Fix boundRatio incorrect merge

[wangtZJU]

Changelog category (leave one):

• Bug Fix (user-visible misbehavior in an official stable release)

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Fix boundRatio incorrect merge

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

Information about CI checks: https://clickhouse.com/docs/en/development/continuous-integration/

[alexey-milovidov]

Missing tests. Missing comments. Missing a changelog entry.

[wangtZJU]

Hi @alexey-milovidov , the problem is that when other.empty = true, the original code will still use the other.left.x(which may be any arbitrary value) to update self's state.

I can reproduce it in a 2-nodes cluster,

-- this case mimic CI test 00715_bounding_ratio 
--
-- in node 1, run below queries
create table rate_test on cluster my_cluster (timestamp UInt32, event UInt32) engine=Memory;
insert into rate_test values (0,1000),(1,1001),(2,1002),(3,1003),(4,1004),(5,1005),(6,1006),(7,1007),(8,1008);
create table rate_test_dist (timestamp UInt32, event UInt32) engine=Distributed(my_cluster, currentDatabase(), 'rate_test');

select boundingRatio(timestamp, event) from rate_test;  -- output: 1
select boundingRatio(timestamp, event) from rate_test_dist; -- output: 126

but i don't know how to implement this in CI

[UnamedRus]

Probably, even more "interesting" output
https://fiddle.clickhouse.com/f42759d4-6cbd-4a3d-9261-da6fe6e654a7

[alexey-milovidov]

@wangtZJU, Write tests. Write comments. Write changelog entry.

[wangtZJU]

tests and changelog entry are added

[alexey-milovidov]

Thank you!

[robot-ch-test-poll4]

This is an automated comment for commit c4062de with description of existing statuses. It's updated for the latest CI running

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[alexey-milovidov]

It still lacks comments.

[alexey-milovidov]

It should be added as a new test. The old test should remain untouched.

[alexey-milovidov]

@wangtZJU,

tests and changelog entry are added

But we also need comments in the code.
Writing code without comments is a crime.

[wangtZJU]

@alexey-milovidov fixed

[CLAassistant]

All committers have signed the CLA.