Configuring X-Trace Logging with Retro

In addition to aggregating resource consumption statistics, Retro can explicitly generate an X-Trace report every time a resource is intercepted. As normal, an X-Trace report will only be generated if the request is part of an X-Trace task (eg, that earlier in the request's execution, XTrace.startTask was called). However, because there are many resources consumed during the execution of even just one request, this can generate many X-Trace reports (for example, reading a 4MB file from HDFS produces approximately 600 additional X-Trace reports).

X-Trace logging can be used even if Retro resource aggregation is disabled (eg, if resource-reporting.aggregation.active = false).

Retro uses the following X-Trace logging classes for its resource reports:

• "Disk" -- disk consumption reports. The Operation field of the report will be one of fileopen, fileread, filewrite, fileflush, filesync, fileop.
• "Execution" -- events related to threads, such as starting and stopping processing in a thread, forking, joining, and sleeping. The Operation field of the report will be one of set, unset, branch, join, waited.
• "Network" -- events related to network. The Operation field of the report will be one of netconnect, netread, netwrite, netflush, netclose, loopback-read, loopback-write.
• "Queue" -- events related to instrumented queues. The Operation field of the report will be one of threadpool-enqueue, threadpool-start, threadpool-end.
• "MonitorLock" -- events related to monitor locks. The Operation field of the report will be one of lockacquire and lockrelease. Monitor locks are not instrumented by default with Retro, and must be configured as described in the build options documentation.
• "ReadWriteLock" -- events related to read/write locks. The Operation field of the report will be one of readlockrequest, readlockacquire, readlockrelease, writelockrequest, writelockacquire, writelockrelease.