mirror of https://github.com/postgres/postgres
Thomas G. Lockhart
27 years ago
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.\" This is -*-nroff-*- |
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.\" XXX standard disclaimer belongs here.... |
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.\" $Header: /cvsroot/pgsql/doc/src/sgml/ref/postgres-ref.sgml,v 1.1 1999/05/26 17:25:38 thomas Exp $ |
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.TH POSTGRESQL UNIX 05/19/99 PostgreSQL PostgreSQL |
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.SH NAME |
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postgres - the Postgres backend server |
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.SH SYNOPSIS |
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.BR "postgres" |
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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 "-C" |
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] |
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[\c |
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.BR "-D" |
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data_directory] |
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[\c |
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.BR "-E" |
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] |
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[\c |
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.BR "-F" |
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] |
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[\c |
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.BR "-O" |
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] |
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[\c |
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.BR "-Q" |
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] |
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[\c |
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.BR "-S kbytes" |
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] |
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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 "-e" |
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] |
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[\c |
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.BR "-o" |
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output_file] |
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[\c |
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.BR "-s" |
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] |
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[\c |
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.BR "-v protocol" |
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] |
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[dbname] |
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.in -5n |
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.SH DESCRIPTION |
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The Postgres backend server can be executed directly from the user shell. |
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This should be done only while debugging by the DBA, and should not be |
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done while other Postgres backends are being managed by a |
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.IR postmaster |
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on this set of databases. |
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.PP |
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Some of the switches explained in this man page can be passed to the backend |
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through the "database options" field of a connection request, and thus can be |
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set for a particular backend without going to the trouble of restarting the |
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postmaster. This is particularly handy for debugging-related switches. |
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.PP |
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The optional argument |
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.IR dbname |
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specifies the name of the database to be accessed. |
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.IR Dbname |
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defaults to the value of the |
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.SM USER |
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environment variable. |
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.PP |
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The |
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.IR postgres |
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server understands the following command-line options: |
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.TP |
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.BR "-B" " n_buffers" |
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If the backend is running under the |
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.IR postmaster , |
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.IR "n_buffers" |
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is the number of shared-memory buffers that the |
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.IR "postmaster" |
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has allocated for the backend server processes that it starts. If the |
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backend is running standalone, this specifies the number of buffers to |
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allocate. This value defaults to 64 buffers, where each buffer is 8k bytes |
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(or whatever BLCKSZ is set to in config.h). |
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.TP |
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.BR "-C" |
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Do not show server version number. |
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.TP |
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.BR "-D" " data_directory" |
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This option specifies the pathname of the directory that contains the |
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database system data (the tables, the catalogs, etc.). If you don't |
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specify this option, Postgres uses the value of the PGDATA environment |
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variable. You must either specify a -D option or set PGDATA. |
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|
