diff options
Diffstat (limited to 'db2/log/log_findckp.c')
| -rw-r--r-- | db2/log/log_findckp.c | 32 |
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; |