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DB5.3_DEADLOCK(1) General Commands Manual DB5.3_DEADLOCK(1)
NAME
db5.3_deadlock - Detect and abort deadlocks
SYNOPSIS
db5.3_deadlock [-Vv] [-a e | m | n | o | W | w | y] [-h home] [-L file] [-t sec.usec]
DESCRIPTION
The db5.3_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 de-
fault, 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.
OPTIONS
-a When a deadlock is detected, abort the locker:
m with the most locks
n with the fewest locks
o with the oldest lock
W with the most write locks
w with the fewest write locks
y with the youngest lock
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 db5.3_deadlock utility to the specified file in the fol-
lowing 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 db5.3_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 en-
vironment 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, db5.3_deadlock will run once and exit.
The db5.3_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 Berke-
ley DB environment, db5.3_deadlock should always be given the chance to detach from the
environment and exit gracefully. To cause db5.3_deadlock to release all environment re-
sources and exit cleanly, send it an interrupt signal (SIGINT).
The db5.3_deadlock utility does not attempt to create the Berkeley DB shared memory re-
gions if they do not already exist. The application which creates the region should be
started first, and then, once the region is created, the db5.3_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 example of using DB_ENV->lock_detect in a
IEEE/ANSI Std 1003.1 (POSIX) environment.
The db5.3_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.
AUTHORS
Sleepycat Software, Inc. This manual page was created based on the HTML documentation for
db_deadlock from Sleepycat, by Thijs Kinkhorst <thijs AT kinkhorst.com>, for the Debian sys-
tem (but may be used by others).
28 January 2005 DB5.3_DEADLOCK(1)
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