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The data directory pathname for a database system is normally determined when |
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the database system is created with |
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.IR initdb , |
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with a --pgdata option to |
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.IR initdb . |
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.TP |
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.BR "-E" |
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Echo all queries. |
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.TP |
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.BR "-F" |
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Disable automatic fsync() call after each transaction. |
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This option improves performance, but an operating system crash |
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while a transaction is in progress will probably cause data loss. |
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.TP |
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.BR "-O" |
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Override restrictions, so system table structures can be modified(pg_*). |
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.TP |
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.BR "-Q" |
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Specifies \*(lqquiet\*(rq mode. |
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.TP |
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.BR "-S" " kbytes" |
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Specifies the amount of memory to be used by internal sorts and hashes |
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before resorting to temporary disk files. The value is specified in |
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kilobytes, and defaults to 512 kilobytes. Note that for a complex query, |
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several sorts and/or hashes might be running in parallel, and each one |
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will be allowed to use as much as -S kilobytes before it starts to put |
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data into temporary files. |
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.TP |
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.BR "-e" |
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The |
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.IR "-e" |
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option controls how dates are input to and output from the database. |
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.IP |
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If the |
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.IR "-e" |
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option is supplied, then all dates passed to and from the frontend |
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processes will be assumed to be in |
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.IR "European" |
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format ie. |
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.IR "DD-MM-YYYY" |
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otherwise dates are input and output in |
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.IR "American" |
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format ie. |
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.IR "MM-DD-YYYY" |
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.TP |
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.BR "-d" " debug_level" |
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Turns on debugging at the numeric level |
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.IR "debug_level" . |
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Turning on debugging will cause query, parse trees, and query plans to |
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be displayed. |
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.TP |
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.BR "-o" " output_file" |
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Sends all debugging and error output to |
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.IR output_file . |
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If the backend is running under the |
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.IR postmaster , |
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error messages are still sent to the frontend process as well as to |
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.IR output_file , |
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but debugging output is sent to the controlling tty of the |
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.IR postmaster |
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(since only one file descriptor can be sent to an actual file). |
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.TP |
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.BR "-s" |
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Print time information and other statistics at the end of each query. |
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This is useful for benchmarking or for use in tuning the number of |
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buffers. |
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.TP |
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.BR "-v" " protocol" |
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Specifies the number of the frontend/backend protocol to be used for this |
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particular session. |
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.SH "DEVELOPER COMMAND OPTIONS" |
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There are several other options that may be specified, used mainly |
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for debugging purposes. These are listed here only for the use by |
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Postgres system developers. |
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.BR "Use of any of these options is highly discouraged" . |
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Furthermore, any of these options may disappear or change at any time. |
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.TP |
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.BR "-A" "n|r|b|Q\fIn\fP|X\fIn\fP" |
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.IP |
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This option generates a tremendous amount of output. |
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.TP |
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.BR "-L" |
