Progress Sonic ESB Configuration and Management Guide

Chapter 5: Using the Database Service JDBC Drivers
Client Load Balancing
Client load balancing helps distribute new connections to multiple servers in your
environment so that no one server is overwhelmed with connection requests. When client
load balancing is enabled, the order in which primary and alternate database servers are
tried is random. For example, suppose that client load balancing is enabled as shown in
Figure 1.
Sonic Database Service
Figure 1. Client Load Balancing Example
In the example in Figure 1, when client load balancing is enabled the Database Service
first attempts to connect to Database Server B (1). The Database Service then attempts a
connection to Database Server C (2), followed by a connection attempt to Database
Server A (3). In contrast, if client load balancing was not enabled in this scenario, each
database server would be tried in sequential order, primary server first, then each alternate
server based on their entry order in the alternate servers list.
To use client load balancing, specify the following properties in the form property=value
in your connection URL:
● LoadBalancing — Set this property to true to enable load balancing.
● AlternateServers — See “Specifying Primary and Alternate Servers” on page 135.
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1
2
Database Server A
(Primary)
Database Server B
(First Alternate)
Database Server C
(Second Alternate)