Spring Cloud Sleuth
+Spring Cloud Sleuth implements a distributed tracing solution for Spring Cloud.
+Terminology
+Spring Cloud Sleuth borrows Dapper’s terminology.
+Span: The basic unit of work. For example, sending an RPC is a new span, as is sending a response to an RPC. Span’s are identified by a unique 64-bit ID for the span and another 64-bit ID for the trace the span is a part of. Spans also have other data, such as descriptions, key-value annotations, the ID of the span that caused them, and process ID’s (normally IP address).
+Spans are started and stopped, and they keep track of their timing information. Once you create a span, you must stop it at some point in the future.
+Trace: A set of spans forming a tree-like structure. For example, if you are running a distributed big-data store, a trace might be formed by a put request.
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