Fix wrong result of cast(float as decimal) when overflow happens (#4380)

[ti-chi-bot]

This is an automated cherry-pick of #4380

What problem does this PR solve?

Issue Number: close #3998

Problem Summary:

What is changed and how it works?

When cast float32 to decimal, use Float64 as intermediate type to avoid overflow.

WATCHOUT: there is performance regression and compatibility issue. Explained in the following comments.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Fix wrong result of cast(float as decimal) when overflow happens

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• guo-shaoge
• wshwsh12

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[guo-shaoge]

/run-all-tests

[VelocityLight]

/merge

[ti-chi-bot]

@VelocityLight: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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[ti-chi-bot]

@VelocityLight: /merge in this pull request requires 2 approval(s).

In response to this:

/merge

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[sre-bot]

Coverage for changed files

Filename                            Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
FunctionsTiDBConversion.h               856               432    49.53%          89                26    70.79%        1940               635    67.27%         496               321    35.28%
tests/gtest_tidb_conversion.cpp        4645              1044    77.52%          37                 0   100.00%        1455                 0   100.00%        1468               746    49.18%
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                  5501              1476    73.17%         126                26    79.37%        3395               635    81.30%        1964              1067    45.67%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
16976      9545             43.77%    191292  96883        49.35%

full coverage report (for internal network access only)

[guo-shaoge]

/merge

[ti-chi-bot]

@guo-shaoge: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: d077eb2

[sre-bot]

Coverage for changed files

Filename                            Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
FunctionsTiDBConversion.h               856               432    49.53%          89                26    70.79%        1940               635    67.27%         496               321    35.28%
tests/gtest_tidb_conversion.cpp        4645              1044    77.52%          37                 0   100.00%        1455                 0   100.00%        1468               746    49.18%
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                  5501              1476    73.17%         126                26    79.37%        3395               635    81.30%        1964              1067    45.67%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
16976      9545             43.77%    191292  96871        49.36%

full coverage report (for internal network access only)