SYNOPSIS
postgres [ -A 0 | 1 ] [ -B nbuffers ] [ -c name=value ] [ -d debug-
level ] [ -D datadir ] [ -e ] [ -E ] [ -f s | i | t | n | m | h ] [ -F
] [ -i ] [ -N ] [ -o filename ] [ -O ] [ -P ] [ -s | -t pa | pl | ex ]
[ -S sort-mem ] [ -W seconds ] [ --name=value ] database
postgres [ -A 0 | 1 ] [ -B nbuffers ] [ -c name=value ] [ -d debug-
level ] [ -D datadir ] [ -e ] [ -f s | i | t | n | m | h ] [ -F ] [ -i
] [ -o filename ] [ -O ] [ -p database ] [ -P ] [ -s | -t pa | pl | ex
] [ -S sort-mem ] [ -v protocol-version ] [ -W seconds ] [ --name=value
]
DESCRIPTION
The postgres executable is the actual PostgreSQL server process that
processes queries. It is normally not called directly; instead a post-
master(1) multiuser server is started.
The second form above is how postgres is invoked by the postmaster(1)
(only conceptually, since both postmaster and postgres are in fact the
same program); it should not be invoked directly this way. The first
form invokes the server directly in interactive single-user mode. The
primary use for this mode is during bootstrapping by initdb(1). Some-
times it is used for debugging or disaster recovery.
When invoked in interactive mode from the shell, the user can enter
queries and the results will be printed to the screen, but in a form
that is more useful for developers than end users. But note that run-
ning a single-user backend is not truly suitable for debugging the
server since no realistic interprocess communication and locking will
happen.
When running a stand-alone backend, the session user will be set to the
user with ID 1. This user does not actually have to exist, so a stand-
alone backend can be used to manually recover from certain kinds of
accidental damage to the system catalogs. Implicit superuser powers are
granted to the user with ID 1 in stand-alone mode.
OPTIONS
When postgres is started by a postmaster(1) then it inherits all
options set by the latter. Additionally, postgres-specific options can
be passed from the postmaster with the -o switch.
You can avoid having to type these options by setting up a configura-
tion file. See the Administrator’s Guide for details. Some (safe)
options can also be set from the connecting client in an application-
dependent way. For example, if the environment variable PGOPTIONS is
set, then libpq-based clients will pass that string to the server,
which will interpret it as postgres command-line options.
GENERAL PURPOSE
The options -A, -B, -c, -d, -D, -F, and --name have the same meanings
as the postmaster(1) except that -d 0 prevents the debugging level of
the postmaster from being propagated to the backend.
-e Sets the default date style to ‘‘European’’, which means that
the ‘‘day before month’’ (rather than month before day) rule is
REINDEX command for system tables/indexes requires this option
to be used.
-s Print time information and other statistics at the end of each
query. This is useful for benchmarking or for use in tuning the
number of buffers.
-S sort-mem
Specifies the amount of memory to be used by internal sorts and
hashes before resorting to temporary disk files. The value is
specified in kilobytes, and defaults to 512 kilobytes. Note that
for a complex query, several sorts and/or hashes might be run-
ning in parallel, and each one will be allowed to use as much as
sort-mem kilobytes before it starts to put data into temporary
files.
OPTIONS FOR STAND-ALONE MODE
database
Specifies the name of the database to be accessed. If it is
omitted it defaults to the user name.
-E Echo all queries.
-N Disables use of newline as a query delimiter.
SEMI-INTERNAL OPTIONS
There are several other options that may be specified, used mainly for
debugging purposes. These are listed here only for the use by Post-
greSQL system developers. Use of any of these options is highly dis-
couraged. Furthermore, any of these options may disappear or change in
a future release without notice.
-f { s | i | m | n | h }
Forbids the use of particular scan and join methods: s and i
disable sequential and index scans respectively, while n, m, and
h disable nested-loop, merge and hash joins respectively.
Note: Neither sequential scans nor nested-loop joins can be dis-
abled completely; the -fs and -fn options simply discourage the
optimizer from using those plan types if it has any other alter-
native.
-i Prevents query execution, but shows the plan tree.
-O Allows the structure of system tables to be modified. This is
used by initdb.
-p database
Indicates that this server has been started by a postmaster and
makes different assumptions about buffer pool management, file
descriptors, etc.
-t pa[rser] | pl[anner] | e[xecutor]
Print timing statistics for each query relating to each of the
major system modules. This option cannot be used together with
ENVIRONMENT
PGDATA Default data direction location
For others, which have little influence during single-user mode, see
postmaster(1).
NOTES
To stop a running query use the SIGINT signal. To tell postgres to
reread the config file, use a SIGHUP signal. The postmaster uses
SIGTERM to tell a postgres process to quit normally and SIGQUIT to ter-
minate without the normal cleanup. These should not be used by users.
USAGE
Start a stand-alone backend with a command like
postgres -D $PGDATA other-options my_database
Provide the correct path to the database area with -D, or make sure
that the environment variable PGDATA is set. Also specify the name of
the particular database you want to work in.
Normally, the stand-alone backend treats newline as the command entry
terminator; there is no intelligence about semicolons, as there is in
psql. To continue a command across multiple lines, you must type back-
slash just before each newline except the last one.
But if you use the -N command line switch, then newline does not termi-
nate command entry. The backend will read the standard input until the
end-of-file (EOF) marker, then process the input as a single query
string. Backslash-newline is not treated specially in this case.
To quit the session, type EOF (Control+D, usually). If you’ve used -N,
two consecutive EOFs are needed to exit.
Note that the stand-alone backend does not provide sophisticated line-
editing features (no command history, for example).
SEE ALSO
initdb(1), ipcclean(1), postmaster(1)
Application 2002-11-22 POSTGRES(1)
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