Taras Bobrovytsky has posted comments on this change.

Change subject: IMPALA-4787: Optimize APPX_MEDIAN() memory usage
......................................................................


Patch Set 13:

(5 comments)

http://gerrit.cloudera.org:8080/#/c/6025/13/be/src/exprs/aggregate-functions-ir.cc
File be/src/exprs/aggregate-functions-ir.cc:

PS13, Line 1075:     capacity_ = num_samples_;
               :     sample_array_inline_ = true;
> as we discussed in person, let's move this to serialize which is when this 
Done


PS13, Line 1091:         int target_capacity = INIT_CAPACITY;
               :         while (target_capacity < necessary_capacity) 
target_capacity *= 2;
> BitUtil::RoundUpToPowerOfTwo
Done


PS13, Line 1093:         if (target_capacity > MAX_CAPACITY) target_capacity = 
MAX_CAPACITY;
               :         bool result = IncreaseCapacity(ctx, target_capacity);
> this is simplified if IncreaseCapacity takes the max and handles the ceilin
Done. IncreaseCapacity() handles the ceiling.


PS13, Line 1163: may
> may be
Done


PS13, Line 1168:   // if it hasn't been allocated yet. Returns false if the 
operation fails.
               :   bool IncreaseCapacity(FunctionContext* ctx, int 
new_capacity) {
> If you change this to take max_capacity (which always should pass the const
I made some changes. I am not sure if it makes sense to pass max_capacity as a 
parameter, but the ceiling is calculated here as you suggested. Let me know if 
my change makes sense to you.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I99adaad574d4fb0a3cf38c6cbad8b2a23df12968
Gerrit-PatchSet: 13
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Taras Bobrovytsky <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Matthew Jacobs <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Taras Bobrovytsky <[email protected]>
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