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Diffstat (limited to 'db2/common/db_apprec.c')
-rw-r--r--db2/common/db_apprec.c129
1 files changed, 83 insertions, 46 deletions
diff --git a/db2/common/db_apprec.c b/db2/common/db_apprec.c
index 188c6b9f95..7a42e13317 100644
--- a/db2/common/db_apprec.c
+++ b/db2/common/db_apprec.c
@@ -11,12 +11,13 @@
static const char copyright[] =
"@(#) Copyright (c) 1997\n\
Sleepycat Software Inc. All rights reserved.\n";
-static const char sccsid[] = "@(#)db_apprec.c 10.19 (Sleepycat) 11/23/97";
+static const char sccsid[] = "@(#)db_apprec.c 10.23 (Sleepycat) 1/17/98";
#endif
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
+#include <errno.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
@@ -44,9 +45,9 @@ __db_apprec(dbenv, flags)
{
DBT data;
DB_LOG *lp;
- DB_LSN ckp_lsn, first_lsn, lsn, tmp_lsn;
+ DB_LSN ckp_lsn, first_lsn, lsn;
time_t now;
- int first_flag, is_thread, ret;
+ int is_thread, ret;
void *txninfo;
lp = dbenv->lg_info;
@@ -63,73 +64,109 @@ __db_apprec(dbenv, flags)
F_CLR(lp, DB_AM_THREAD);
/*
- * Read forward through the log, opening the appropriate files so that
- * we can call recovery routines. In general, we start at the last
- * checkpoint prior to the last checkpointed LSN. For catastrophic
- * recovery, we begin at the first LSN that appears in any log file
- * (log_get figures this out for us when we pass it the DB_FIRST flag).
+ * Recovery is done in three passes:
+ * Pass #1:
+ * Read forward through the log from the last checkpoint to the
+ * end of the log, opening and closing files so that at the end
+ * of the log we have the "current" set of files open.
+ * Pass #2:
+ * Read backward through the log undoing any uncompleted TXNs.
+ * If doing catastrophic recovery, we read to the beginning of
+ * the log, otherwise, to the most recent checkpoint that occurs
+ * before the most recent checkpoint LSN, which is returned by
+ * __log_findckp(). During this pass, checkpoint file information
+ * is ignored, and file openings and closings are undone.
+ * Pass #3:
+ * Read forward through the log from the LSN found in pass #2,
+ * redoing any committed TXNs. During this pass, checkpoint
+ * file information is ignored, and file openings and closings
+ * are redone.
*/
- if (LF_ISSET(DB_RECOVER_FATAL))
- first_flag = DB_FIRST;
- else {
- if ((ret = __log_findckp(lp, &lsn)) == DB_NOTFOUND)
- goto out;
- first_flag = DB_SET;
- }
- /* If we're a threaded application, we have to allocate space. */
+ /*
+ * Find the last checkpoint in the log. This is the point from which
+ * we want to begin pass #1 (the TXN_OPENFILES pass).
+ */
memset(&data, 0, sizeof(data));
- if ((ret = log_get(lp, &lsn, &data, first_flag)) != 0) {
- __db_err(dbenv, "Failure: unable to get log record");
- if (first_flag == DB_SET)
- __db_err(dbenv, "Retrieving LSN %lu %lu",
- (u_long)lsn.file, (u_long)lsn.offset);
- else
- __db_err(dbenv, "Retrieving first LSN");
- goto out;
+ if ((ret = log_get(lp, &ckp_lsn, &data, DB_CHECKPOINT)) != 0) {
+ /*
+ * If we don't find a checkpoint, start from the beginning.
+ * If that fails, we're done. Note, we require that there
+ * be log records if we're performing recovery, and fail if
+ * there aren't.
+ */
+ if ((ret = log_get(lp, &ckp_lsn, &data, DB_FIRST)) != 0) {
+ __db_err(dbenv, "First log record not found");
+ if (ret == DB_NOTFOUND)
+ ret = EINVAL;
+ goto out;
+ }
}
- first_lsn = lsn;
+ /*
+ * Now, ckp_lsn is either the lsn of the last checkpoint or the lsn
+ * of the first record in the log. Begin the TXN_OPENFILES pass from
+ * that lsn, and proceed to the end of the log.
+ */
+ lsn = ckp_lsn;
for (;;) {
ret = __db_dispatch(lp, &data, &lsn, TXN_OPENFILES, txninfo);
if (ret != 0 && ret != DB_TXN_CKP)
goto msgerr;
- if ((ret =
- log_get(dbenv->lg_info, &lsn, &data, DB_NEXT)) != 0) {
- if (ret != DB_NOTFOUND)
- goto out;
- break;
+ if ((ret = log_get(lp, &lsn, &data, DB_NEXT)) != 0) {
+ if (ret == DB_NOTFOUND)
+ break;
+ goto out;
}
}
/*
- * Initialize the ckp_lsn to 0,0. If we never find a valid
- * checkpoint in the log, then leaving ckp_lsn at 0,0 is correct.
+ * Pass #2.
+ *
+ * Before we can begin pass #2, backward roll phase, we determine how
+ * far back in the log to recover. If we are doing catastrophic
+ * recovery, then we go as far back as we have files. If we are
+ * doing normal recovery, we go as back to the most recent checkpoint
+ * that occurs before the most recent checkpoint LSN.
*/
- ZERO_LSN(ckp_lsn);
+ if (LF_ISSET(DB_RECOVER_FATAL)) {
+ ZERO_LSN(first_lsn);
+ } else
+ if ((ret = __log_findckp(lp, &first_lsn)) == DB_NOTFOUND) {
+ /*
+ * If recovery was specified, there must be log files.
+ * If we don't find one, it's an error. (This should
+ * have been caught above, when a log_get() of DB_FIRST
+ * or DB_CHECKPOINT succeeded, but paranoia is good.)
+ */
+ ret = EINVAL;
+ goto out;
+ }
for (ret = log_get(lp, &lsn, &data, DB_LAST);
ret == 0 && log_compare(&lsn, &first_lsn) > 0;
- ret = log_get(lp,&lsn, &data, DB_PREV)) {
- tmp_lsn = lsn;
+ ret = log_get(lp, &lsn, &data, DB_PREV)) {
ret = __db_dispatch(lp,
&data, &lsn, TXN_BACKWARD_ROLL, txninfo);
- if (ret == DB_TXN_CKP) {
- if (IS_ZERO_LSN(ckp_lsn))
- ckp_lsn = tmp_lsn;
- ret = 0;
- } else if (ret != 0)
- goto msgerr;
+ 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(lp, &lsn, &data, DB_NEXT);
ret == 0; ret = log_get(lp, &lsn, &data, DB_NEXT)) {
ret = __db_dispatch(lp, &data, &lsn, TXN_FORWARD_ROLL, txninfo);
- if (ret == DB_TXN_CKP)
- ret = 0;
- else if (ret != 0)
- goto msgerr;
+ if (ret != 0)
+ if (ret != DB_TXN_CKP)
+ goto msgerr;
+ else
+ ret = 0;
}
if (ret != DB_NOTFOUND)
goto out;
@@ -149,7 +186,7 @@ __db_apprec(dbenv, flags)
goto out;
if (dbenv->db_verbose) {
- __db_err(lp->dbenv, "Recovery complete at %s", ctime(&now));
+ __db_err(lp->dbenv, "Recovery complete at %.24s", ctime(&now));
__db_err(lp->dbenv, "%s %lu %s [%lu][%lu]",
"Maximum transaction id",
(u_long)dbenv->tx_info->region->last_txnid,