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db_deadlock(1) [osx man page]

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

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db_stat(1)						    BSD General Commands Manual 						db_stat(1)

NAME
db_stat SYNOPSIS
db_stat -d file [-fN] [-h home] [-P password] [-s database] db_stat [-celmNrtVZ] [-C Aclmop] [-h home] [-M Ahm] [-P password] DESCRIPTION
The db_stat utility utility displays statistics for Berkeley DB environments. The options are as follows: -C Display internal information about the lock region. (The output from this option is often both voluminous and meaningless, and is intended only for debugging.) A Display all information. c Display lock conflict matrix. l Display lockers within hash chains. m Display region memory information. o Display objects within hash chains. p Display lock region parameters. -c Display lock region statistics, as described in DB_ENV->lock_stat. -d Display database statistics for the specified file, as described in DB->stat. If the database contains multiple databases and the -s flag is not specified, the statistics are for the internal database that describes the other databases the file contains, and not for the file as a whole. -e Display current environment statistics. -f Display only those database statistics that can be acquired without traversing the database. -h Specify a home directory for the database environment; by default, the current working directory is used. -l Display log region statistics, as described in DB_ENV->log_stat. -M Display internal information about the shared memory buffer pool. (The output from this option is often both voluminous and meaningless, and is intended only for debugging.) A Display all information. h Display buffers within hash chains. m Display region memory information. -m Display shared memory buffer pool statistics, as described in DB_ENV->memp_stat. -N Do not acquire shared region mutexes while running. Other problems, such as potentially fatal errors in Berkeley DB, will be ignored as well. This option is intended only for debugging errors, and should not be used under any other circumstances. -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. -r Display replication statistics, as described in DB_ENV->rep_stat. -s Display statistics for the specified database contained in the file specified with the -d flag. -t Display transaction region statistics, as described in DB_ENV->txn_stat. -V Write the library version number to the standard output, and exit. -Z Reset the statistics after reporting them; valid only with the -c, -e, -l, -m, and -t options. Values normally displayed in quantities of bytes are displayed as a combination of gigabytes (GB), megabytes (MB), kilobytes (KB), and bytes (B). Otherwise, values smaller than 10 million are displayed without any special notation, and values larger than 10 million are displayed as a number followed by "M". The db_stat utility may be used with 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_stat should always be given the chance to detach from the environment and exit gracefully. To cause db_stat to release all environment resources and exit cleanly, send it an interrupt signal (SIGINT). The db_stat 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_deadlock(1), db_dump(1), db_load(1), db_printlog(1), db_recover(1), db_upgrade(1), db_verify(1) Darwin December 3, 2003 Darwin
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