eG Monitoring
 

Measures reported by EcpDataServerTest

One of the most powerful and unique features of Caché is the ability to efficiently distribute data and application logic among a number of server systems. The underlying technology behind this feature is the Enterprise Cache Protocol (ECP): a distributed data caching architecture that manages the distribution of data and locks among a heterogeneous network of server systems. Unlike other "multi-tier" architectures, ECP is primarily a configuration option. That is, you do not have to use special code or development techniques to create distributed database applications. Furthermore, the architecture and operation of ECP is conceptually simple. ECP provides a way to efficiently share data, locks, and executable code among multiple Caché systems. Data and code are stored remotely, but are cached locally to provide efficient access with minimal network traffic. An ECP configuration consists of a number Caché systems that are visible to one another across a TCP/IP-based network. There are two roles a Caché system can play in an ECP configuration:

  • ECP Data Server - a Caché system that is providing data for one or more ECP application server systems.
  • ECP Application Server - a Caché system that is consuming data provided by one or more ECP data server systems.

A Caché system can simultaneously act as both an ECP data server and an ECP application server. However, one Caché instance cannot act as an ECP data server for the data it receives as an application server of another ECP data server.

In an ECP configuration, each ECP data server is responsible for the following:
  • Storing data in its local database
  • Maintaining the coherency of the various ECP application server system database caches so that application servers do not see stale data
  • Managing the distribution of locks across the network

The EcpDataServerTest monitors how well the data server manages data.

Measurement Description Measurement Unit Interpretation
Global_references The number of global references that were served by the data stored in the ECP data server Number Ideally, this value should be low. A high value of this measure could indicate that the ECP application server cache was ineffective in servicing many requests, and has hence redirected them to data server, thereby consuming a lot of network bandwidth.
Requests_received The number of requests received by the data server since the last measurement period Number  
Blocks_sent The number of blocks of data sent by the data server Number  
Data_sent The data sent by the data server since the last measurement period KB  
Data_received The data received by the data server since the last measurement period KB