Document that Solaris can't use effective_io_concurrency because of an

ineffective posix_fadvise().

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.213 2009/03/26 20:55:49 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.214 2009/04/02 22:44:10 momjian Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -1253,8 +1253,7 @@ SET ENABLE_SEQSCAN TO OFF;
          function, which some operating systems lack.  If the function is not
          present then setting this parameter to anything but zero will result
          in an error.  On some operating systems the function is present but
-         does not actually do anything.  On such systems setting a nonzero
-         value will add CPU overhead without improving performance.
+         does not actually do anything (e.g. Solaris).
         </para>
        </listitem>
       </varlistentry>