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Turns off the locking system. |
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.TP |
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.BR "-N" |
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Disables use of newline as a query delimiter. |
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.TP |
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.BR "-f" |
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Forbids the use of particular scan and join methods: |
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.IR s " and " i |
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disable sequential and index scans respectively, while |
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.IR n ", " m " and " h |
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disable nested-loop, merge and hash joins respectively. |
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(Neither sequential scans nor nested-loop joins can be disabled completely; |
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the -fs and -fn options simply discourage the optimizer from using those |
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plan types if it has any other alternative.) |
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.TP |
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.BR "-i" |
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Prevents query execution, but shows the plan tree. |
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.TP |
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.BR "-p" " databasename" |
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Indicates to the backend server that it has been started by a |
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.IR postmaster |
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and make different assumptions about buffer pool management, file |
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descriptors, etc. Switches following -p are restricted to those |
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considered "secure". |
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.TP |
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.BR "-t" "pa[rser]|pl[anner]|e[xecutor]" |
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Print timing statistics for each query relating to each of the major |
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system modules. This option cannot be used with |
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.BR "-s" . |
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.SH "SEE ALSO" |
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ipcclean(1), |
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psql(1), |
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postmaster(1). |
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.SH "DIAGNOSTICS" |
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Of the nigh-infinite number of error messages you may see when you |
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execute the backend server directly, the most common will probably be: |
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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 |
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.IR postgres |
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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. |
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@ -0,0 +1,500 @@ |
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<refentry id="APP-POSTMASTER"> |
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<refmeta> |
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<refentrytitle> |
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<application>postmaster</application> |
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</refentrytitle> |
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<refmiscinfo>Application</refmiscinfo> |
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</refmeta> |
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<refnamediv> |
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<refname id="postmaster"> |
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<application>postmaster</application> |
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</refname> |
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<refpurpose> |
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Run the <productname>Postgres</productname> multi-user backend |
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</refpurpose> |
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</refnamediv> |
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<refsynopsisdiv> |
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<refsynopsisdivinfo> |
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<date>1999-05-19</date> |
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</refsynopsisdivinfo> |
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<synopsis> |
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postmaster [ -B <replaceable class="parameter">nBuffers</replaceable> ] |
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[ -D <replaceable class="parameter">DataDir</replaceable> ] [-N <replaceable class="parameter">nBackends</replaceable> ] [ -S ] |
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[ -d [ <replaceable class="parameter">DebugLevel</replaceable> ] ] |
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[ -i ] [ -o <replaceable class="parameter">BackendOptions</replaceable> ] [ -p <replaceable class="parameter">port</replaceable> ] |
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postmaster [ -n | -s ] ... |
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</synopsis> |
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|
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<refsect2 id="R2-APP-POSTMASTER-1"> |
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<refsect2info> |
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<date>1999-05-19</date> |
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</refsect2info> |
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<title> |
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Inputs |
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</title> |
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<para> |
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<application>postmaster</application> accepts the following command line arguments: |
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|
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<variablelist> |
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<varlistentry> |
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<term> |
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-B <replaceable class="parameter">nBuffers</replaceable> |
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</term> |
