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d5bbe2aca5
I've completed the patch to fix the protocol and authentication issues I was discussing a couple of weeks ago. The particular changes are: - the protocol has a version number - network byte order is used throughout - the pg_hba.conf file is used to specify what method is used to authenticate a frontend (either password, ident, trust, reject, krb4 or krb5) - support for multiplexed backends is removed - appropriate changes to man pages - the -a switch to many programs to specify an authentication service no longer has any effect - the libpq.so version number has changed to 1.1 The new backend still supports the old protocol so old interfaces won't break.
336 lines
9.1 KiB
Groff
336 lines
9.1 KiB
Groff
.\" This is -*-nroff-*-
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.\" XXX standard disclaimer belongs here....
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.\" $Header: /cvsroot/pgsql/src/man/Attic/postmaster.1,v 1.11 1998/01/26 01:42:52 scrappy Exp $
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.TH POSTMASTER UNIX 11/05/95 PostgreSQL PostgreSQL
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.SH "NAME"
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postmaster - run the Postgres postmaster
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.SH "SYNOPSIS"
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.BR "postmaster"
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[\c
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.BR "-B"
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n_buffers]
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[\c
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.BR "-D"
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data_dir]
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[\c
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.BR "-S" \c
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]
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[\c
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.BR "-a"
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system]
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.br
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.in +5n
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[\c
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.BR "-b"
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backend_pathname]
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[\c
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.BR "-d"
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[debug_level]]
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[\c
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.BR "-i" \c
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]
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[\c
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.BR "-n" \c
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]
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.br
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[\c
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.BR "-o"
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backend_options]
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[\c
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.BR "-p"
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port]
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[\c
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.BR "-s" \c
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]
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.in -5n
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.SH "DESCRIPTION"
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The
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.IR "postmaster"
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manages the communication between frontend and backend processes, as
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well as allocating the shared buffer pool and semaphores (on machines
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without a test-and-set instruction). The
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.IR postmaster
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does not itself interact with the user and should be started as a
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background process.
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.BR "Only one postmaster should be run on a machine."
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.PP
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The
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.IR "postmaster"
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understands the following command-line options:
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.TP 5n
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.BR "-B" " n_buffers"
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.IR "n_buffers"
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is the number of shared-memory buffers for the
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.IR "postmaster"
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to allocate and manage for the backend server processes that it
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starts. This value defaults to 64, and each buffer is 8k bytes.
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.TP
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.BR "-D" " data_dir"
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Specifies the directory to use as the root of the tree of database
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directories. This directory uses the value of the environment
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variable
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.SM PGDATA.
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If
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.SM PGDATA
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is not set, then the directory used is
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.SM $POSTGRESHOME\c
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/data. If neither environment variable is set and this command-line
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option is not specified, the default directory that was
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set at compile-time is used.
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.TP
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.BR "-S"
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Specifies that the
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.IR "postmaster"
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process should start up in silent mode. That is, it will disassociate
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from the user's (controlling) tty and start its own process group.
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This should not be used in combination with debugging options because
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any messages printed to standard output and standard error are
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discarded.
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.TP
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.BR "-a" " system"
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Specifies whether or not to use the authentication system
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.IR "system"
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(see
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.IR pgintro (1))
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for frontend applications to use in connecting to the
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.IR postmaster
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process. Specify
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.IR "system"
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to enable a system, or
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.BI "no" "system"
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to disable a system. For example, to permit users to use
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.IR Kerberos
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authentication, use
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.BR "-a kerberos" ;
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to deny any unauthenticated
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connections, use
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.BR "-a nounauth .
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This option no longer has any effect.
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.TP
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.BR "-b" " backend_pathname"
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.IR "backend_pathname"
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is the full pathname of the Postgres backend server executable file that
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the
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.IR "postmaster"
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will invoke when it receives a connection from a frontend application.
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If this option is not used, then the
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.IR postmaster
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tries to find this executable file in the directory in which its own
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executable is located (this is done by looking at the pathname under
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which the
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.IR "postmaster"
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was invoked. If no pathname was specified, then the
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.SM PATH
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environment variable is searched for an executable named
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\*(lqpostgres\*(rq).
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.TP
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.BR "-d" " [debug_level]"
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The optional argument
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.IR debug_level
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determines the amount of debugging output the backend servers will
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produce.
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If
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.I debug_level
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is one, the postmaster will trace all connection traffic,
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and nothing else.
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For levels two and higher,
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debugging is turned on in the backend process and the postmaster
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displays more information,
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including the backend environment and process traffic.
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Note that if no file is specified for backend servers to
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send their debugging output then this output will appear on the
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controlling tty of their parent
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.IR postmaster .
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.TP
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.BR "-i"
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This enables TCP/IP or Internet domain socket communication.
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Without this option, only local Unix domain socket communication is
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possible.
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.TP
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.BR "-n" ", " "-s"
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The
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.IR "-s" " and " "-n"
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options control the behavior of the
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.IR "postmaster"
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when a backend dies abnormally. \fBNeither option is intended for use in
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ordinary operation\fP.
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.IP
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The ordinary strategy for this situation is to notify all other
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backends that they must terminate and then reinitialize the shared
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memory and semaphores. This is because an errant backend could have
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corrupted some shared state before terminating.
