[GitHub] [skywalking-nodejs] tom-pytel edited a comment on pull request #52: Cold start detection and marking

[GitBox <gi...@apache.org>]

tom-pytel edited a comment on pull request #52:
URL: https://github.com/apache/skywalking-nodejs/pull/52#issuecomment-844083225


   > In the code start case, is there any chance to separate the booting process and request handling process? These are typical differences in most cases I am familiar with. Or do you mean, this code starting begins after receiving a request? I don't know this kind of case.
   
   The `coldStart` tag doesn't really give information about the endpoint where it applies in isolation but rather explains the slower than normal execution of an upstream parent span which waits on this child. For one cold started child alone there is no way to determine the length of the bootup since the span starts once the boot is complete and in theory will execute more or less the same as if it was not a cold start (except for any unfilled caches and things like that). If you have both cold and non-cold versions of an endpoint then you can estimate the time of bootup alone by subtracting the normal non-coldStart average from the coldStart average, visually:
   ```
                 0   1   2   3   4
   
   /parent       +-------+
   /child            +---+
   
   /parent       +---------------+
   /child<cold>              +---+
   
   boot time = (/parent - /child<cold>) - (/parent - /child) = 3 - 1 = 2
   ```
   In any case this is just something we do on our side because someone requested it, thought it might be useful info for your side as well.
   
   


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org