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@ -1,5 +1,5 @@ |
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<!-- |
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$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.57 2001/03/16 05:44:33 tgl Exp $ |
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$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.58 2001/03/24 00:24:26 tgl Exp $ |
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--> |
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<Chapter Id="runtime"> |
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@ -165,7 +165,7 @@ NOTICE: Initializing database with en_US collation order. |
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</para> |
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<para> |
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This shells syntax can get tedious quickly. Therefore the shell |
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This shell syntax can get tedious quickly. Therefore the shell |
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script wrapper <application>pg_ctl</application> is provided that |
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encapsulates some of the tasks. E.g., |
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<programlisting> |
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@ -266,10 +266,10 @@ su - postgres -c "/usr/local/pgsql/bin/pg_ctl start -l logfile -D /usr/local/pgs |
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</para> |
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<para> |
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While the <application>postmaster</application> is running, it's |
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While the <application>postmaster</application> is running, its |
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PID is in the file <filename>postmaster.pid</filename> in the data |
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directory. This is used as in interlock against multiple running |
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postmaster on the same data directory and can also be used for |
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directory. This is used as an interlock against multiple postmasters |
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running in the same data directory, and can also be used for |
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shutting down the postmaster. |
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</para> |
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@ -364,8 +364,9 @@ IpcSemaphoreCreate: semget(key=5440026, num=16, 01600) failed: No space left on |
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<para> |
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<screen> |
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connectDB() -- connect() failed: Connection refused |
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Is the postmaster running (with -i) at 'server.joe.com' and accepting connections on TCP/IP port 5432? |
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PQconnectPoll() -- connect() failed: Connection refused |
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Is the postmaster running (with -i) at 'server.joe.com' |
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and accepting connections on TCP/IP port 5432? |
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</screen> |
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This is the generic <quote>I couldn't find a server to talk |
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to</quote> failure. It looks like the above when TCP/IP |
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@ -378,8 +379,9 @@ Is the postmaster running (with -i) at 'server.joe.com' and accepting connection |
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Alternatively, you'll get this when attempting |
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Unix-socket communication to a local postmaster: |
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<screen> |
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connectDB() -- connect() failed: No such file or directory |
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Is the postmaster running locally and accepting connections on Unix socket '/tmp/.s.PGSQL.5432'? |
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connectDBstart() -- connect() failed: No such file or directory |
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Is the postmaster running locally |
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and accepting connections on Unix socket '/tmp/.s.PGSQL.5432'? |
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</screen> |
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</para> |
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@ -454,6 +456,8 @@ syslog = 2 |
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postmaster -c log_connections=yes -c syslog=2 |
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</programlisting> |
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which would have the same effect as the previous example. |
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Command-line options override any conflicting settings in |
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<filename>postgresql.conf</filename>. |
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</para> |
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<para> |
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@ -1066,7 +1070,9 @@ env PGOPTIONS='-c geqo=off' psql |
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that for a complex query, several sorts and/or hashes might be |
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running in parallel, and each one will be allowed to use as |
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much memory as this value specifies before it starts to put |
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data into temporary files. |
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data into temporary files. And don't forget that each running |
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backend could be doing one or more sorts. So the total memory |
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space needed could be many times the value of SORT_MEM. |
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</para> |
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</listitem> |
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</varlistentry> |
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@ -1396,7 +1402,7 @@ env PGOPTIONS='-c geqo=off' psql |
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not relevant for <productname>Postgres</>). Almost all modern |
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operating systems provide these features, but not all of them have |
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them turned on or sufficiently sized by default, especially |
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systems with BSD heritage. (For the QNX port, |
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systems with BSD heritage. (For the QNX and BeOS ports, |
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<productname>Postgres</> provides its own replacement |
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implementation of these facilities.) |
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</para> |
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@ -1510,7 +1516,7 @@ env PGOPTIONS='-c geqo=off' psql |
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estimate the required segment size as the number of buffers times |
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the block size (8192 kB by default) plus ample overhead (at least |
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half a megabyte). Any error message you might get will contain the |
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size of the failed allocation. |
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size of the failed allocation request. |
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</para> |
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<para> |
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@ -1533,7 +1539,7 @@ env PGOPTIONS='-c geqo=off' psql |
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is set by <varname>SEMMNS</>, which consequently must be at least |
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as high as the connection setting plus one extra for each 16 |
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allowed connections (see the formula in <xref |
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linkend="sysvipc-parameters">. The parameter <varname>SEMMNI</> |
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linkend="sysvipc-parameters">). The parameter <varname>SEMMNI</> |
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determines the limit on the number of semaphore sets that can |
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exist on the system at one time. Hence this parameter must be at |
