Connection Manager overview v6.0.0
About Connection Manager?
Connection Manager is a new background worker for EDB Postgres Distributed (PGD) 6.0 that simplifies the process of connection to PGD clusters by providing a single point of entry for client applications. It replaces the previous proxy solution with an integrated approach that exposes read-write, read-only, and HTTP status network interfaces in PGD.
Connection Manager is fully integrated into PGD and is designed to work seamlessly with the existing PGD architecture. Every PGD data node has a Connection Manager instance that listens for incoming connections and routes them to the appropriate node in the cluster, specifically the current write leader in the cluster. It also provides a read-only interface for applications that only need to read data from the cluster.
Using Connection Manager
Connection Manager follows the Postgres server's configuration by default. There are three ports, the read-write port, the read-only port, and the HTTP port. The read-write port is used for write operations, while the read-only port is used for read operations. The HTTP port is used for monitoring and management purposes.
The read-write port is, by default, set to the Postgres port + 1000 (usually 6432). The read-only port is set to the Postgres port + 1001 (usually 6433). The HTTP port is set to the Postgres port + 1002 (usually 6434).
To use Connection Manager, you need to configure your client applications to connect to the read-write or read-only port of the Connection Manager instance running on the data node. The Connection Manager will then route the connection to the appropriate node in the cluster.
Note that the Connection Manager is not a replacement for a load balancer. It is designed to work in conjunction with a load balancer to provide a complete solution for managing connections to PGD clusters. The Connection Manager provides a simple and efficient way to manage connections to PGD clusters, while the load balancer provides additional features such as load balancing and failover. See Load Balancing for more information.
Read-Only connections
Connecting a client to the read-only port provided by connection manager restricts that connection to read-only operations in a similar way to using SET TRANSACTION READ ONLY would, except that it's not possible to change it to read-write. The transaction_read_only GUC correctly reports on in these connections.
TLS and Authentication
The Connection Manager performs TLS termination and pre-authentication. The configuration for these is taken directly from Postgres - pg_hba.conf and server key configuration are used transparently. See authentication for more information.