listen_addresses
(string
)
Specifies the TCP/IP address(es) on which the server is
to listen for connections from client applications.
The value takes the form of a comma-separated list of host names
and/or numeric IP addresses. The special entry *
corresponds to all available IP interfaces.
If the list is empty, the server does not listen on any IP interface
at all, in which case only Unix-domain sockets can be used to connect
to it.
The default value is localhost,
which allows only local “loopback” connections to be made.
This parameter can only be set at server start.
port
(integer
)
The TCP port the server listens on; 5432 by default. Note that the same port number is used for all IP addresses the server listens on. This parameter can only be set at server start.
max_connections
(integer
)
Determines the maximum number of concurrent connections to the database server. The default is typically 100 connections, but may be less if your kernel settings will not support it (as determined during initdb). This parameter can only be set at server start.
Increasing this parameter may cause PostgreSQL to request more System V shared memory or semaphores than your operating system's default configuration allows. See Section 16.4.1, “Shared Memory and Semaphores” for information on how to adjust those parameters, if necessary.
superuser_reserved_connections
(integer
)
Determines the number of connection “slots” that
are reserved for connections by PostgreSQL
superusers. At most max_connections
connections can ever be active simultaneously. Whenever the
number of active concurrent connections is at least
max_connections
minus
superuser_reserved_connections
, new
connections will be accepted only for superusers.
The default value is three connections. The value must be less
than the value of max_connections
. This
parameter can only be set at server start.
unix_socket_directory
(string
)
Specifies the directory of the Unix-domain socket on which the
server is to listen for
connections from client applications. The default is normally
/tmp
, but can be changed at build time.
This parameter can only be set at server start.
unix_socket_group
(string
)
Sets the owning group of the Unix-domain socket. (The owning
user of the socket is always the user that starts the
server.) In combination with the parameter
unix_socket_permissions
this can be used as
an additional access control mechanism for Unix-domain connections.
By default this is the empty string, which selects the default
group for the current user. This parameter can only be set at
server start.
unix_socket_permissions
(integer
)
Sets the access permissions of the Unix-domain socket. Unix-domain
sockets use the usual Unix file system permission set.
The parameter value is expected to be a numeric mode
specification in the form accepted by the
chmod
and umask
system calls. (To use the customary octal format the number
must start with a 0
(zero).)
The default permissions are 0777
, meaning
anyone can connect. Reasonable alternatives are
0770
(only user and group, see also
unix_socket_group
) and 0700
(only user). (Note that for a Unix-domain socket, only write
permission matters and so there is no point in setting or revoking
read or execute permissions.)
This access control mechanism is independent of the one described in Chapter 20, Client Authentication.
This parameter can only be set at server start.
bonjour_name
(string
)
Specifies the Bonjour broadcast
name. The computer name is used if this parameter is set to the
empty string ''
(which is the default). This parameter is
ignored if the server was not compiled with
Bonjour support.
This parameter can only be set at server start.
tcp_keepalives_idle
(integer
)
On systems that support the TCP_KEEPIDLE
socket option, specifies the
number of seconds between sending keepalives on an otherwise idle
connection. A value of zero uses the system default. If TCP_KEEPIDLE
is
not supported, this parameter must be zero. This parameter is ignored for
connections made via a Unix-domain socket.
tcp_keepalives_interval
(integer
)
On systems that support the TCP_KEEPINTVL
socket option, specifies how
long, in seconds, to wait for a response to a keepalive before
retransmitting. A value of zero uses the system default. If TCP_KEEPINTVL
is not supported, this parameter must be zero. This parameter is ignored
for connections made via a Unix-domain socket.
tcp_keepalives_count
(integer
)
On systems that support the TCP_KEEPCNT
socket option, specifies how
many keepalives may be lost before the connection is considered dead.
A value of zero uses the system default. If TCP_KEEPCNT
is not
supported, this parameter must be zero. This parameter is ignored
for connections made via a Unix-domain socket.
authentication_timeout
(integer
)
Maximum time to complete client authentication, in seconds. If a
would-be client has not completed the authentication protocol in
this much time, the server breaks the connection. This prevents
hung clients from occupying a connection indefinitely.
The default is one minute (1m
).
This parameter can only be set in the postgresql.conf
file or on the server command line.
ssl
(boolean
)
Enables SSL connections. Please read
Section 16.7, “Secure TCP/IP Connections with SSL” before using this. The default
is off
. This parameter can only be set at server
start.
password_encryption
(boolean
)
When a password is specified in CREATE USER or
ALTER USER
without writing either ENCRYPTED
or
UNENCRYPTED
, this parameter determines whether the
password is to be encrypted. The default is on
(encrypt the password).
krb_server_keyfile
(string
)
Sets the location of the Kerberos server key file. See Section 20.2.3, “Kerberos authentication” for details. This parameter can only be set at server start.
krb_srvname
(string
)
Sets the Kerberos service name. See Section 20.2.3, “Kerberos authentication” for details. This parameter can only be set at server start.
krb_server_hostname
(string
)
Sets the host name part of the service principal.
This, combined with krb_srvname
, is used to generate
the complete service principal, that is
krb_srvname
/
krb_server_hostname
@
REALM.
If not set, the default is the server host name. See Section 20.2.3, “Kerberos authentication”
for details. This parameter can only be set at server start.
krb_caseins_users
(boolean
)
Sets whether Kerberos user names should be treated case-insensitively.
The default is off
(case sensitive). This parameter
can only be set at server start.
db_user_namespace
(boolean
)
This parameter enables per-database user names. It is off by default.
This parameter can only be set in the postgresql.conf
file or on the server command line.
If this is on, you should create users as username@dbname
.
When username
is passed by a connecting client,
@
and the database name are appended to the user
name and that database-specific user name is looked up by the
server. Note that when you create users with names containing
@
within the SQL environment, you will need to
quote the user name.
With this parameter enabled, you can still create ordinary global
users. Simply append @
when specifying the user
name in the client. The @
will be stripped off
before the user name is looked up by the server.
This feature is intended as a temporary measure until a complete solution is found. At that time, this option will be removed.