Add documentation

diff --git a/raddb/mods-available/sql b/raddb/mods-available/sql
index 8f16ab1..a0f7d6a 100644 (file)
--- a/raddb/mods-available/sql
+++ b/raddb/mods-available/sql
@@ -81,6 +81,9 @@ sql {
        #  lifetime
        #  max_queries
 
+       #  The connection pool is new for 3.0, and will be used in many
+       #  modules, for all kinds of connection-related activity.
+       #
        pool {
                # Number of connections to start
                start = 5
@@ -89,9 +92,15 @@ sql {
                min = 4
 
                # Maximum number of connections
+               #
+               # If these connections are all in use and a new one
+               # is requested, the request will NOT get a connection.
                max = 10
 
                # Spare connections to be left idle
+               #
+               # NOTE: Idle connections WILL be closed if "idle_timeout"
+               # is set.
                spare = 3
 
                # Number of uses before the connection is closed
@@ -105,6 +114,16 @@ sql {
                # idle timeout (in seconds).  A connection which is
                # unused for this length of time will be closed.
                idle_timeout = 60
+
+               # NOTE: All configuration settings are enforced.  If a
+               # connection is closed because of "idle_timeout",
+               # "uses", or "lifetime", then the total number of
+               # connections MAY fall below "min".  When that
+               # happens, it will open a new connection.  It will
+               # also log a WARNING message.
+               #
+               # The solution is to either lower the "min" connections,
+               # or increase lifetime/idle_timeout.
        }
 
        # Set to 'yes' to read radius clients from the database ('nas' table)