Source services read data in events. An event consists of one or more complete records. Specify the event size for a source service when you configure the source service. Event size defines the maximum length of data that a source service can read or receive at a time, and it determines the performance of a source service. The greater the event size, the more the messages that a source service can include in an event. The default event size is 8192 bytes. The length of the message includes the delimiter.
If a read operation that a source service performs returns an event that is equal to or less than the specified event size, the source publishes the event only if the records in the event contain a delimiter.
Source services optionally use an internal store to store events before sending them to the target services. This store is located on the machine on which the EDS Node that is associated with the source service is running. If there are network connectivity issues or the target services that the source service publish data to go down, the source services store the events in the internal store. When the network connectivity is restored or the target services come up, the source services retrieve data from the store and publish them again.
When you add a source service to data flow, you can configure the internal store options.
If you select the
messaging mode, the internal store of the source service is not supported.
EDS includes the following built-in source services: