All language subtitles for [SubtitleTools.com] Listener Control - Learning Oracle 12c [Video]

In this lesson, we want to
discuss Listener Control.

So the listener is the
process that listens

for incoming connections.

If the listener
isn't running, that

will prevent any
incoming connections.

So the listener has to be
running in order for people

to connect to the database
from the outside, at least

remote connections.

And we use the Listener
Control lsnrctl mainline

tool to manage that listener.

And so it gives us an
array of different commands

and functions that we can
use to control the listener.

But the most common will
be starting and stopping

the listener or looking
at the status for it.

So let's first make a
connection to our database.

Let's use the Kara connection.

And even though this
is on the same machine,

Kara is using the
connection information

that she has in her properties--

so the Hostname, Port,
SID, using that information

to actually go out
over the network,

come back in, and
connect to the database.

So right now, Kara
has a connection.

Let's look at the
Listener Control command.

So lsnrctl.

Let's type "help" just to
look at some of the options

that are available to us.

So we have things here like
start, stop, and reload

and status.

So we can use any
of those commands

within the Listener
Control interface

in order to work
with the listener.

So let's do a status.

So it shows the status
of the listener.

So it has the alias for it,
the version, the date that it

was started, the uptime for it.

How long has the
listener been opened,

the listener parameter file--

so that's the listener.ora--

the log file for it.

And then information
about the endpoints

that it's listening on.

And what we really
are looking for here

is this service
orcl has 1 instance.

So it shows us that
the orcl database

is using this listener
for incoming connections.

So that's a summary
of the status command.

So let's do a stop.

Now the listener is stopped.

And to see an example
of the effect of this,

let's attempt to
connect with Scott.

And it gives us,
"The Network Adapter

could not establish
the connection."

And that's because
the listener is down.

But what about the
Kara connection?

Notice that the Kara
connection is unaffected

because she has already made
contact with the listener,

negotiated her
authentication, and been

connected to the database.

So shutting down
the listener only

prevents incoming connections.

It does not disconnect those
that are already connected.

So let's start our
listener back up.

So we get the similar
information about the time

that it started, just now.

Uptime is 0.

Listener parameter file,
all those kind of things.

So it just gives us that
information as we connect up.

So let's exit from here.

We also want to make
the point that you

don't have to actually go into
the Listener Control interface

in order to access the commands.

We can also do them directly
from the Command line.

So we just feed that
command to Listener Control,

lsnrctl status, and it gives
us the status of the listener.

And so we can do an lsnrctl stop
or a listener control start.

Finally, we wanted to make the
point on the Windows operating

system that there's also
a Windows service that

controls the listener as well.

So if we do services.msc,
brings up the Windows services.

And we go down to
the Oracle section.

And we see one called
OracleOraDB12Home1TNSListener.

And so by stopping and
starting that service,

we can control the
listener as well.