Store Types

File-Based Stores

The EMS server stores persistent messages in file-based stores. You can use the default store files, or create your own file-based stores. You direct the EMS server to write messages to these store files by associating a destination with a store.

File-based stores are enabled by default, and the server automatically defines three default stores, described below. You do not need to do anything in order to use the default stores.

The section Configuring Multiple Stores describes how to change store settings or create custom stores.

mstores

The mstore is designed to recover quickly after a failover. When mstores are in use, the EMS server starts quickly, but may run more slowly until the mstore cache is fully loaded. This is because the EMS server continually monitors the store in the background. The server reads through the mstore incrementally and discards stale data, such as purged and expired messages.

As a result, expired and purged messages are not immediately removed from the mstore, and may remain in the store longer than they would in a file-based or database store—although they are not delivered to the consumer. These messages are discarded during the periodic scans of the store. The scanning behavior is determined by parameter settings in the store configuration, and is further described in Understanding mstore Intervals.

Because of this behavior, querying the server for a total pending message count may return an inaccurate value. However, querying specific destinations returns an accurate count.

The section Configuring Multiple Stores describes the mstore configuration process. Note that an mstore cannot be configured dynamically.

Database Stores

The EMS server can store messages in one or more database instances. Database stores must be configured to use a supported database. See Database Stores for a full description of this feature.