db_checkpoint(1) [mojave man page]
db_checkpoint(1) BSD General Commands Manual db_checkpoint(1) NAME
db_checkpoint SYNOPSIS
db_checkpoint [-1Vv] [-h home] [-k kbytes] [-L file] [-P password] [-p min] DESCRIPTION
The db_checkpoint utility is a daemon process that monitors the database log, and periodically calls DB_ENV->txn_checkpoint to checkpoint it. The options are as follows: -1 Checkpoint the log once, regardless of whether or not there has been activity since the last checkpoint and then exit. -h Specify a home directory for the database environment; by default, the current working directory is used. -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 was started. db_checkpoint: ### Wed Jun 15 01:23:45 EDT 1995 This file will be removed if the db_checkpoint utility exits gracefully. -P 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. -p Checkpoint the database at least every min minutes if there has been any activity since the last checkpoint. -V Write the library version number to the standard output, and exit. -v Write the time of each checkpoint attempt to the standard output. At least one of the -1, -k, and -p options must be specified. The db_checkpoint 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 envi- ronment, db_checkpoint should always be given the chance to detach from the environment and exit gracefully. To cause db_checkpoint to release all environment resources and exit cleanly, send it an interrupt signal (SIGINT). The db_checkpoint utility does not attempt to create the Berkeley DB shared memory regions if they do not already exist. The application that creates the region should be started first, and once the region is created, the db_checkpoint utility should be started. The DB_ENV->txn_checkpoint method is the underlying method used by the db_checkpoint utility. See the db_checkpoint utility source code for an example of using DB_ENV->txn_checkpoint in a IEEE/ANSI Std 1003.1 (POSIX) environment. The db_checkpoint utility exits 0 on success, and >0 if an error occurs. ENVIRONMENT
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_ENV->open. SEE ALSO
db_archive(1), db_deadlock(1), db_dump(1), db_load(1), db_printlog(1), db_recover(1), db_stat(1), db_upgrade(1), db_verify(1) Darwin December 3, 2003 Darwin
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db_deadlock(1) BSD General Commands Manual db_deadlock(1) NAME
db_deadlock SYNOPSIS
db_deadlock [-Vv] [-a e | m | n | o | w | y] [-h home] [-L file] [-t sec.usec] DESCRIPTION
The db_deadlock utility traverses the database environment lock region, and aborts a lock request each time it detects a deadlock or a lock request that has timed out. By default, in the case of a deadlock, a random lock request is chosen to be aborted. This utility should be run as a background daemon, or the underlying Berkeley DB deadlock detection interfaces should be called in some other way, whenever there are multiple threads or processes accessing a database and at least one of them is modifying it. The options are as follows: -a When a deadlock is detected, abort the locker: m with the greatest number of locks n with the fewest number of locks o with the oldest locker ID w with the fewest number of write locks y with the youngest locker ID When lock or transaction timeouts have been specified: e abort any lock request that has timed out -h Specify a home directory for the database environment; by default, the current working directory is used. -L Log the execution of the db_deadlock utility to the specified file in the following format, where ### is the process ID, and the date is the time the utility was started. db_deadlock: ### Wed Jun 15 01:23:45 EDT 1995 This file will be removed if the db_deadlock utility exits gracefully. -t Check the database environment every sec seconds plus usec microseconds to see if a process has been forced to wait for a lock; if one has, review the database environment lock structures. -V Write the library version number to the standard output, and exit. -v Run in verbose mode, generating messages each time the detector runs. If the -t option is not specified, db_deadlock will run once and exit. The db_deadlock 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 envi- ronment, db_deadlock should always be given the chance to detach from the environment and exit gracefully. To cause db_deadlock to release all environment resources and exit cleanly, send it an interrupt signal (SIGINT). The db_deadlock utility does not attempt to create the Berkeley DB shared memory regions if they do not already exist. The application which creates the region should be started first, and then, once the region is created, the db_deadlock utility should be started. The DB_ENV->lock_detect method is the underlying method used by the db_deadlock utility. See the db_deadlock utility source code for an exam- ple of using DB_ENV->lock_detect in a IEEE/ANSI Std 1003.1 (POSIX) environment. The db_deadlock utility exits 0 on success, and >0 if an error occurs. ENVIRONMENT
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_ENV->open. SEE ALSO
db_archive(1), db_checkpoint(1), db_dump(1), db_load(1), db_printlog(1), db_recover(1), db_stat(1), db_upgrade(1), db_verify(1) Darwin December 3, 2003 Darwin