Fucun Chu has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/17008 )

Change subject: IMPALA-10463: Implement ds_theta_sketch() and 
ds_theta_estimate() functions
......................................................................


Patch Set 4:

(3 comments)

http://gerrit.cloudera.org:8080/#/c/17008/2//COMMIT_MSG
Commit Message:

http://gerrit.cloudera.org:8080/#/c/17008/2//COMMIT_MSG@28
PS2, Line 28:    data, the difference is around 1%-10%. ds_hll_estimate() is 
faster
> Did you forgot to add this additional section to the commit msg?
Done


http://gerrit.cloudera.org:8080/#/c/17008/3/be/src/exprs/aggregate-functions-ir.cc
File be/src/exprs/aggregate-functions-ir.cc:

http://gerrit.cloudera.org:8080/#/c/17008/3/be/src/exprs/aggregate-functions-ir.cc@1905
PS3, Line 1905:   if (dst->len == sizeof(datasketches::theta_union)) {
> There is one more thing I don't understand here:
1. theta_union.get_result() returns a compact sketch (compact_theta_sketch), 
does not support updating, and is inconsistent with the initial underlying type 
of dst (update_theta_sketch). This is different from the HLL sketch.
2. Based on the previous question, use theta_union as the underlying type of 
dst.
Relevant comments have been added to the code


http://gerrit.cloudera.org:8080/#/c/17008/3/be/src/exprs/aggregate-functions-ir.cc@1908
PS3, Line 1908:   } else if (dst->len == 
sizeof(datasketches::update_theta_sketch)) {
> A DCHECK would be nice in the else branch to verify that dst->len is sizeof
Done



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I14f24c16b815eec75cf90bb92c8b8b0363dcbfbc
Gerrit-Change-Number: 17008
Gerrit-PatchSet: 4
Gerrit-Owner: Fucun Chu <[email protected]>
Gerrit-Reviewer: Fucun Chu <[email protected]>
Gerrit-Reviewer: Gabor Kaszab <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Comment-Date: Tue, 16 Feb 2021 08:07:40 +0000
Gerrit-HasComments: Yes

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