---------- Forwarded message ---------
From: Abhinav Singh <singhabhinav0796@gmail.com>
Date: Tue, Jun 2, 2020 at 2:20 PM
Subject: Re: RGW JaegerTracing Doubt
To: Yuval Lifshitz <ylifshit@redhat.com>

Here is two commits which for tracing object deletion with function overloading
I can change the code to rgw_op.cc and rgw_rest.cc because they have access to req_state but the functions of RGWRados needs to be rewritten as a whole if we apply overloading, that will be very messy I guess

On Tue, 2 Jun 2020, 14:13 Abhinav Singh, <singhabhinav0796@gmail.com> wrote:
I will share my commit once I build it successfully it will take some time though.

On Tue, 2 Jun 2020, 14:08 Yuval Lifshitz, <ylifshit@redhat.com> wrote:
i think that adding anything "global" to hold info that belongs in a specific call stack is not a good idea.
even if your map is thread_local and would not require any locks (and assuming all processing is done in one thread), its not clear how you can lookup the right requests from different inner function calls?

seems like function overloading is the correct solution.

On Tue, Jun 2, 2020 at 11:22 AM Abhinav Singh <singhabhinav0796@gmail.com> wrote:
Yes you are right, I realized the same thing just moments before.

Could you suggest any tips how to manage this without function overloading?

On Tue, 2 Jun 2020, 13:24 Yuval Lifshitz, <ylifshit@redhat.com> wrote:
the problem with this solution is not the cost of searching the hash map, it is making this map thread safe.
adding a lock would have a very bad impact on performance.

On Tue, Jun 2, 2020 at 5:53 AM Abhinav Singh <singhabhinav0796@gmail.com> wrote:
One way of doing this is to store vector of req_state in and unorderd_map<id,req _state>
But searching through might cause some time latency, so to counter this
I will put a size limit of thousand so that when vector gets big it erases all its element along with unordered_map.
this will ensure that cost of searching operation will be greatly reduced.

Will this do?

On Mon, 1 Jun 2020, 21:34 Abhinav Singh, <singhabhinav0796@gmail.com> wrote:
Hello everyone,

My `req_state*` is containing spans for a particular request to trace that request, but as we know req_state is not available everywhere I tried to insert a req_state variable in CephContext class because every portion of RGW has access to it  and so they will also have access to req_state, but this wont work because it is on time initialized and when request run in parallel race condition might occur and traces will be inaccurate.
The Second method I tried was to include req_state in RGWRadosStore and RGWUserCtl because these are accessible to every function which I want to trace, but again these also have race condition risk.

Can anyone give me any tip how to make req_state available in all functions(if not all then majority) particularly this functions like RGWRadosStore and RGWUserCtl

Thank You.
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