Clarify checkpoint docs.

diff --git a/check_postgres.pl b/check_postgres.pl
index 1c306f266a939e98375cb0af0def05c55148079e..2552f4d94ff1fa5f61ac4cf835b7ea9241675c96 100755 (executable)
--- a/check_postgres.pl
+++ b/check_postgres.pl
@@ -7151,10 +7151,10 @@ times larger the relation is compared to how large it should be), just pass in C
 =head2 B<checkpoint>
 
 (C<symlink: check_postgres_checkpoint>) Determines how long since the last checkpoint has 
-been run. This must run on the same server as the database that is being checked. This check is 
-meant to run on a "warm standby" server that is actively processing shipped WAL files, and is meant 
-to check that your warm standby is truly 'warm'. The data directory must be set, either by the 
-environment variable C<PGDATA>, or passing 
+been run. This must run on the same server as the database that is being checked (e.g. the -h 
+flag will not work). This check is meant to run on a "warm standby" server that is actively 
+processing shipped WAL files, and is meant to check that your warm standby is truly 'warm'. 
+The data directory must be set, either by the environment variable C<PGDATA>, or passing 
 the C<--datadir> argument. It returns the number of seconds since the last checkpoint 
 was run, as determined by parsing the call to C<pg_controldata>. Because of this, the 
 pg_controldata executable must be available in the current path. Alternatively, you can