<entry>Execute monitoring functions that may take <literal>ACCESS SHARE</literal> locks on tables,

potentially for a long time.</entry>

</row>

<row>

<entry>pg_signal_backend</entry>

<entry>Send signals to other backends (eg: cancel query, terminate).</entry>

</row>

<row>

<entry>pg_monitor</entry>

<entry>Read/execute various monitoring views and functions.

This role is a member of <literal>pg_read_all_settings</literal>,

<literal>pg_read_all_stats</literal> and

<literal>pg_stat_scan_tables</literal>.</entry>

</row>

<row>

<entry>pg_signal_backend</entry>

<entry>Signal another backend to cancel a query or terminate its session.</entry>

</row>

</tbody>

</tgroup>

</table>

other system information normally restricted to superusers.

</para>

<para>

The <literal>pg_signal_backend</literal> role is intended to allow

administrators to enable trusted, but non-superuser, roles to send signals

to other backends. Currently this role enables sending of signals for

canceling a query on another backend or terminating its session. A user

granted this role cannot however send signals to a backend owned by a

superuser. See <xref linkend="functions-admin-signal">.

</para>

<para>

Care should be taken when granting these roles to ensure they are only used where

needed to perform the desired monitoring.

</para>

<para>

Administrators can grant access to these roles to users using the GRANT

command:

Administrators can grant access to these roles to users using the

<xref linkend="sql-grant">command, for example:

<programlisting>

GRANT pg_signal_backend TO admin_user;