Fix cast datetime to decimal wrong result bug (#4152)

[ti-chi-bot]

This is an automated cherry-pick of #4152

Signed-off-by: guo-shaoge [email protected]

What problem does this PR solve?

Issue Number: close #4151

Problem Summary:

1. wrong const multipiler
2. overflow may hanppens

What is changed and how it works?

1. correct const multipiler
2. use Int128 instead of UInt64 if fsp > 0

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 cast datetime to decimal wrong result bug

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• SeaRise
• mengxin9014

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[guo-shaoge]

/run-all-tests

[guo-shaoge]

/run-all-tests

[sre-bot]

lines: 35.9% (42850 out of 119386)
branches: 5.4% (65711 out of 1221612)

[sre-bot]

lines: 35.9% (42852 out of 119386)
branches: 5.4% (65718 out of 1221612)

[guo-shaoge]

/run-all-tests

[sre-bot]

lines: 36.0% (42937 out of 119386)
branches: 5.4% (65799 out of 1221612)

[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.

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[ti-chi-bot]

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

Commit hash: fd398ab

[ti-chi-bot]

@ti-chi-bot: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

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.

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.

[sre-bot]

lines: 35.9% (42849 out of 119390)
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