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Transaction Safety Overview
The service The Usage Engine service defines a transaction as a unit of data (such as a file) being processed by a stream. A transaction is said to be complete if the file is processed by the stream without errors. Individual transactions are limited to the specified data source. Transactions are separated into two types of categories:
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Transaction safety comes in three types: At-most-once, At-least-once, and Exactly-once.
typically uses transaction Usage Engine typically uses transaction safety of the type Exactly-once, to ensures that the data or file is processed only once during the execution of the stream. However, some functions are designed to include duplicates, and as such acts like transactions safety of the type At-least-once.
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This type is not used in in Usage Engine. |
At-least-once
The result is generated but duplicate results are possible due to multiple deliveries. The following functions use this method:
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Streams using multiple collectors are handled in a way that ensures transaction safety. Each collector is handled in turn, determined by Usage Engine. Each collector adds to a queue, once the collector is ready to read the input.
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