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authorUlrich Drepper <drepper@redhat.com>1999-06-13 13:36:34 +0000
committerUlrich Drepper <drepper@redhat.com>1999-06-13 13:36:34 +0000
commitec239360d13518a13f572b635d036c7d10028010 (patch)
treebdb5111363f45d2107849c2456b575d72779174c /db2/log/log_findckp.c
parentfc3703521650a9b6db910a50c4fc0f410496e134 (diff)
Update.
* db2/Makefile (distribute): Remove files which do not exist anymore.
Diffstat (limited to 'db2/log/log_findckp.c')
-rw-r--r--db2/log/log_findckp.c32
1 files changed, 22 insertions, 10 deletions
diff --git a/db2/log/log_findckp.c b/db2/log/log_findckp.c
index 1f717b49e7..ab13c8380e 100644
--- a/db2/log/log_findckp.c
+++ b/db2/log/log_findckp.c
@@ -8,7 +8,7 @@
#include "config.h"
#ifndef lint
-static const char sccsid[] = "@(#)log_findckp.c 10.15 (Sleepycat) 4/26/98";
+static const char sccsid[] = "@(#)log_findckp.c 10.17 (Sleepycat) 9/17/98";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
@@ -28,7 +28,10 @@ static const char sccsid[] = "@(#)log_findckp.c 10.15 (Sleepycat) 4/26/98";
* __log_findckp --
*
* Looks for the most recent checkpoint that occurs before the most recent
- * checkpoint LSN. This is the point from which recovery can start and the
+ * checkpoint LSN, subject to the constraint that there must be at least two
+ * checkpoints. The reason you need two checkpoints is that you might have
+ * crashed during the most recent one and may not have a copy of all the
+ * open files. This is the point from which recovery can start and the
* point up to which archival/truncation can take place. Checkpoints in
* the log look like:
*
@@ -56,7 +59,7 @@ __log_findckp(lp, lsnp)
DB_LSN *lsnp;
{
DBT data;
- DB_LSN ckp_lsn, last_ckp, next_lsn;
+ DB_LSN ckp_lsn, final_ckp, last_ckp, next_lsn;
__txn_ckp_args *ckp_args;
int ret, verbose;
@@ -77,16 +80,17 @@ __log_findckp(lp, lsnp)
return (ret);
}
+ final_ckp = last_ckp;
next_lsn = last_ckp;
do {
if (F_ISSET(lp, DB_AM_THREAD))
- __db_free(data.data);
+ __os_free(data.data, data.size);
if ((ret = log_get(lp, &next_lsn, &data, DB_SET)) != 0)
return (ret);
if ((ret = __txn_ckp_read(data.data, &ckp_args)) != 0) {
if (F_ISSET(lp, DB_AM_THREAD))
- __db_free(data.data);
+ __os_free(data.data, data.size);
return (ret);
}
if (IS_ZERO_LSN(ckp_lsn))
@@ -103,12 +107,19 @@ __log_findckp(lp, lsnp)
}
last_ckp = next_lsn;
next_lsn = ckp_args->last_ckp;
- __db_free(ckp_args);
+ __os_free(ckp_args, sizeof(*ckp_args));
+
+ /*
+ * Keep looping until either you 1) run out of checkpoints,
+ * 2) you've found a checkpoint before the most recent
+ * checkpoint's LSN and you have at least 2 checkpoints.
+ */
} while (!IS_ZERO_LSN(next_lsn) &&
- log_compare(&last_ckp, &ckp_lsn) > 0);
+ (log_compare(&last_ckp, &ckp_lsn) > 0 ||
+ log_compare(&final_ckp, &last_ckp) == 0));
if (F_ISSET(lp, DB_AM_THREAD))
- __db_free(data.data);
+ __os_free(data.data, data.size);
/*
* At this point, either, next_lsn is ZERO or ckp_lsn is the
@@ -117,11 +128,12 @@ __log_findckp(lp, lsnp)
* next_lsn must be 0 and we need to roll forward from the
* beginning of the log.
*/
- if (log_compare(&last_ckp, &ckp_lsn) > 0) {
+ if (log_compare(&last_ckp, &ckp_lsn) > 0 ||
+ log_compare(&final_ckp, &last_ckp) == 0) {
get_first: if ((ret = log_get(lp, &last_ckp, &data, DB_FIRST)) != 0)
return (ret);
if (F_ISSET(lp, DB_AM_THREAD))
- __db_free(data.data);
+ __os_free(data.data, data.size);
}
*lsnp = last_ckp;