The Aurora Initial Connection Strategy Plugin allows users to configure their initial connection strategy, and it can also be used to obtain a connection more reliably if DNS is updating by replacing an out-of-date endpoint.
The following sequence diagram describes the default plugin behaviour if no custom initial connection strategy is provided:
When this plugin is enabled, if the initial connection is to a reader cluster endpoint, the connected reader host will be chosen based on selection strategy specified using the reader_initial_connection_host_selector_strategy parameter.
See initial connection strategy for all possible strategies.
This plugin also helps retrieve connections more reliably. When a user connects to a cluster endpoint, the actual instance for a new connection is resolved by DNS. During failover, the cluster elects another instance to be the writer. While DNS is updating, which can take up to 40-60 seconds, if a user tries to connect to the cluster endpoint, they may be connecting to an old host. This plugin helps by replacing the out of date endpoint if DNS is updating.
To enable the Aurora Initial Connection Strategy Plugin, add initial_connection to the plugins value.
The following properties can be used to configure the Aurora Initial Connection Strategy Plugin.
| Parameter | Value | Required | Description | Example | Default Value |
|---|---|---|---|---|---|
reader_initial_connection_host_selector_strategy |
String | No | The strategy that will be used to select a new reader host when opening a new connection. For more information on the available reader selection strategies, see this table. |
leastConnections |
random |
open_connection_retry_timeout_ms |
Integer | No | The maximum allowed time for retries when opening a connection in milliseconds. | 40000 |
30000 |
open_connection_retry_interval_ms |
Integer | No | The time between retries when opening a connection in milliseconds. | 2000 |
1000 |