Understanding the timestamp of ltrace

[Dmitry Kurochkin]

Hi Frank, Pavel.

Pavel Kazlenka <panya_qwert at tut.by> writes:

> Hi Franck,
>
> Sorry for obvious action, but could you check unix file 
> permissions/owners for log files? If you e.g. scp'ed server logs to 
> client machine there is a chance that user running polygraph-ltrace 
> really have no permission to read *.log file.
>

It does not seem like a permission problem since the same command works
for server side only logs.

> Best wishes,
> Pavel
>
> On 07/17/2013 07:43 PM, Franck Youssef wrote:
>> Hi Pavel,
>>
>>>> Furthermore, when printing the 'time' object using --time_unit 1s, I obtain some kind of a funny timestamp prefixed with a dash: "-2147483620.50"  (= Fri Dec 13 21:46:19 MET 1901 using date -d @…).
>>> This seems like a bug. What polygraph version do you use?
>> I am using the latest public stable release (a.k.a. v. 4.3.2).
>> Using polygraph-lr, the timing is correct. However, they are false with polygraph-ltrace.
>>
>>> You could modify sampling interval using '--win_len' option. Do not use '--time_unit' option if you want unix timestamps.
>>> e.g.
>>> $ polygraph-ltrace --objects time, err_xact.count --win_len 20sec <lo
>> Thanks! This works like a charm!
>>
>> Furthermore, I experience issues when inspecting logs from multiple clients and servers hosts.
>> When running
>> $ polygraph-ltrace --object err_xact.count --side all *.log
>>
>> I obtain the following errors:
>> server1.log:warning: failed to read log file, skipping
>> server2.log:warning: failed to read log file, skipping
>> … for all the servers logs
>> followed by the "normal" ltrace output based on the clients logs only.
>>
>> Whey running the same command on the server logs only, the trace is correct and no warnings are issued. It works also correctly with client logs only.
>> However, when starting to mix client and server logs together, I obtain again warnings on STDERR.
>>
>> The error happens on any --side all|clt|srv and --sync_times 0|1 combination.
>> Also possibly related, when using polygraph-reporter on the same logs, the polygraph-reporter app gets killed after passing to server-side plots. The crash does not happen with client logs only.
>>
>> Is that also a bug, or am I misunderstanding the logging mechanism?
>>

This is definitely a bug, reporter should never crash.  Do all client
and server hosts use the same workload?  Can you please provide a
backtrace for the reporter crash (dump core, run "gdb polygraph-reporter
core" command, run "bt" command)?  Or even better, would it be possible
for you to give us the binary logs (privately)?  That would make it much
easier for us to triage the bug.

Regards,
  Dmitry

>>
>> Thank you a lot for your explanations.
>>
>> Cheers,
>>
>> Franck
>
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