Managing the Vertica database parameters

In Vertica we are able to manage and alter the parameters the database listen to.

How to see the values of a parameter.

Use the query bellow passing the name of the parameter. 
(dbadmin@:5433) [dbadmin] * SELECT * FROM CONFIGURATION_PARAMETERS WHERE
PARAMETER_NAME='AdvanceAHMInterval';
-[ RECORD 1 ]-----------------+---------------------------------------------
node_name                     | ALL
parameter_name                | AdvanceAHMInterval
current_value                 | 180
catalog_value                 | 180
database_value                | 180
default_value                 | 180
source                        | DEFAULT
is_mismatch                   | f
groups                        |
change_under_support_guidance | f
change_requires_restart       | f
description                   | Interval between advancing the AHM (seconds)

 Or by using the SHOW CURRENT statement

(dbadmin@:5433) [dbadmin] * SHOW CURRENT AdvanceAHMInterval;
  level  |        name        | setting
---------+--------------------+---------
 DEFAULT | AdvanceAHMInterval | 180
(1 row)

How to alter the value of a parameter

Base Syntax: 
ALTER DATABASE dbname SET parameter_name = parameter_value;
Example of altering the AdvanceAHMInterval to 200 secounds 
(dbadmin@:5433) [dbadmin]  ALTER DATABASE dcg023 SET AdvanceAHMInterval = 200;
ALTER DATABASE

(dbadmin@:5433) [dbadmin]  SHOW DATABASE dcg023 AdvanceAHMInterval;
name | setting
--------------------+---------
AdvanceAHMInterval | 200

Also we have the option to clear the value of a parameter, this will statement will set the parameter value to its default value.

Base Syntax: 
ALTER DATABASE dbname CLEAR parameter_name;
Example : 
(dbadmin@:5433) [dbadmin]  ALTER DATABASE dcg023 clear AdvanceAHMInterval;
ALTER DATABASE

(dbadmin@:5433) [dbadmin]  SHOW CURRENT AdvanceAHMInterval;
level | name | setting
---------+--------------------+---------
DEFAULT | AdvanceAHMInterval | 180
(1 row)

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