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<listitem> |
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<para> |
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The number of shared-memory buffers for the |
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<application>postmaster</application> |
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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 buffers, where each buffer is 8k bytes |
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(or whatever BLCKSZ is set to in config.h). |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-D <replaceable class="parameter">DataDir</replaceable> |
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</term> |
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<listitem> |
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<para> |
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Specifies the directory to use as the root of the tree of database |
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directories. If -D is not given, the default data directory name is |
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the value of the environment variable |
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<envar>PGDATA</envar>. |
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If <envar>PGDATA</envar> is not set, then the directory used is |
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<filename>$POSTGRESHOME/data</filename>. |
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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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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-N <replaceable class="parameter">nBackends</replaceable> |
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</term> |
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<listitem> |
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<para> |
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The maximum number of backend server processes that this postmaster |
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is allowed to start. In the default configuration, this value |
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is usually set |
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to 32, and can be set as high as 1024 if your system will support that |
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many processes. Both the default and upper limit values can be altered |
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when building <productname>Postgres</productname> (see src/include/config.h). |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-S |
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</term> |
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<listitem> |
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<para> |
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Specifies that the <application>postmaster</application> |
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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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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-d [ <replaceable class="parameter">DebugLevel</replaceable> ] |
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</term> |
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<listitem> |
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<para> |
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The optional argument <replaceable class="parameter">DebugLevel</replaceable> |
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determines the amount of debugging output the backend servers will |
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produce. |
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If <replaceable class="parameter">DebugLevel</replaceable> |
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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 <application>postmaster</application>. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-i |
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</term> |
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<listitem> |
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<para> |
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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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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-o <replaceable class="parameter">BackendOptions</replaceable> |
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</term> |
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<listitem> |
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<para> |
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|
The |
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<literal>postgres</literal> |
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|
options specified in |
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<replaceable class="parameter">BackendOptions</replaceable> |
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|
are passed to all backend server processes started by this |
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<application>postmaster</application>. |
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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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</para> |
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</listitem> |
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</varlistentry> |
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|
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<varlistentry> |
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<term> |
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-p <replaceable class="parameter">port</replaceable> |
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|
</term> |
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<listitem> |
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<para> |
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|
Specifies the TCP/IP port or local Unix domain socket file extension |
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on which the <application>postmaster</application> |
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is to listen for connections from frontend applications. Defaults to |
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the value of the |
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<envar>PGPORT</envar> |
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environment variable, or if <envar>PGPORT</envar> |
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is not set, then defaults to the value established when Postgres was |
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compiled (normally 5432). If you specify a port other than the |
