Berkeley DB 的内容
安装的程序： db_archive, db_checkpoint, db_deadlock, db_dump, db_hotbackup, db_load, db_printlog, db_recover, db_stat, db_upgrade, db_verify
简要描述
| db_archive | 打印出不再使用的日志文件路径名 |
| db_checkpoint | 监视和检查数据库日志的守护进程 |
| db_deadlock | 当死锁发生时，退出锁定要求 |
| db_dump | 把数据库文件转换成 db_load 能认出的文本文件 |
| db_hotbackup | 创建 "hot backup" 或者是 "hot failover" 的 Berkeley DB 数据库镜像。 |
| db_load | 从db_dump产生的文本文件中创建出数据库文件 |
| db_printlog | 把数据库日志文件转换成人能读懂的文本 |
| db_recover | 在发生错误后，把数据库恢复到一致的状态 |
| db_stat | 显示数据库环境统计 |
| db_upgrade | 把数据库文件转换成新版本的Berkley DB格式 |
| db_verify | 对数据库文件进行一致性检查 |
| libdb.{so,a} | 包含db处理相关函数的C库 |
| libdb_cxx.{so,a} | 包含db处理相关函数的C++库 |
NAME
db_checkpoint - the DB database checkpoint utility
SYNOPSIS
db_checkpoint [-1v] [-h home] [-k kbytes] [-L file] [-p min]
DESCRIPTION
The db_checkpoint utility is a daemon process that monitors the
database log and periodically calls txn_checkpoint(3) to checkpoint it.
The options are as follows:
-1 Checkpoint the log once, and then exit.
-h Specify a home directory for the database.
-k Checkpoint the database at least as often as every kbytes of log
file are written.
-L Log the execution of the db_checkpoint utility to the specified
file in the following format, where ‘‘###’’ is the process ID, and
the date is the time the utility starting running.
db_checkpoint: ### Wed Jun 15 01:23:45 EDT 1995
This file will be removed if the db_checkpoint utility exits
gracefully.
-p Checkpoint the database at least every min minutes.
-v Write the time of each checkpoint to the standard output.
At least one of the -1, -k and -p options must be specified.
The db_checkpoint utility attaches to DB shared memory regions. In
order to avoid region corruption, it should always be given the chance
to detach and exit gracefully. To cause db_checkpoint to clean up
after itself and exit, send it an interrupt signal (SIGINT).
The db_checkpoint utility exits 0 on success, and >0 if an error
occurs.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of
db_checkpoint:
DB_HOME
If the -h option is not specified and the environment variable
DB_HOME is set, it is used as the path of the database home, as
described in db_appinit(3).
SEE ALSO
The DB library is a family of groups of functions that provides a
modular programming interface to transactions and record-oriented file
access. The library includes support for transactions, locking,
logging and file page caching, as well as various indexed access
methods. Many of the functional groups (e.g., the file page caching
functions) are useful independent of the other DB functions, although
some functional groups are explicitly based on other functional groups
(e.g., transactions and logging).
db_archive(1), db_checkpoint(1), db_deadlock(1), db_dump(1),
db_load(1), db_recover(1), db_stat(1),
d db_archive
db_archive [-adlsVv] [-h home] [-P password]
实用程序打印不再使用的日志文件路径名(例如,不再参与活动事务),到标准输出,每行一个路径名。应该将这些日志文件备份到媒体上为数据库崩溃提供恢复(还需要数据库的快照文件),但他们可能会被删除从系统回收磁盘空间。
The db_archive utility writes the pathnames of log files that are no longer in use (for example, no longer involved in active transactions), to the standard output, one pathname per line. These log files should be written to backup media to provide for recovery in the case of catastrophic failure (which also requires a snapshot of the database files), but they may then be deleted from the system to reclaim disk space.
The options are as follows:
-
-a 绝对路径
Write all pathnames as absolute pathnames, instead of relative to the database home directory.
-
-d 删除不再需要的日志文件,删除后数据崩溃时将不可恢复.
Remove log files that are no longer needed; no filenames are written. This automatic log file removal is likely to make catastrophic recovery impossible.
-
-h
Specify a home directory for the database environment; by default, the current working directory is used.
-
-l 列出所有日志文件,包括正在使用的.
Write out the pathnames of all the database log files, whether or not they are involved in active transactions.
-
-P 指定密码
Specify an environment password. Although Berkeley DB utilities overwrite password strings as soon as possible, be aware there may be a window of vulnerability on systems where unprivileged users can see command-line arguments or where utilities are not able to overwrite the memory containing the command-line arguments.
-
-s
Write the pathnames of all the database files that need to be archived in order to recover the database from catastrophic failure. If any of the database files have not been accessed during the lifetime of the current log files, db_archive will not include them in this output.
It is possible that some of the files to which the log refers have since been deleted from the system. In this case, db_archive will ignore them. Whendb_recover is run, any files to which the log refers that are not present during recovery are assumed to have been deleted and will not be recovered.
-
-V
Write the library version number to the standard output, and exit.
-
-v
Run in verbose mode.
Log cursor handles (returned by the DB_ENV->log_cursor() method) may have open file descriptors for log files in the database environment. Also, the Berkeley DB interfaces to the database environment logging subsystem (for example, DB_ENV->log_put() and DB_TXN->abort() may allocate log cursors and have open file descriptors for log files as well. On operating systems where filesystem related system calls (for example, rename and unlink on Windows/NT) can fail if a process has an open file descriptor for the affected file, attempting to move or remove the log files listed by db_archive may fail. All Berkeley DB internal use of log cursors operates on active log files only and furthermore, is short-lived in nature. So, an application seeing such a failure should be restructured to close any open log cursors it may have, and otherwise to retry the operation until it succeeds. (Although the latter is not likely to be necessary; it is hard to imagine a reason to move or rename a log file in which transactions are being logged or aborted.)
The db_archive utility uses a Berkeley DB environment (as described for the -h option, the environment variable DB_HOME, or because the utility was run in a directory containing a Berkeley DB environment). In order to avoid environment corruption when using a Berkeley DB environment, db_archive should always be given the chance to detach from the environment and exit gracefully. To cause db_archive to release all environment resources and exit cleanly, send it an interrupt signal (SIGINT).
The DB_ENV->log_archive() method is the underlying method used by the db_archive utility. See the db_archive utility source code for an example of using DB_ENV->log_archive() in an IEEE/ANSI Std 1003.1 (POSIX) environment.
The db_archive utility exits 0 on success, and >0 if an error occurs.
Environment Variables
DB_HOME
If the -h option is not specified and the environment variable DB_HOME is set, it is used as the path of the database home, as described in the DB_ENV->open()method.