The AWS Advanced .NET Data Provider Wrapper is complementary to existing .NET database drivers and aims to extend their functionality to enable applications to take full advantage of the features of clustered databases such as Amazon Aurora. The AWS Advanced .NET Data Provider Wrapper does not connect directly to any database, but enables support of AWS and Aurora functionalities on top of an underlying .NET driver of the user's choice.
Hosting a database cluster in the cloud via Aurora is able to provide users with sets of features and configurations to obtain maximum performance and availability, such as database failover. However, at the moment, most existing drivers do not currently support those functionalities or are not able to entirely take advantage of it.
The main idea behind the AWS Advanced .NET Data Provider Wrapper is to add a software layer on top of an existing .NET driver that would enable all the enhancements brought by Aurora, without requiring users to change their workflow with their databases and existing .NET drivers.
In an Amazon Aurora database cluster, failover is a mechanism by which Aurora automatically repairs the cluster status when a primary DB instance becomes unavailable. It achieves this goal by electing an Aurora Replica to become the new primary DB instance, so that the DB cluster can provide maximum availability to a primary read-write DB instance. The AWS Advanced .NET Data Provider Wrapper is designed to understand the situation and coordinate with the cluster in order to provide minimal downtime and allow connections to be very quickly restored in the event of a DB instance failure.
Although Aurora is able to provide maximum availability through the use of failover, existing client drivers do not currently support this functionality. This is partially due to the time required for the DNS of the new primary DB instance to be fully resolved in order to properly direct the connection. The AWS Advanced .NET Data Provider Wrapper allows customers to continue using their existing community drivers in addition to having the AWS Advanced .NET Wrapper fully exploit failover behavior by maintaining a cache of the Aurora cluster topology and each DB instance's role (Aurora Replica or primary DB instance). This topology is provided via a direct query to the Aurora DB, essentially providing a shortcut to bypass the delays caused by DNS resolution. With this knowledge, the AWS Advanced .NET Wrapper can more closely monitor the Aurora DB cluster status so that a connection to the new primary DB instance can be established as fast as possible.
Since a database failover is usually identified by reaching a network or a connection timeout, the AWS Advanced .NET Data Provider Wrapper introduces an enhanced and customizable manner to faster identify a database outage.
Enhanced Failure Monitoring (EFM) is a feature that periodically checks the connected database instance's health and availability. If a database instance is determined to be unhealthy, the connection is aborted (and potentially routed to another healthy instance in the cluster).
The AWS Advanced .NET Data Provider Wrapper also works with RDS provided databases that are not Aurora.
See CONTRIBUTING for more information.
This project is licensed under the Apache-2.0 License.
Although this repository is released under the Apache-2.0 License, it supports the use of the third party MySql.Data package. The MySql.Data package's licensing includes the GPL-2.0-only License with Universal-FOSS-exception-1.0.
Although this repository is released under the Apache-2.0 License, it supports the use of the third party NHibernate package. The NHibernate package's licensing includes the LGPL-2.1-only License.