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default port then all frontend applications (including |
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<application>psql</application>) must specify the same |
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port using either command-line options or |
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<envar>PGPORT</envar>. |
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</para> |
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</listitem> |
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</varlistentry> |
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|
</variablelist> |
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|
</para> |
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|
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<para> |
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A few command line options are available for debugging in the case |
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when a backend dies abnormally. |
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|
These options control the behavior of the |
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|
<application>postmaster</application> in this situation, and |
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<emphasis>neither option is intended for use in |
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ordinary operation</emphasis>. |
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|
</para> |
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|
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<para> |
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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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|
</para> |
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|
|
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|
<para> |
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|
These special-case options are: |
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|
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|
<variablelist> |
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|
<varlistentry> |
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|
<term> |
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|
-n |
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|
</term> |
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|
<listitem> |
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|
<para> |
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|
If the <literal>-n</literal> |
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|
option is supplied, then the |
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|
<application>postmaster</application> |
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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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|
<application>shmemdoc</application> |
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|
program to examine shared memory and semaphore state. |
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|
</para> |
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|
</listitem> |
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|
</varlistentry> |
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|
|
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|
<varlistentry> |
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|
<term> |
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|
-s |
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|
</term> |
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|
<listitem> |
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|
<para> |
||||||
|
<application>postmaster</application> |
||||||
|
will stop all other backend processes by sending the signal |
||||||
|
<literal>SIGSTOP</literal>, |
||||||
|
but will not cause them to terminate. This permits system programmers |
||||||
|
to collect core dumps from all backend processes by hand. |
||||||
|
</para> |
||||||
|
</listitem> |
||||||
|
</varlistentry> |
||||||
|
</variablelist> |
||||||
|
</para> |
||||||
|
</refsect2> |
||||||
|
|
||||||
|
<refsect2 id="R2-APP-POSTMASTER-1"> |
||||||
|
<refsect2info> |
||||||
|
<date>1999-05-19</date> |
||||||
|
</refsect2info> |
||||||
|
<title> |
||||||
|
Outputs |
||||||
|
</title> |
||||||
|
<para> |
||||||
|
|
||||||
|
<variablelist> |
||||||
|
<!-- |
||||||
|
<varlistentry> |
||||||
|
<term> |
||||||
|
FindBackend: could not find a backend to execute... |
||||||
|
</term> |
||||||
|
<listitem> |
||||||
|
<para> |
||||||
|
If you see this message, you do not have the |
||||||
|
<application>postgres</application> |
||||||
|
executable in your path. Add the directory in which |
||||||
|
<application>postgres</application> resides to |
||||||
|
your path. |
||||||
|
</para> |
||||||
|
</listitem> |
||||||
|
</varlistentry> |
||||||
|
--> |
||||||
|
<varlistentry> |
||||||
|
<term> |
||||||
|
semget: No space left on device |
||||||
|
</term> |
||||||
|
<listitem> |
||||||
|
<para> |
||||||
|
If you see this message, you should run the |
||||||
|
<application>ipcclean</application> |
||||||
|
command. After doing this, try starting |
||||||
|
<application>postmaster</application> |
||||||
|
again. If this still doesn't work, you probably need to configure |
||||||
|
your kernel for shared memory and semaphores as described in the |
||||||
|
installation notes. If you run multiple instances of |
||||||
|
<application>postmaster</application> |
||||||
|
on a single host, or have a kernel with particularly small shared memory |
||||||
|
and/or semaphore limits, you may have to reconfigure your kernel to increase |
||||||
|
its shared memory or semaphore parameters. |
||||||
|
|
||||||
|
<tip> |
||||||
|
<para> |
||||||
|
You may be able to postpone |
||||||
|
reconfiguring your kernel by decreasing -B to reduce |
||||||
|
<productname>Postgres</productname>' shared memory |
||||||
|
consumption, or by reducing -N to reduce Postgres' semaphore |
||||||
|
consumption. |
||||||
|
</para> |
||||||
|
</tip> |
||||||
|
</para> |
||||||
|
</listitem> |
||||||
|
</varlistentry> |
||||||
|
|
||||||
|
<varlistentry> |
||||||
|
<term> |
||||||
|
StreamServerPort: cannot bind to port |
||||||
|
</term> |
||||||
|
<listitem> |
||||||
|
<para> |
||||||
|
If you see this message, you should be certain that there is no other |
||||||
|
<application>postmaster</application> |
||||||
|
process already running. The easiest way to determine this is by |
||||||
|
using the command |
||||||
|
<programlisting> |
||||||
|
% ps -ax | grep postmaster |
||||||
|
</programlisting> |
||||||
|
on BSD-based systems, or |
||||||
|
<programlisting> |
||||||
|
% ps -e | grep postmast |
||||||
|
</programlisting> |
||||||
|
for System V-like or POSIX-compliant systems such as HP-UX. |
||||||
|
</para> |
||||||
|
|
||||||
|
