Enable "log_disconnections" Parameter for PostgreSQL Database Instances

01 Sign in to your Alibaba Cloud account.

02 Navigate to Relational Database Services (RDS) console at https://rdsnext.console.aliyun.com/dashboard.

03 In the left navigation panel, under ApsaraDB RDS, choose Instances.

04 Click on the ID (link) of the PostgreSQL database instance that you want to examine, listed in the Instance ID/Name column. Check the Database Engine column to ensure that the selected resource is a PostgreSQL database.

05 In the RDS resource navigation panel, choose Parameters to access the list of the database parameters configured for the selected PostgreSQL instance.

06 Select the Modifiable Parameters tab and use the Search by parameter name box to find the log_disconnections database parameter. Check the Running Value column to determine the current status of the log_disconnections parameter. If Running Value is set to off, the "log_disconnections" database parameter is not enabled for the selected PostgreSQL database instance.

07 Repeat steps no. 4 – 6 for each PostgreSQL instance provisioned by RDS in your Alibaba Cloud account.

01 Run DescribeDBInstances command (OSX/Linux/UNIX) with custom output filters to list the ID and the database engine of each RDS database instance available within your Alibaba Cloud account:

aliyun rds DescribeDBInstances 
  --output cols=DBInstanceId,Engine

02 The command output should return a list with the requested instance identifiers:

DBInstanceId         | Engine
------------         | ------
pgm-abcd1234abcd1234 | PostgreSQL
pgm-1234abcd1234abcd | PostgreSQL

03 Run DescribeParameters command (OSX/Linux/UNIX) with the name of the RDS PostgreSQL database instance that you want to examine as the identifier parameter, to describe the parameters configured for the selected database instance:

aliyun rds DescribeParameters 
  --DBInstanceId pgm-abcd1234abcd1234

04 The command output should return the list with the database parameters available for the instance:

{
	"RunningParameters": {
		"DBInstanceParameter": [
			{
				"ParameterValue": "Europe/London",
				"ParameterName": "timezone",
				"ParameterDescription": "timezone"
			},
			{
				"ParameterValue": "on",
				"ParameterName": "log_connections",
				"ParameterDescription": "Logs each successful connection."
			},

			...
			
			{
				"ParameterValue": "off",
				"ParameterName": "log_disconnections",
				"ParameterDescription": "Logs end of a session, including duration."
			},

			...

			{
				"ParameterValue": "on",
				"ParameterName": "index_adviser.enable_log",
				"ParameterDescription": "Enable index_adviser logging."
			},
			{
				"ParameterValue": "on",
				"ParameterName": "synchronize_seqscans",
				"ParameterDescription": "Enable synchronized sequential scans."
			}
		]
	},
	"EngineVersion": "16.0",
	"RequestId": "1234ABCD-1234-ABCD-1234-ABCD1234ABCD",
	"ConfigParameters": {
		"DBInstanceParameter": []
	},
	"Engine": "PostgreSQL"
}

05 Repeat steps no. 3 and 4 for each database instance created with RDS within your Alibaba Cloud account.

01 Sign in to your Alibaba Cloud account.

02 Navigate to Relational Database Services (RDS) console at https://rdsnext.console.aliyun.com/dashboard.

03 In the left navigation panel, under ApsaraDB RDS, choose Instances.

04 Click on the ID (link) of the PostgreSQL database instance that you want to configure, listed in the Instance ID/Name column. Check the Database Engine column to ensure that the selected resource is a PostgreSQL database.

05 In the RDS resource navigation panel, choose Parameters to access the list of the database parameters configured for the selected PostgreSQL instance.

06 Select the Modifiable Parameters tab and use the Search by parameter name box to find the log_disconnections database parameter.

07 After the log_disconnections parameter is found, click on the Edit button (pencil icon) next to the actual value, in the Running Value column, replace off with on to enable the parameter, then select OK to save the changes.

08 In the Modify Parameters confirmation box, choose Apply Changes to make the parameter modifications take effect. Select OK to confirm the changes.

09 Repeat steps no. 4 – 8 for each PostgreSQL instance provisioned by RDS in your Alibaba Cloud account.

01 Run ModifyParameter command (OSX/Linux/UNIX) with --Parameters set "{'log_disconnections':'on'}" to enable the "log_disconnections" database parameter for the selected PostgreSQL database instances:

aliyun rds ModifyParameter 
  --DBInstanceId pgm-abcd1234abcd1234 
  --Parameters "{'log_disconnections':'on'}"

02 If successful, the output should return the command request ID:

{
	"RequestId": "1234ABCD-1234-ABCD-1234-ABCD1234ABCD"
}

03 Repeat steps no. 1 and 2 for each database instance created with RDS within your Alibaba Cloud account.