current->offset > high->offset) nf = (double)(high->file - current->file - 1) + (double) (max - current->offset + high->offset) / max; else nf = (double)(high->file - current->file) + (double)(high->offset - current->offset) / max; } return (nf); } /* * __log_earliest -- * * Return the earliest recovery point for the log files present. The * earliest recovery time is the time stamp of the first checkpoint record * whose checkpoint LSN is greater than the first LSN we process. */ static int __log_earliest(dbenv, lowtime, lowlsn) DB_ENV *dbenv; int32_t *lowtime; DB_LSN *lowlsn; { DB_LSN first_lsn, lsn; DBT data; __txn_ckp_args *ckpargs; u_int32_t rectype; int cmp, ret; memset(&data, 0, sizeof(data)); /* * Read forward through the log looking for the first checkpoint * record whose ckp_lsn is greater than first_lsn. */ for (ret = log_get(dbenv, &first_lsn, &data, DB_FIRST); ret == 0; ret = log_get(dbenv, &lsn, &data, DB_NEXT)) { if (ret != 0) break; memcpy(&rectype, data.data, sizeof(rectype)); if (rectype != DB_txn_ckp) continue; if ((ret = __txn_ckp_read(dbenv, data.data, &ckpargs)) == 0) { cmp = log_compare(&ckpargs->ckp_lsn, &first_lsn); *lowlsn = ckpargs->ckp_lsn; *lowtime = ckpargs->timestamp; __os_free(dbenv, ckpargs, 0); if (cmp >= 0) break; } } return (ret); } /* * __env_openfiles -- * Perform the pass of recovery that opens files. This is used * both during recover and before txn_recover, since we need files * open in order to abort prepared, but not yet committed transactions. * See the comments in db_apprec for a detailed description of the * various recovery passes. * * If we are not doing feedback processing (i.e., we are doing txn_recover * processing and in_recovery is zero), then last_lsn can be NULL. * * PUBLIC: int __env_openfiles __P((DB_ENV *, * PUBLIC: void *, DBT *, DB_LSN *, DB_LSN *, double, int)); */ int __env_openfiles(dbenv, txninfo, data, open_lsn, last_lsn, nfiles, in_recovery) DB_ENV *dbenv; void *txninfo; DBT *data; DB_LSN *open_lsn, *last_lsn; int in_recovery; double nfiles; { DB_LSN lsn; int progress, ret; lsn = *open_lsn; for (;;) { if (in_recovery && dbenv->db_feedback != NULL) { DB_ASSERT(last_lsn != NULL); progress = (int)(33 * (__lsn_diff(open_lsn, last_lsn, &lsn, dbenv->lg_max, 1) / nfiles)); dbenv->db_feedback(dbenv, DB_RECOVER, progress); } ret = __db_dispatch(dbenv, data, &lsn, in_recovery ? DB_TXN_OPENFILES : DB_TXN_POPENFILES, txninfo); if (ret != 0 && ret != DB_TXN_CKP) { __db_err(dbenv, "Recovery function for LSN %lu %lu failed", (u_long)lsn.file, (u_long)lsn.offset); break; } if ((ret = log_get(dbenv, &lsn, data, DB_NEXT)) != 0) { if (ret == DB_NOTFOUND) ret = 0; break; } } return (ret); }