Add support for TCP keepalives on Windows, both for backend and the new

libpq support.

2 files changed, 48 insertions, 30 deletions

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index e54b09545d0..2fbe6a8c24b 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.293 2010/07/06 22:55:26 rhaas Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.294 2010/07/08 10:20:13 mha Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -523,12 +523,17 @@ SET ENABLE_SEQSCAN TO OFF;
       </indexterm>
       <listitem>
        <para>
-        On systems that support the <symbol>TCP_KEEPIDLE</symbol> or
-        <symbol>TCP_KEEPALIVE</> socket option, specifies the
-        number of seconds between sending keepalives on an otherwise idle
-        connection. A value of zero uses the system default. If neither of
-        these socket options is supported, this parameter must be zero. This
-        parameter is ignored for connections made via a Unix-domain socket.
+        Specifies the number of seconds before sending a keepalive packet on an otherwise idle
+        connection.  A value of 0 uses the system default.  This parameter is supported
+        only on systems that support the <symbol>TCP_KEEPIDLE</> or <symbol>TCP_KEEPALIVE</>
+        symbols, and on Windows; on other systems, it must be zero. This parameter is
+        ignored for connections made via a Unix-domain socket.
+         <note>
+          <para>
+           On Windows, a value of 0 will set this parameter to 2 hours,
+           since Windows does not provide a way to read the default value.
+          </para>
+         </note>
        </para>
       </listitem>
      </varlistentry>
@@ -540,11 +545,17 @@ SET ENABLE_SEQSCAN TO OFF;
       </indexterm>
       <listitem>
        <para>
-        On systems that support the <symbol>TCP_KEEPINTVL</symbol> socket option, specifies how
-        long, in seconds, to wait for a response to a keepalive before
-        retransmitting. A value of zero uses the system default. If <symbol>TCP_KEEPINTVL</symbol>
-        is not supported, this parameter must be zero. This parameter is ignored
-        for connections made via a Unix-domain socket.
+        Specifies the number of seconds between sending keepalives on an otherwise idle
+        connection.  A value of 0 uses the system default.  This parameter is supported
+        only on systems that support the <symbol>TCP_KEEPINTVL</>
+        symbol, and on Windows; on other systems, it must be zero. This parameter is
+        ignored for connections made via a Unix-domain socket.
+         <note>
+          <para>
+           On Windows, a value of 0 will set this parameter to 1 second,
+           since Windows does not provide a way to read the default value.
+          </para>
+         </note>
        </para>
       </listitem>
      </varlistentry>
@@ -556,11 +567,16 @@ SET ENABLE_SEQSCAN TO OFF;
       </indexterm>
       <listitem>
        <para>
-        On systems that support the <symbol>TCP_KEEPCNT</symbol> socket option, specifies how
-        many keepalives can be lost before the connection is considered dead.
-        A value of zero uses the system default. If <symbol>TCP_KEEPCNT</symbol> is not
-        supported, this parameter must be zero. This parameter is ignored
-        for connections made via a Unix-domain socket.
+        Specifies the number of keepalive packets to send on an otherwise idle
+        connection.  A value of 0 uses the system default.  This parameter is supported
+        only on systems that support the <symbol>TCP_KEEPCNT</>
+        symbol; on other systems, it must be zero. This parameter is
+        ignored for connections made via a Unix-domain socket.
+         <note>
+          <para>
+           This parameter is not supported on Windows, and must be zero.
+          </para>
+         </note>
        </para>
       </listitem>
      </varlistentry>
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index f70541bb7f1..9e047b110d7 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.312 2010/07/06 21:14:25 rhaas Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.313 2010/07/08 10:20:14 mha Exp $ -->
 
 <chapter id="libpq">
  <title><application>libpq</application> - C Library</title>
@@ -298,10 +298,11 @@
           <para>
            Controls the number of seconds of inactivity after which TCP should
            send a keepalive message to the server.  A value of zero uses the
-           system default.  This parameter is ignored if the neither the
-           <symbol>TCP_KEEPIDLE</> nor the <symbol>TCP_KEEPALIVE</> socket
-           options are supported, for connections made via a Unix-domain
-           socket, or if keepalives are disabled.
+           system default. This parameter is ignored for connections made via a
+           Unix-domain socket, or if keepalives are disabled. It is only supported
+           on systems where the <symbol>TCP_KEEPIDLE</> or <symbol>TCP_KEEPALIVE</>
+           socket option is available, and on Windows; on other systems, it has no
+           effect.
           </para>
          </listitem>
         </varlistentry>
@@ -312,10 +313,11 @@
           <para>
            Controls the number of seconds after which a TCP keepalive message
            that is not acknowledged by the server should be retransmitted.  A
-           value of zero uses the system default.  This parameter is ignored if
-           the <symbol>TCP_KEEPINTVL</> socket option is not supported, for
-           connections made via a Unix-domain socket, or if keepalives are
-           disabled.
+           value of zero uses the system default. This parameter is ignored for
+           connections made via a Unix-domain socket, or if keepalives are disabled.
+           It is only supported on systems where the <symbol>TCP_KEEPINTVL</>
+           socket option is available, and on Windows; on other systems, it has no
+           effect.
           </para>
          </listitem>
         </varlistentry>
@@ -326,10 +328,10 @@
           <para>
            Controls the number of TCP keepalives that can be lost before the
            client's connection to the server is considered dead.  A value of
-           zero uses the system default.  This parameter is ignored if the
-           <symbol>TCP_KEEPCNT</> socket option is not supported, for
-           connections made via a Unix-domain socket, or if keepalives are
-           disabled.
+           zero uses the system default. This parameter is ignored for
+           connections made via a Unix-domain socket, or if keepalives are disabled.
+           It is only supported on systems where the <symbol>TCP_KEEPINTVL</>
+           socket option is available; on other systems, it has no effect.
           </para>
          </listitem>
         </varlistentry>