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From: Josh Kupershmidt <[email protected]>
To: pgsql-docs <[email protected]>
Subject: Out of date advice about SIGTERM'ing backends
Date: Fri, 29 Jun 2012 20:10:40 -0700
Message-ID: <CAK3UJRHHVHSLewwwXzKcvhKoXagxR07j=2U4P9hGqPmA=oJ1Kg@mail.gmail.com> (raw)

Hi all,

In the "Notes" section[0] of the postgres command's page, this advice is given:

| The postgres server uses SIGTERM to tell subordinate server
| processes to quit normally and SIGQUIT to terminate without
| the normal cleanup. These signals should not be used by users.

I think now that we've added pg_terminate_backend() and made it
callable by non-superusers, we should relax the caveat against using
SIGTERM against backends. The warning to stay away from using SIGQUIT
seems fine as-is. Patch attached.

Josh

[0] http://www.postgresql.org/docs/9.2/static/app-postgres.html#AEN87192


Attachments:

  [application/octet-stream] backends_sigterm.diff (1.8K, 2-backends_sigterm.diff)
  download | inline diff:
diff --git a/doc/src/sgml/ref/postgres-ref.sgml b/doc/src/sgml/ref/postgres-ref.sgml
new file mode 100644
index 4e5cd02..a1d014d
*** a/doc/src/sgml/ref/postgres-ref.sgml
--- b/doc/src/sgml/ref/postgres-ref.sgml
*************** PostgreSQL documentation
*** 726,739 ****
  
    <para>
     To cancel a running query, send the <literal>SIGINT</literal> signal
!    to the process running that command.
    </para>
  
    <para>
!    The <command>postgres</command> server uses <literal>SIGTERM</literal>
!    to tell subordinate server processes to quit normally and
!    <literal>SIGQUIT</literal> to terminate without the normal cleanup.
!    These signals <emphasis>should not</emphasis> be used by users.  It
     is also unwise to send <literal>SIGKILL</literal> to a server
     process &mdash; the main <command>postgres</command> process will
     interpret this as a crash and will force all the sibling processes
--- 726,743 ----
  
    <para>
     To cancel a running query, send the <literal>SIGINT</literal> signal
!    to the process running that command. To terminate a backend process
!    cleanly, send <literal>SIGTERM</literal> to that process. See
!    also <function>pg_cancel_backend</> and <function>pg_terminate_backend</>
!    in <xref linkend="functions-admin-signal"> for the SQL-callable equivalents
!    of these two actions.
    </para>
  
    <para>
!    The <command>postgres</command> server uses <literal>SIGQUIT</literal>
!    to tell subordinate server processes to terminate without normal
!    cleanup.
!    This signal <emphasis>should not</emphasis> be used by users.  It
     is also unwise to send <literal>SIGKILL</literal> to a server
     process &mdash; the main <command>postgres</command> process will
     interpret this as a crash and will force all the sibling processes

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