DB_ENV->log_verify()

#include <db.h>
int
DB_ENV->log_verify(DB_ENV *dbenv, const DB_LOG_VERIFY_CONFIG *config); 
    

The DB_ENV->log_verify() method verifies the integrity of the log records of an environment and writes both error and normal messages to the error/message output facility of the database environment handle.

The DB_ENV->log_verify() method does not perform the locking function, even in Berkeley DB environments that are configured with a locking subsystem. Because this function does not access any database files, you can call it even when the environment has other threads of control attached and running.

The DB_ENV->log_verify() method is the underlying method used by the DB_ENV-> db_log_verify utility. See the DB_ENV-> db_log_verify utility source code for an example of using DB_ENV->log_verify() in a IEEE/ANSI Std 1003.1 (POSIX) environment.

The DB_ENV->log_verify() method returns DB_LOG_VERIFY_BAD when either log errors are detected or the internal data storage layer does not work. It returns EINVAL if you specify wrong configurations. Unless otherwise specified, the DB_ENV->log_verify() method returns a non-zero error value on failure and 0 on success.

Parameters

config

The configuration parameter of type DB_LOG_VERIFY_CONFIG is for the verification of log files. A struct variable of this type must be memset to 0 before setting any configurations to it.

DB_LOG_VERIFY_CONFIG members

struct __db_logvrfy_config {
int continue_after_fail, verbose;
u_int32_t cachesize;
const char *temp_envhome;
const char *dbfile, *dbname;
DB_LSN start_lsn, end_lsn;
time_t start_time, end_time;
};

continue_after_fail

The continue_after_fail parameter specifies whether or not continue the verification process when an error in the log is detected.

verbose

The verbose parameter specifies whether or not to display verbose output during the verification process.

cachesize

The cachesize parameter specifies the size of the cache of the temporary internal environment in bytes.

temp_envhome

The temp_envhome parameter is the home directory of the temporary database environment that is used internally during the verification. It can be NULL, meaning the environment and all databases are in-memory.

dbfile

The dbfile parameter specifies that for log records involving a database file, only those related to this database file are verified. Log records not involving database files are verified regardless of this parameter.

dbname

The dbname parameter specifies that for log records involving a database file, only those related to this database file are verified. Log records not involving database files are verified regardless of this parameter.

start_lsn and end_lsn

The start_lsn and end_lsn parameters specify the range of log records from the entire log set, that must be verified. Either of them can be [0][0], to specify an open ended range. If both of them are [0][0] (by default) the entire log is verified.

start_time and end_time

The start_time and end_time parameters specify range of log records from the entire log set that must be verified for a time range. Either of them can be 0, to specify an open ended range. If both of them are 0 (by default), the entire log is verified.

Note that the time range specified is not precise, because such a time range is converted to an lsn range based on the time points we know from transaction commits and checkpoints.

You can specify either an lsn range or a time range. You can neither specify both nor specify an lsn and a time as a range.

Environment Variables

If the database is opened within a database environment, the environment variable DB_HOME can be used as the path of the database environment home.

Errors

The DB_ENV->log_verify() method may fail and return one of the following non-zero errors:

EINVAL or DB_LOG_VERIFY_BAD.

Class

DB_ENV

See Also

Database Environments and Related Methods