Chapter 8. Remote Primary and Replica Modes

Table of Contents

1. Primary Mode
2. Replica Mode
3. Primary Distribution

HammerDB allows for multiple instances of the HammerDB program to run in Primary and Replica modes. Running with multiple modes enables the additional instances to be controlled by a single master instance either on the same load testing server or across the network. This functionality can be particularly applicable when testing Virtualized environments and the desire is to test multiple databases running in virtualized guests at the same time. Similarly this functionality is useful for clustered databases with multiple instances such as Oracle Real Application Clusters and wishing to partition a load precisely across servers. HammerDB Remote Modes are entirely operating system independent and therefore an instance of HammerDB running on Windows can be Primary to one or more instances running on Linux and vice versa. Additionally there is no requirement for the workload to be the same and therefore it would be possible to connect multiple instances of HammerDB running on Windows and Linux simultaneously testing SQL Server, Oracle, MySQL and PostrgreSQL workloads in a virtualized environment. In the bottom right hand corner of the interface the status bar shows the mode that HammerDB is running in. By default this will be Local Mode.

Note that communication between Primary and Replica is enabled by the comm module which opens a default channel called ::comm::comm. If an exterior application attempts to connect then an warning such as follows will be shown.

hammerdb>Warning: Connection from received on ::comm::comm with unknown protocol "ddffdfdfd"

Figure 8.1. Mode