diff options
Diffstat (limited to 'debian/htdig/htdig-3.2.0b6/db/log_findckp.c')
| -rw-r--r-- | debian/htdig/htdig-3.2.0b6/db/log_findckp.c | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/debian/htdig/htdig-3.2.0b6/db/log_findckp.c b/debian/htdig/htdig-3.2.0b6/db/log_findckp.c new file mode 100644 index 00000000..af2339b5 --- /dev/null +++ b/debian/htdig/htdig-3.2.0b6/db/log_findckp.c @@ -0,0 +1,136 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996, 1997, 1998, 1999 + * Sleepycat Software. All rights reserved. + */ + +#include "db_config.h" + +#ifndef lint +static const char sccsid[] = "@(#)log_findckp.c 11.1 (Sleepycat) 7/24/99"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <errno.h> +#include <string.h> +#endif + +#include "db_int.h" +#include "log.h" +#include "txn.h" + +/* + * CDB___log_findckp -- + * + * Looks for the most recent checkpoint that occurs before the most recent + * 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: + * + * ------------------------------------------------------------------- + * | ckp A, ckplsn 100 | .... record .... | ckp B, ckplsn 600 | ... + * ------------------------------------------------------------------- + * LSN 500 LSN 1000 + * + * If we read what log returns from using the DB_CKP parameter to logput, + * we'll get the record at LSN 1000. The checkpoint LSN there is 600. + * Now we have to scan backwards looking for a checkpoint before LSN 600. + * We find one at 500. This means that we can truncate the log before + * 500 or run recovery beginning at 500. + * + * Returns 0 if we find a suitable checkpoint or we retrieved the first + * record in the log from which to start. Returns DB_NOTFOUND if there + * are no log records, errno on error. + * + * PUBLIC: int CDB___log_findckp __P((DB_ENV *, DB_LSN *)); + */ +int +CDB___log_findckp(dbenv, lsnp) + DB_ENV *dbenv; + DB_LSN *lsnp; +{ + DBT data; + DB_LSN ckp_lsn, final_ckp, last_ckp, next_lsn; + __txn_ckp_args *ckp_args; + int ret; + + /* + * Need to find the appropriate point from which to begin + * recovery. + */ + memset(&data, 0, sizeof(data)); + if (F_ISSET(dbenv, DB_ENV_THREAD)) + F_SET(&data, DB_DBT_MALLOC); + ZERO_LSN(ckp_lsn); + if ((ret = CDB_log_get(dbenv, &last_ckp, &data, DB_CHECKPOINT)) != 0) { + if (ret == ENOENT) + goto get_first; + else + return (ret); + } + final_ckp = last_ckp; + + next_lsn = last_ckp; + do { + if (F_ISSET(dbenv, DB_ENV_THREAD)) + CDB___os_free(data.data, data.size); + + if ((ret = CDB_log_get(dbenv, &next_lsn, &data, DB_SET)) != 0) + return (ret); + if ((ret = CDB___txn_ckp_read(data.data, &ckp_args)) != 0) { + if (F_ISSET(dbenv, DB_ENV_THREAD)) + CDB___os_free(data.data, data.size); + return (ret); + } + if (IS_ZERO_LSN(ckp_lsn)) + ckp_lsn = ckp_args->ckp_lsn; + if (FLD_ISSET(dbenv->verbose, DB_VERB_CHKPOINT)) { + CDB___db_err(dbenv, "Checkpoint at: [%lu][%lu]", + (u_long)last_ckp.file, (u_long)last_ckp.offset); + CDB___db_err(dbenv, "Checkpoint LSN: [%lu][%lu]", + (u_long)ckp_args->ckp_lsn.file, + (u_long)ckp_args->ckp_lsn.offset); + CDB___db_err(dbenv, "Previous checkpoint: [%lu][%lu]", + (u_long)ckp_args->last_ckp.file, + (u_long)ckp_args->last_ckp.offset); + } + last_ckp = next_lsn; + next_lsn = ckp_args->last_ckp; + CDB___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) && + (CDB_log_compare(&last_ckp, &ckp_lsn) > 0 || + CDB_log_compare(&final_ckp, &last_ckp) == 0)); + + if (F_ISSET(dbenv, DB_ENV_THREAD)) + CDB___os_free(data.data, data.size); + + /* + * At this point, either, next_lsn is ZERO or ckp_lsn is the + * checkpoint lsn and last_ckp is the LSN of the last checkpoint + * before ckp_lsn. If the compare in the loop is still true, then + * next_lsn must be 0 and we need to roll forward from the + * beginning of the log. + */ + if (CDB_log_compare(&last_ckp, &ckp_lsn) >= 0 || + CDB_log_compare(&final_ckp, &last_ckp) == 0) { +get_first: if ((ret = CDB_log_get(dbenv, &last_ckp, &data, DB_FIRST)) != 0) + return (ret); + if (F_ISSET(dbenv, DB_ENV_THREAD)) + CDB___os_free(data.data, data.size); + } + *lsnp = last_ckp; + + return (IS_ZERO_LSN(last_ckp) ? DB_NOTFOUND : 0); +} |