DB5.3_DEADLOCK(1)

💖 DB5.3_DEADLOCK 💖

okay bestie, we're doing the db5.3_deadlock page from the General Commands Manual — and no, it's not about your group chat when nobody will text back first. it's about actual, real, honest-to-god deadlocks in a Berkeley DB environment. let's get into it 💅

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✨ NAME ✨

db5.3_deadlock — detect and abort deadlocks 🔥

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🎀 SYNOPSIS 🎀

db5.3_deadlock [-Vv] [-a e | m | n | o | W | w | y] [-h home] [-L file]
[-t sec.usec]

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🦋 DESCRIPTION 🦋

so here's the vibe. the db5.3_deadlock utility traverses the database environment lock region, and every single time it spots a deadlock — or a lock request that's timed out — it aborts a lock request. and by default? when it's a deadlock situation, it just picks a random lock request to abort. chaos but make it efficient ✨

now listen. this utility should be run as a background daemon, OR the underlying Berkeley DB deadlock detection interfaces should be called some other way, whenever you've got multiple threads or processes hitting a database and at least one of them is modifying it. literally do not skip this step, fr fr 😭

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🌸 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 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 db5.3_deadlock utility exits gracefully. so don't go looking for it after a clean shutdown, bestie 🫶

• -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. 👀

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if the -t option is not specified, db5.3_deadlock will run once and exit. one and done, no loitering 💀

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). and babes, in order to avoid environment corruption when you're using a Berkeley 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 resources and exit cleanly, send it an interrupt signal (SIGINT). that's your little "okay bye, love u" signal 😭

⚠️ the db5.3_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 db5.3_deadlock utility should be started. order matters, periodt. 👑

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.

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🌈 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.

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💜 AUTHORS 💜

Sleepycat Software, Inc. this manual page was created based on the HTML documentation for db_deadlock from Sleepycat, by Thijs Kinkhorst <thijs@kinkhorst.com>, for the Debian system (but may be used by others). iconic of them, honestly 🎀

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and that's the whole page, bestie!! this one came from the 28 January 2005 era of the DB5.3_DEADLOCK(1) manual — old school, but the lock detection still eats. mwah 💖✨