From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Thu, 10 Sep 2009 15:02:46 +0000 (+0000)
Subject: Add note that the logging collector can block backends in high load situations.
X-Git-Url: http://git.postgresql.org/gitweb/-?a=commitdiff_plain;h=e9d9e2baad75fdf50c85ed55265d2797d24fb48b;p=users%2Fsimon%2Fpostgres.git

Add note that the logging collector can block backends in high load situations.
---

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index a775c52e54..220befa2de 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2422,6 +2422,19 @@ local0.*    /var/log/postgresql
          is dynamic-linker failure messages).
          This parameter can only be set at server start.
        </para>
+
+       <note>
+        <para>
+          The logging collector is designed to never lose messages.  This means
+          that in case of extremely high load, server processes could be
+          blocked due to trying to send additional log messages when the
+          collector has fallen behind.  In contrast, <application>syslog</>
+          prefers to drop messages if it cannot write them, which means it's
+          less reliable in those cases but it will not block the rest of the
+          system.
+        </para>
+       </note>
+
       </listitem>
      </varlistentry>