For volatile documents and guaranteed documents, the Time to live property of a document type determines how long instances of that document type remain valid after being published. The time to live commences when the Broker receives a document from a publishing client. If the time to live elapses before the client retrieves the document, the Broker discards the document the next time the client requests documents from its queue.

By default, Broker does not actively check if a document has exceeded its time to live. A document's time to live is checked only when a client retrieves the document. An expired document is discarded when the Broker attempts to deliver it to the client. This behavior can be changed for volatile documents only by allowing Broker to proactively delete volatile expired documents based on their combined size. For more information, see Proactively Deleting Documents from a Client Queue.

The time to live can be useful for documents containing data that is updated regularly, such as stock quotes. If a document is generated for a quote every 20 seconds, the time to live can be set to 20. If a client does not retrieve the quote after 20 seconds, then it is discarded because a newer value will arrive soon.

When you set the time to live, you specify the number of seconds before the document expires. If you do not want the document to expire, you can specify a value of 0 (zero). For more information about setting the Time to Live value for a document type, see Modifying Document Type Properties.

Note that changing the time to live for a document type using My webMethods can cause the document type on the Broker to become unsynchronized with the document type on the client application.

For example, suppose you use Designer to create a document type and then make the document type publishable. This creates a corresponding document type on the Broker. Suppose that when you created the document in Designer, you set the time to live to 30 seconds. If you use My webMethods to change the time to live for the document type to 15 seconds, the document type on the Broker is now unsynchronized with the document type on Integration Server (documents created via Designer are stored on Integration Server).

When it receives a document, Broker uses the time to live specified in the document type on the Broker. If a developer built an application that relied on the time to live value specified in the Integration Server document type, changing the document type time to live using My webMethods might unexpectedly (or negatively) impact the application.