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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML
><HEAD
><TITLE
>UNLISTEN</TITLE
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><H1
>UNLISTEN</H1
><DIV
CLASS="REFNAMEDIV"
><H2
>Name</H2
>UNLISTEN &#8212; Stop listening for notification</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><PRE
CLASS="SYNOPSIS"
>UNLISTEN { <TT
CLASS="REPLACEABLE"
><I
>notifyname</I
></TT
> | * }</PRE
><DIV
CLASS="REFSECT2"
><H3
>Inputs</H3
><P
></P
><P
></P
><DL
><DT
><TT
CLASS="REPLACEABLE"
><I
>notifyname</I
></TT
></DT
><DD
><P
>Name of previously registered notify condition.&#13;</P
></DD
><DT
><TT
CLASS="LITERAL"
>*</TT
></DT
><DD
><P
>All current listen registrations for this backend are cleared.&#13;</P
></DD
></DL
></DIV
><DIV
CLASS="REFSECT2"
><H3
>Outputs</H3
><P
>&#13;<P
></P
></P><DL
><DT
><SPAN
CLASS="RETURNVALUE"
>UNLISTEN</SPAN
></DT
><DD
><P
>Acknowledgement that statement has executed.&#13;</P
></DD
></DL
><P></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><H2
>Description</H2
><P
><B
CLASS="COMMAND"
>UNLISTEN</B
>
is used to remove an existing <B
CLASS="COMMAND"
>NOTIFY</B
> registration.
UNLISTEN cancels any existing registration of the current
<SPAN
CLASS="PRODUCTNAME"
>Postgres</SPAN
> session as a listener on the notify
condition <TT
CLASS="REPLACEABLE"
><I
>notifyname</I
></TT
>.
The special condition wildcard "*" cancels all listener registrations
for the current session.&#13;</P
><P
><A
HREF="sql-notify.html"
><I
>NOTIFY</I
></A
>
contains a more extensive
discussion of the use of <B
CLASS="COMMAND"
>LISTEN</B
> and
<B
CLASS="COMMAND"
>NOTIFY</B
>.&#13;</P
><DIV
CLASS="REFSECT2"
><H3
>Notes</H3
><P
><TT
CLASS="REPLACEABLE"
><I
>classname</I
></TT
>
needs not to be a valid class name but can be any string valid
as a name up to 32 characters long.&#13;</P
><P
>The backend does not complain if you UNLISTEN something you were not
listening for.
Each backend will automatically execute <B
CLASS="COMMAND"
>UNLISTEN *</B
> when
exiting.&#13;</P
><P
>A restriction in some previous releases of
 <SPAN
CLASS="PRODUCTNAME"
>Postgres</SPAN
> that a
<TT
CLASS="REPLACEABLE"
><I
>classname</I
></TT
>
which does not correspond to an actual table must be enclosed in double-quotes
is no longer present.&#13;</P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><H2
>Usage</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>postgres=&#62; LISTEN virtual;
LISTEN
postgres=&#62; NOTIFY virtual;
NOTIFY
ASYNC NOTIFY of 'virtual' from backend pid '12317' received</PRE
>

<PRE
CLASS="PROGRAMLISTING"
>postgres=&#62; UNLISTEN virtual;
UNLISTEN
postgres=&#62; NOTIFY virtual;
NOTIFY
-- notice no NOTIFY event is received
postgres=&#62;</PRE
>&#13;</P
></DIV
><DIV
CLASS="REFSECT1"
><H2
>Compatibility</H2
><P
></P
><DIV
CLASS="REFSECT2"
><H3
>SQL92</H3
><P
>   There is no <B
CLASS="COMMAND"
>UNLISTEN</B
> in <SPAN
CLASS="ACRONYM"
>SQL92</SPAN
>.&#13;</P
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