Working with DB shard groups

You perform the following tasks to add and manage a DB shard group for Aurora PostgreSQL Limitless Database.

Topics

• Connecting to your Aurora PostgreSQL Limitless Database DB cluster
• Finding the number of routers and shards in a DB shard group
• Describing DB shard groups
• Rebooting a DB shard group
• Changing the capacity of a DB shard group
• Splitting a shard in a DB shard group
• Adding a router to a DB shard group
• Deleting a DB shard group
• Adding a DB shard group to an existing Aurora PostgreSQL Limitless Database DB cluster

Connecting to your Aurora PostgreSQL Limitless Database DB cluster

To work with Aurora PostgreSQL Limitless Database, you connect to the cluster endpoint. The endpoint automatically detects and abstracts the routers. You don't have to specify individual routers for connection.

You can use psql or any other connection utility that works with PostgreSQL:

$ psql -h DB_cluster_endpoint -p port_number -U database_username -d postgres_limitless

The following example uses the endpoint for the DB cluster that you created in CLI.

$ psql -h my-limitless-cluster.cluster-ckifpdyyyxxx.us-east-1.rds.amazonaws.com -p 5432 -U postgres -d postgres_limitless

Note

The default database for the DB shard group in Aurora PostgreSQL Limitless Database is postgres_limitless.

Using the Limitless Connection Plugin

When connecting to Aurora PostgreSQL Limitless Database, clients connect using the cluster endpoint, and are routed to a transaction router by Amazon Route 53. However, Route 53 is limited in its ability to load balance, and can allow uneven workloads on transaction routers. The Limitless Connection Plugin for the AWS JDBC Driver addresses this by performing client-side load balancing with load awareness. For more information on the AWS JDBC Driver, see Connecting to Aurora PostgreSQL with the Amazon Web Services (AWS) JDBC Driver.

Finding the number of routers and shards in a DB shard group

You can use the following query to find the number of routers and shards:

SELECT * FROM rds_aurora.limitless_subclusters;

 subcluster_id | subcluster_type
---------------+-----------------
 1             | router
 2             | router
 3             | shard
 4             | shard
 5             | shard
 6             | shard

Describing DB shard groups

Use the describe-db-shard-groups AWS CLI command to describe your DB shard groups. The following parameter is optional:

• --db-shard-group-identifier – The name of a DB shard group.

The following example describes a specific DB shard group.

aws rds describe-db-shard-groups --db-shard-group-identifier my-db-shard-group

The output resembles the following example.

{
    "DBShardGroups": [
        {
            "DBShardGroupResourceId": "shardgroup-8986d309a93c4da1b1455add17abcdef",
            "DBShardGroupIdentifier": "my-shard-group",
            "DBClusterIdentifier": "my-limitless-cluster",
            "MaxACU": 1000.0,
            "ComputeRedundancy": 0,
            "Status": "available",
            "PubliclyAccessible": false,
            "Endpoint": "my-limitless-cluster.limitless-ccetp2abcdef.us-east-1.rds.amazonaws.com"
        }
    ]
}

Rebooting a DB shard group

Sometimes you have to reboot your DB shard group, for example when the max_connections parameter changes because of a maximum capacity change.

You can use the AWS Management Console or AWS CLI to change the capacity of a DB shard group.

Console

Use the following procedure.

Sign in to the AWS Management Console and open the Amazon RDS console at https://console.aws.amazon.com/rds/.

1. Navigate to the Databases page.

2. Select the DB shard group that you want to reboot.

3. For Actions, choose Reboot.

4. Choose Confirm.

CLI

To reboot a DB shard group, use the reboot-db-shard-group AWS CLI command with the following parameter:

• --db-shard-group-identifier – The name of a DB shard group.

The following example reboots a DB shard group.

aws rds reboot-db-shard-group --db-shard-group-identifier my-db-shard-group