Henry Robinson has posted comments on this change.

Change subject: IMPALA-4187: Switch RPC latency metrics to histograms
......................................................................


Patch Set 2:

(8 comments)

Perf results are in the commit msg now.

http://gerrit.cloudera.org:8080/#/c/4516/2/be/src/rpc/rpc-trace.cc
File be/src/rpc/rpc-trace.cc:

PS2, Line 179: int32_t
> uint32_t?
We typically don't use uint (not consistent in that, unfortunately).


PS2, Line 181: 3
> nit: I've previously learned that it's a good practice not to use "magic" c
Happy to add a comment.


PS2, Line 181: SIXTY_MINUTES_IN_MS
> If I understand correctly, this means the longest RPC call could be 60min. 
Sure, but what's the drawback of having 60 minutes be the upper bound?


http://gerrit.cloudera.org:8080/#/c/4516/2/be/src/util/histogram-metric.h
File be/src/util/histogram-metric.h:

PS2, Line 37: highest_trackable_value, num_significant_digits
> would it be worth to store those in HistogramMetric?
What would be the benefit? They're already stored in HdrHistogram.


Line 44: 
> There's no shared state access before this line. Worth locking from here?
Done


Line 58: 
> And releasing the lock here?
Done


PS2, Line 70: histogram_->Increment(val);
> On an unrelated note, I looked through the implementation of HdrHistogram a
I'm not sure I follow - HdrHistogram is thread-safe (at least per the class 
comment). The reason we have locks here is to protect access to the pointer to 
the histogram object.


PS2, Line 107: boost::scoped_ptr<HdrHistogram> histogram_;
> I know we had a scoped_ptr vs unique_ptr discussion thread recently, but it
Yes, I think that was the result of the conversation so far. scoped_ptr for 
objects whose ownership will never change.


-- 
To view, visit http://gerrit.cloudera.org:8080/4516
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-MessageType: comment
Gerrit-Change-Id: I9ba6d4270dd5676eeeff35ad8d9dc5dcddd95e34
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Henry Robinson <he...@cloudera.com>
Gerrit-Reviewer: Henry Robinson <he...@cloudera.com>
Gerrit-Reviewer: Juan Yu <j...@cloudera.com>
Gerrit-Reviewer: Sailesh Mukil <sail...@cloudera.com>
Gerrit-HasComments: Yes

Reply via email to