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least <literal>ceil(max_connections / 16)</>. Lowering the number |
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@ -1588,7 +1594,7 @@ env PGOPTIONS='-c geqo=off' psql |
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#define SHMALL /* max amount of shared memory (pages) */ |
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</programlisting> |
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To increase the number of buffers supported by the postmaseter, add the |
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To increase the number of buffers supported by the postmaster, add the |
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following to your kernel config file. A <varname>SHMALL</> value of 1024 |
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represents 4MB of shared memory. Increase it accordingly: |
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<programlisting> |
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@ -1621,9 +1627,8 @@ options "SYSPTSIZE=13" |
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<title>Semaphores</> |
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<para> |
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You may need to increase the number of semaphores. By |
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default, <productname>Postgres</> allocates 32 semaphores, |
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one for each backend connection. This is just over half the |
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default system total of 60. |
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default, <productname>Postgres</> allocates 34 semaphores, |
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which is over half the default system total of 60. |
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</para> |
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</formalpara> |
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@ -1845,7 +1850,7 @@ set semsys:seminfo_semmsl=32 |
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counts but it can be changed by the user up to the hard limit. |
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The hard limit can only be changed by the root user. The system |
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call <function>setrlimit</function> is responsible for setting |
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these parameters. The shell the built-in command |
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these parameters. The shell's built-in command |
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<command>ulimit</command> (Bourne shells) or |
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<command>limit</command> (csh) is used to control the resource |
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limits from the command line. On BSD-derived systems the file |
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@ -1922,8 +1927,9 @@ default:\ |
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<listitem> |
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<para> |
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After receiving SIGTERM, the postmaster disallows new |
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connections but lets active backend end their work and shuts |
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down only after all of them terminated (by client request). |
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connections, but lets existing backends end their work normally. |
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It shuts down only after all of the backends terminate by client |
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request. |
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This is the <firstterm>Smart Shutdown</firstterm>. |
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</para> |
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</listitem> |
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@ -1933,10 +1939,11 @@ default:\ |
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<term>SIGINT</term> |
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<listitem> |
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<para> |
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The postmaster disallows new connections, sends all active |
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backends SIGTERM (which will cause them to abort immediately), |
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waits for children to exit and shuts down the data base. This |
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is the <firstterm>Fast Shutdown</firstterm>. |
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The postmaster disallows new connections and sends all existing |
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backends SIGTERM, which will cause them to abort their current |
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transactions and exit promptly. It then waits for the backends to exit |
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and finally shuts down the data base. |
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This is the <firstterm>Fast Shutdown</firstterm>. |
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</para> |
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</listitem> |
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</varlistentry> |
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@ -1948,8 +1955,9 @@ default:\ |
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This is the <firstterm>Immediate Shutdown</firstterm> which |
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will cause the postmaster to send a SIGQUIT to all backends and |
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exit immediately (without properly shutting down the database |
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system). When WAL is implemented, this will lead to recovery on |
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start-up. Right now it's not recommendable to use this option. |
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system). The backends likewise exit immediately upon receiving |
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SIGQUIT. This will lead to recovery (by replaying the WAL log) |
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upon next start-up. This is recommended only in emergencies. |
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</para> |
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</listitem> |
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</varlistentry> |
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@ -1957,10 +1965,9 @@ default:\ |
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<caution> |
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<para> |
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If at all possible, do not use SIGKILL to shut down the |
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postmaster. This can cause data corruption and will prevent the |
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cleaning up of shared memory resources, which you will have to |
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do yourself in that case. |
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It is best not to use SIGKILL to shut down the postmaster. This |
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will prevent the postmaster from releasing shared memory and |
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semaphores, which you may then have to do by hand. |
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</para> |
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</caution> |
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@ -1969,12 +1976,13 @@ default:\ |
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<filename>postmaster.pid</filename> in the data directory. So for |
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example, to do a fast shutdown: |
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<screen> |
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> <userinput>kill -INT `cat /usr/local/pgsql/data/postmaster.pid`</userinput> |
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> <userinput>kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`</userinput> |
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</screen> |
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</para> |
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<para> |
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The program <application>pg_ctl</application> is a shell script |
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wrapper that provides a convenient interface to these functions. |
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that provides a more convenient interface for shutting down the |
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postmaster. |
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</para> |
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</sect1> |
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Tom Lane
25 years ago