Known Issues

• Under heavy load the writing of spans might throw an exception due to a mismatch in the counting of the finished spans #2076. Fix slated for v0.68.0

Improvements

• Support 'dd.trace.agent.url' system property and 'DD_TRACE_AGENT_URL' environment variable #1929
• Add peer.hostname to database spans #1943

Changes

• Rework many concurrency instrumentations
  • Instrument RunnableFuture and RejectedExecutionHandler #1973
  • specialised Java FJT/FJP instrumentation and context propagation tests #1961
  • specialised instrumentation for scala promises #1957
  • Scala Promise and Java CompletableFuture instrumentation #1933
  • fix akka/scala FJP internal push context propagation #1948
• Remove WeakReference tracking from PendingTrace #1952
• Silently disable deadlock detection for Java 7 #1947
• Enable OldObjectSample JFR event #1931
• [PROF-1988] default stackdepth #1928
• Add delay before Pending Trace submits to Writer #1916
• Enable embedded mode for JMXFetch #1886

Fixes

• Prevent trace flush from preventing shutdown #1967
• Servlet RequestDispatcher and Spring MVC 404 fixes #1965
• Don't treat dispatch servlet spans as top level #1941
• Delay starting JMXFetch when there's a custom JMX builder #1958