Email Engine architecture
Email Engine modules
The Email Engine includes the following modules:
Module | Description |
|---|---|
Monitor | Monitors the mailbox for statistical information such as when the connection dropped and the length of time the connection was down. |
Receiver | Runs in separate threads to maximize speed and reliability.
|
Execution | Parses and executes messages in the message queue. |
Creator | Creates an email based on a template and the data it retrieves from AR System.
|
Sender | Runs as a separate thread, and sends formatted messages to the mail server. |
Logging | Logs messages, error messages, and warnings to the Remedy AR System Email Errors form or local file. |
Configuration | Synchronizes configuration information for the Email Engine using the Centralized Configuration of AR System. Note that BMC also supports the EmailDaemon.properties file. |
All modules run as separate threads. An incoming mailbox uses two threads to process email in the message queue—the Receiver and Execution modules. An outgoing mailbox uses separate threads running for the Creator and Sender modules to format and send outgoing messages.
You can specify various troubleshooting parameters, for example, the queue size of email messages or how finely you want to log information within a module. For more information, see Debugging-options-for-the-Email-Engine and Updating-the-Email-Engine-settings-by-using-the-Centralized-Configuration.
Threading model for outgoing mailboxes
The Sender and Creator threads for every outgoing mailbox depend upon the value set for the NumberOfSenderThreads property and the number of configured outgoing mailboxes, respectively.
Depending upon the NumberOfSenderThreads value and the number of configured outgoing mailboxes, a connection pool is created. The Sender thread uses the connections from this connection pool to send the outgoing messages. The number of connections for each configured outgoing mailbox depends on the number of Sender threads.
The following figure explains this concept in detail.
Threading model for multiple outgoing mailboxes
As shown in the figure, there are three configured outgoing mailboxes, and the value of NumberOfSenderThreads is assumed to be 2. Consequently, two Sender threads and a connection pool with six connections (two connections for every mailbox) is created. The Sender threads send the outgoing messages from the common message queue created for the three Creator threads by using the connections from this connection pool.