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.IP
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If the
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.IR "-s"
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option is supplied, then the
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.IR "postmaster"
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will stop all other backend processes by sending the signal
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.SM SIGSTOP,
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but will not cause them to terminate. This permits system programmers
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to collect core dumps from all backend processes by hand.
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.IP
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If the
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.IR "-n"
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option is supplied, then the
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.IR "postmaster"
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does not reinitialize shared data structures. A knowledgable system
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programmer can then use the
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.IR shmemdoc
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program to examine shared memory and semaphore state.
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.TP
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.BR "-o" " backend_options"
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The
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.IR postgres (1)
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options specified in
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.IR "backend_options"
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are passed to all backend server processes started by this
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.IR postmaster .
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If the option string contains any spaces, the entire string must be
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quoted.
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.TP
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.BR "-p" " port"
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Specifies the TCP/IP port or local Unix domain socket file extension
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on which the
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.IR postmaster
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is to listen for connections from frontend applications. Defaults to
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5432, or the value of the
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.SM PGPORT
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environment variable (if set). If you specify a port other than the
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default port then all frontend application users must specify the same
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port (using command-line options or
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.SM PGPORT\c
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) when starting any libpq application, including psql.
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.SH "WARNINGS"
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If at all possible,
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.BR "do not"
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use
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.SM SIGKILL
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when killing the
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.IR "postmaster" "."
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.SM SIGHUP,
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.SM SIGINT,
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or
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.SM SIGTERM
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(the default signal for
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.IR "kill" "(1))"
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should be used instead. Hence, avoid
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.nf
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kill -KILL
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.fi
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or its alternative form
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.nf
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kill -9
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.fi
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as this will prevent the
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.IR postmaster
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from freeing the system resources (e.g., shared memory and semaphores)
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that it holds before dying. This prevents you from having to deal with
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the problem with
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.IR shmat (2)
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described below.
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.SH "EXAMPLES"
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.nf
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# start postmaster using default values
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nohup postmaster >logfile 2>&1 &
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.fi
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This command will start up
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.IR "postmaster"
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on the default port (5432) and will search
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.SM $PATH
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to find an executable file called \*(lqpostgres\*(rq. This is the
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simplest and most common way to start the
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.IR "postmaster" .
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.nf
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# start with specific port and executable name
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nohup postmaster -p -b /usr/postgres/bin/postgres &
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.fi
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This command will start up a
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.IR "postmaster"
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communicating through the port 1234, and will attempt to use the
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backend located at \*(lq/usr/postgres/bin/postgres\*(rq. In order to
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connect to this
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.IR "postmaster"
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using psql, you would need to either
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specify
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.BR "-p 1234"
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on the
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.IR "psql"
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command-line or set the environment variable
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.SM PGPORT
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to 1234.
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.SH "SEE ALSO"
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ipcs(1),
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ipcrm(1),
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ipcclean(1),
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psql(1),
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postgres(1),
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.SH "DIAGNOSTICS"
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.TP
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.BR "FindBackend: could not find a backend to execute..."
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If you see this message, you do not have the
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.IR "postgres"
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executable in your path. Add the directoy in which postgres resides to
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your path.
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.TP
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.BR "semget: No space left on device"
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If you see this message, you should run the
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.IR "ipcclean"
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command. After doing this, try starting the
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.IR "postmaster"
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again. If this still doesn't work, you probably need to configure
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your kernel for shared memory and semaphores as described in the
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installation notes. If you run multiple
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.IR postmaster s
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on a single host, or have reduced the shared memory and semaphore
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parameters from the defaults in the generic kernel, you may have to
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go back and increase the shared memory and semaphores configured
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into your kernel.
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.TP
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.BR "StreamServerPort: cannot bind to port"
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If you see this message, you should be certain that there is no other
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.IR "postmaster"
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process already running. The easiest way to determine this is by
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using the command
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.nf
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ps -ax | grep postmaster
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.fi
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on BSD-based systems
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.nf
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ps -e | grep postmast
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.fi
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(the equivalent syntax is on System V-like or POSIX-compliant systems such as HP-UX). If you
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are sure that no other
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.IR "postmaster"
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processes are running and you still get this error, try specifying a
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different port using the
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.BR "-p"
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option. You may also get this error if you terminate the
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.IR "postmaster"
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and immediately restart it using the same port; in this case, you must
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simply wait a few seconds until the operating system closes the port
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before trying again. Finally, you may get this error if you specify
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a port number that your operating system considers to be reserved.
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For example, many versions of Unix consider port numbers under 1024 to
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be \*(lqtrusted\*(rq and only permit the Unix superuser to access them.
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.TP
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.BR "IpcMemoryAttach: shmat() failed: Permission denied"
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A likely explanation is that another user attempted to start a
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.IR "postmaster"
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process on the same port which acquired shared resources and then
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died. Since Postgres shared memory keys are based on the port number
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assigned to the
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.IR "postmaster" ,
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such conflicts are likely if there is more than one installation on
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a single host. If there are no other
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.IR "postmaster"
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processes currently running (see above), run
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.IR "ipcclean"
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and try again. If other
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.IR "postmaster" s
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are running, you will have to find the owners of those processes to
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coordinate the assignment of port numbers and/or removal of unused
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shared memory segments.
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