Doc: add explanation when pg node status is shown as "unknown".

diff --git a/doc/src/sgml/ref/pcp_node_info.sgml b/doc/src/sgml/ref/pcp_node_info.sgml
index 18d130c76cde67bc47d56abc94f6c11ff477f608..016669c707e781f1fa4c820d0bddf67ac94bd071 100644 (file)
--- a/doc/src/sgml/ref/pcp_node_info.sgml
+++ b/doc/src/sgml/ref/pcp_node_info.sgml
@@ -118,7 +118,10 @@ $ pcp_node_info -w -p 11001 -n 1
    available in <productname>PostgreSQL</productname> 9.1 or later. If
    <productname>Pgpool-II</productname> was built with
    <productname>PostgreSQL</productname> 9.0 or earlier, the column
-   shows "unknown". When a backend node is detached by <xref
+   shows "unknown". Also
+   if <link linkend="runtime-config-health-check">health check</link>
+   is disabled, it shows "unknown".
+   When a backend node is detached by <xref
    linkend="pcp-detach-node">, the status managed by
    <productname>Pgpool-II</productname> will be "down", while the
    actual backend status is "up". Thus it is possible that 5 does not