简要描述

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 thedatabase 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 logfile are written.-L   Log the execution of the db_checkpoint utility  to  the  specifiedfile in the following format, where ‘‘###’’ is the process ID, andthe date is the time the utility starting running.db_checkpoint: ### Wed Jun 15 01:23:45 EDT 1995This file will be  removed  if  the  db_checkpoint  utility  exitsgracefully.-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.  Inorder to avoid region corruption, it should always be given the  chanceto  detach  and  exit  gracefully.   To cause db_checkpoint to clean upafter itself and exit, send it an interrupt signal (SIGINT).The db_checkpoint utility exits 0  on  success,  and  >0  if  an  erroroccurs.

ENVIRONMENT VARIABLES

       The   following   environment   variables   affect   the  execution  ofdb_checkpoint:DB_HOMEIf the -h option is not specified  and  the  environment  variableDB_HOME  is  set,  it is used as the path of the database home, asdescribed in db_appinit(3).

SEE ALSO

       The DB library is a family of  groups  of  functions  that  provides  amodular  programming interface to transactions and record-oriented fileaccess.   The  library  includes  support  for  transactions,  locking,logging  and  file  page  caching,  as  well  as various indexed accessmethods.  Many of the functional groups (e.g., the  file  page  cachingfunctions)  are  useful independent of the other DB functions, althoughsome 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),

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:

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.