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From "Taras Bobrovytsky (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4787: Optimize APPX MEDIAN() memory usage
Date Tue, 14 Mar 2017 01:57:00 GMT
Taras Bobrovytsky has posted comments on this change.

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


Patch Set 14:

(10 comments)

http://gerrit.cloudera.org:8080/#/c/6025/14/be/src/exprs/aggregate-functions-ir.cc
File be/src/exprs/aggregate-functions-ir.cc:

Line 908: const static int INIT_CAPACITY = 16;
> move those constants into the classes that use them
Done


Line 981: // stored in a dynamically sized array. See the ".h" file for more details.
> briefly describe memory mgmt, in particular the switch to the inlined repre
The description of the reservoir sample algorithm is there. Removed.


Line 1040:   // contains. Frees the memory of the current object. Requires a call Deserialize()
call
> fix grammar
Done


Line 1062:     DCHECK(!sample_array_inline_);
> dcheck this at the top, makes it easier to pick up on it.
Done


Line 1085:   // reservoir sampling algorithm.
> point out all side effects (increase of capacity; when that fails)
Done


Line 1100:     // First, fill up the dst samples if they don't already exist. The samples
are now
> separate logically separate blocks with blank lines
Done


Line 1124:     if (num_samples_ == 0) {
> single line
Done


Line 1138:   void Free(FunctionContext* ctx) {
> call this Delete, because that's what it basically implements (free() only 
Done


Line 1151:   // resize occurs, this needs to be updated.
> i'm assuming this is the size of the array. comment.
Done


Line 1169:   // Increases the size of the samples array to a rounded up to a power of two
> "array to new_capacity, rounded up to a power of two."
Done


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Gerrit-MessageType: comment
Gerrit-Change-Id: I99adaad574d4fb0a3cf38c6cbad8b2a23df12968
Gerrit-PatchSet: 14
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Jim Apple <jbapple-impala@apache.org>
Gerrit-Reviewer: Marcel Kornacker <marcel@cloudera.com>
Gerrit-Reviewer: Matthew Jacobs <mj@cloudera.com>
Gerrit-Reviewer: Mostafa Mokhtar <mmokhtar@cloudera.com>
Gerrit-Reviewer: Taras Bobrovytsky <tbobrovytsky@cloudera.com>
Gerrit-HasComments: Yes

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