POSTGRES(1) PostgreSQL Server Applications POSTGRES(1)NAMEpostgres - Run a PostgreSQL single-user backend
SYNOPSISpostgres [ -A { 0 | 1 } ] [ -B nbuffers ] [ -c name=value ] [ -d
debug-level ] [ -D datadir ] [ -e ] [ -E ] [ -f { s | i | t | n | m | h
} ] [ -F ] [ -i ] [ -L ] [ -N ] [ -o file-name ] [ -O ] [ -P ] [ -s |
-t { pa | pl | ex } ] [ -S sort-mem ] [ -W seconds ] 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 ] [ -L ] [ -o file-name ] [ -O ] [ -p database ] [ -P ] [ -s
| -t { pa | pl | ex } ] [ -S sort-mem ] [ -v protocol-version ] [ -W
seconds ]
DESCRIPTION
The postgres executable is the actual PostgreSQL server process that
processes queries. It is normally not called directly; instead a post‐
master(1) multi-user 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 mode. The primary use
for this mode is for bootstrapping by initdb(1).
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 inter-process communication and locking will
happen.
When running a stand-alone backend the session user name will automati‐
cally be set to the current effective Unix user name. If that user does
not exist the server will not start.
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, and -F have the same meaning as with
the postmaster(1).
-e Sets the default date style to ``European'', which means that
the ``day before month'' (rather than month before day) rule is
used to interpret ambiguous date input, and that the day is
printed before the month in certain date output formats. See the
PostgreSQL User's Guide for more information.
-o file-name
Sends all debugging and error output to OutputFile. If the
backend is running under the postmaster, error messages are
still sent to the frontend process as well as to OutputFile, but
debugging output is sent to the controlling tty of the postmas‐
ter (since only one file descriptor can be sent to an actual
file).
-P Ignore system indexes to scan/update system tuples. The 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.
-L Turns off the locking system.
-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
the -s option.
-v protocol
Specifies the version number of the frontend/backend protocol to
be used for this particular session.
-W seconds
As soon as this option is encountered, the process sleeps for
the specified amount of seconds. This gives developers time to
attach a debugger to the backend process.
SEE ALSOinitdb(1), ipcclean(1), postmaster(1)Application 2000-11-12 POSTGRES(1)