<para> |
||||||
|
If you |
||||||
|
are sure that no other |
||||||
|
<application>postmaster</application> |
||||||
|
processes are running and you still get this error, try specifying a |
||||||
|
different port using the |
||||||
|
<literal>-p</literal> |
||||||
|
option. You may also get this error if you terminate the |
||||||
|
<application>postmaster</application> |
||||||
|
and immediately restart it using the same port; in this case, you must |
||||||
|
simply wait a few seconds until the operating system closes the port |
||||||
|
before trying again. Finally, you may get this error if you specify |
||||||
|
a port number that your operating system considers to be reserved. |
||||||
|
For example, many versions of Unix consider port numbers under 1024 to |
||||||
|
be <firstterm>trusted</firstterm> |
||||||
|
and only permit the Unix superuser to access them. |
||||||
|
</para> |
||||||
|
</listitem> |
||||||
|
</varlistentry> |
||||||
|
|
||||||
|
<varlistentry> |
||||||
|
<term> |
||||||
|
IpcMemoryAttach: shmat() failed: Permission denied |
||||||
|
</term> |
||||||
|
<listitem> |
||||||
|
<para> |
||||||
|
A likely explanation is that another user attempted to start a |
||||||
|
<application>postmaster</application> |
||||||
|
process on the same port which acquired shared resources and then |
||||||
|
died. Since Postgres shared memory keys are based on the port number |
||||||
|
assigned to the |
||||||
|
<application>postmaster</application>, |
||||||
|
such conflicts are likely if there is more than one installation on |
||||||
|
a single host. If there are no other |
||||||
|
<application>postmaster</application> |
||||||
|
processes currently running (see above), run |
||||||
|
<application>ipcclean</application> |
||||||
|
and try again. If other <application>postmaster</application> |
||||||
|
images |
||||||
|
are running, you will have to find the owners of those processes to |
||||||
|
coordinate the assignment of port numbers and/or removal of unused |
||||||
|
shared memory segments. |
||||||
|
</para> |
||||||
|
</listitem> |
||||||
|
</varlistentry> |
||||||
|
</variablelist> |
||||||
|
</para> |
||||||
|
</refsect2> |
||||||
|
</refsynopsisdiv> |
||||||
|
|
||||||
|
<refsect1 id="R1-APP-POSTMASTER-1"> |
||||||
|
<refsect1info> |
||||||
|
<date>1999-05-19</date> |
||||||
|
</refsect1info> |
||||||
|
<title> |
||||||
|
Description |
||||||
|
</title> |
||||||
|
|
||||||
|
<para> |
||||||
|
<application>postmaster</application> |
||||||
|
manages the communication between frontend and backend processes, as |
||||||
|
well as allocating the shared buffer pool and SysV semaphores |
||||||
|
(on machines without a test-and-set instruction). |
||||||
|
<application>postmaster</application> |
||||||
|
does not itself interact with the user and should be started as a |
||||||
|
background process. |
||||||
|
</para> |
||||||
|
|
||||||
|
<para> |
||||||
|
<emphasis>Only one postmaster should be running at a time in a given |
||||||
|
<productname>Postgres</productname> installation.</emphasis> |
||||||
|
Here, an installation means a database directory and |
||||||
|
<application>postmaster</application> port number. |
||||||
|
You can run more than one postmaster on a machine only if each one has a |
||||||
|
separate directory and port number. |
||||||
|
</para> |
||||||
|
|
||||||
|
<refsect1 id="R1-APP-VACUUMDB-2"> |
||||||
|
<refsect1info> |
||||||
|
<date>1998-10-04</date> |
||||||
|
</refsect1info> |
||||||
|
<title> |
||||||
|
Notes |
||||||
|
</title> |
||||||
|
|
||||||
|
<para> |
||||||
|
If at all possible, |
||||||
|
<emphasis>do not</emphasis> |
||||||
|
use <literal>SIGKILL</literal> |
||||||
|
when killing the <application>postmaster</application>. |
||||||
|
<literal>SIGHUP</literal>, |
||||||
|
<literal>SIGINT</literal>, |
||||||
|
or |
||||||
|
<literal>SIGTERM</literal> |
||||||
|
(the default signal for |
||||||
|
<application>kill</application>(1))" |
||||||
|
should be used instead. Using |
||||||
|
|
||||||
|
<programlisting> |
||||||
|
% kill -KILL |
||||||
|
</programlisting> |
||||||
|
|
||||||
|
or its alternative form |
||||||
|
|
||||||
|
<programlisting> |
||||||
|
% kill -9 |
||||||
|
</programlisting> |
||||||
|
|
||||||
|
will prevent <application>postmaster</application> |
||||||
|
from freeing the system resources (e.g., shared memory and semaphores) |
||||||
|
that it holds before dying. This prevents you from having to deal with |
||||||
|
the problem with shared memory described earlier. |
||||||
|
</para> |
||||||
|
|
||||||
|
<para> |
||||||
|
Useful utilities for dealing with shared memory problems include |
||||||
|
<application>ipcs(1)</application>, |
||||||
|
<application>ipcrm(1</application>), and |
||||||
|
<application>ipcclean(1)</application>. |
||||||
|
</para> |
||||||
|
</refsect1> |
||||||
|
|
||||||
|
<refsect1 id="R1-APP-VACUUMDB-3"> |
||||||
|
<refsect1info> |
||||||
|
<date>1998-10-04</date> |
||||||
|
</refsect1info> |
||||||
|
<title> |
||||||
|
Usage |
||||||
|
</title> |
||||||
|
<para> |
||||||
|
To start <application>postmaster</application> using default |
||||||
|
values, type: |
||||||
|
|
||||||
|
<programlisting> |
||||||
|
% nohup postmaster >logfile 2>&1 & |
||||||
|
</programlisting> |
||||||
|
|
||||||
|
This command will start up <application>postmaster</application> |
||||||
|
on the default port (5432). This is the |
||||||
|
simplest and most common way to start the |
||||||
|
<application>postmaster</application>. |
||||||
|
</para> |
||||||
|
|
||||||
|
<para> |
||||||
|
To start <application>postmaster</application> with a specific port |
||||||
|
and executable name: |
||||||
|
|
||||||
|
<programlisting> |
||||||
|
% nohup postmaster -p 1234 & |
||||||
|
</programlisting> |
||||||
|
|
||||||
|
This command will start up <application>postmaster</application> |
||||||
|
communicating through the port 1234. In order to |
||||||
|
connect to this <application>postmaster</application> |
||||||
|
using psql, you would need to run it as |
||||||
|
|
||||||
|
<programlisting> |
||||||
|
% psql -p 1234 |
||||||
|
</programlisting> |
||||||
|
|
||||||
|
or set the environment variable <envar>PGPORT</envar>: |
||||||
|
|
||||||
|
<programlisting> |
||||||
|
% setenv PGPORT 1234 |
||||||
|
% psql |
||||||
|
</programlisting>. |
||||||
|
|
||||||
|
</refsect1> |
||||||
|
</refentry> |
||||||
|
|
||||||
|
<!-- Keep this comment at the end of the file |
||||||
|
Local variables: |
||||||
|
mode: sgml |
||||||
|
sgml-omittag:nil |
||||||
|
sgml-shorttag:t |
||||||
|
sgml-minimize-attributes:nil |
||||||
|
sgml-always-quote-attributes:t |
||||||
|
sgml-indent-step:1 |
||||||
|
sgml-indent-data:t |
||||||
|
sgml-parent-document:nil |
||||||
|
sgml-default-dtd-file:"../reference.ced" |
||||||
|
sgml-exposed-tags:nil |
||||||
|
sgml-local-catalogs:"/usr/lib/sgml/catalog" |
||||||
|
sgml-local-ecat-files:nil |
||||||
|
End: |
||||||
|
--> |
||||||
Loading…
Reference in new issue