IPCCLEAN(1) PostgreSQL Server Applications IPCCLEAN(1)NAME
ipcclean - remove shared memory and semaphores from an aborted PostgreSQL server
SYNOPSIS
ipcclean
DESCRIPTION
ipcclean removes all shared memory segments and semaphore sets owned by the current user. It is intended to be used for cleaning up after a
crashed PostgreSQL server (postmaster(1)). Note that immediately restarting the server will also clean up shared memory and semaphores, so
this command is of little real utility.
Only the database administrator should execute this program as it can cause bizarre behavior (i.e., crashes) if run during multiuser execu-
tion. If this command is executed while a postmaster is running, the shared memory and semaphores allocated by the postmaster will be
deleted. This will result in a general failure of the backend servers started by that postmaster.
NOTES
This script is a hack, but in the many years since it was written, no one has come up with an equally effective and portable solution.
Since the postmaster can now clean up by itself, it is unlikely that ipcclean will be improved upon in the future.
The script makes assumption about the format of output of the ipcs utility which may not be true across different operating systems.
Therefore, it may not work on your particular OS.
Application 2002-11-22 IPCCLEAN(1)
Check Out this Related Man Page
IPCS(1) BSD General Commands Manual IPCS(1)NAME
ipcs -- report System V interprocess communication facilities status
SYNOPSIS
ipcs [-abcMmopQqSsTt]
DESCRIPTION
The ipcs utility provides information on System V interprocess communication (IPC) facilities on the system.
The options are as follows:
-a Show the maximum amount of information possible when displaying active semaphores, message queues, and shared memory segments. (This
is shorthand for specifying the -b, -c, -o, -p, and -t options.)
-b Show the maximum allowed sizes for active semaphores, message queues, and shared memory segments. The ``maximum allowed size'' is
the maximum number of bytes in a message on a message queue, the size of a shared memory segment, or the number of semaphores in a
set of semaphores.
-c Show the creator's name and group for active semaphores, message queues, and shared memory segments.
-M Display system information about shared memory.
-m Display information about active shared memory segments.
-o Show outstanding usage for active message queues, and shared memory segments. The ``outstanding usage'' is the number of messages in
a message queue, or the number of processes attached to a shared memory segment.
-p Show the process ID information for active semaphores, message queues, and shared memory segments. The ``process ID information'' is
the last process to send a message to or receive a message from a message queue, the process that created a semaphore, or the last
process to attach or detach a shared memory segment.
-Q Display system information about messages queues.
-q Display information about active message queues.
-S Display system information about semaphores.
-s Display information about active semaphores.
-T Display system information about shared memory, message queues and semaphores.
-t Show access times for active semaphores, message queues, and shared memory segments. The access times is the time of the last con-
trol operation on an IPC object, the last send or receive of a message, the last attach or detach of a shared memory segment, or the
last operation on a semaphore.
If none of the -M, -m, -Q, -q, -S, or -s options are specified, information about all active IPC facilities is listed.
RESTRICTIONS
System data structures may change while ipcs is running; the output of ipcs is not guaranteed to be consistent.
BUGS
This manual page is woefully incomplete, because it does not at all attempt to explain the information printed by ipcs.
SEE ALSO ipcrm(1)AUTHORS
Thorsten Lockert <tholo@sigmasoft.com>
BSD June 18, 1994 BSD