Fix cast datetime to decimal wrong result bug

[guo-shaoge]

Signed-off-by: guo-shaoge shaoge1994@163.com

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 the wrong result that occurs when casting `DATETIME` to `DECIMAL` 

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• windtalker

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[guo-shaoge]

/run-all-tests

[sre-bot]

Coverage for changed files

Filename                                                     Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
/build/tics/dbms/src/Functions/FunctionsTiDBConversion.h         794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                            794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
16548      9504             42.57%    182846  96113        47.43%

full coverage report (for internal network access only)

[guo-shaoge]

/run-integration-test

[guo-shaoge]

/run-check-issue-triage-complete
/run-unit-test

[windtalker]

LGTM

[sre-bot]

Coverage for changed files

Filename                                                     Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
/build/tics/dbms/src/Functions/FunctionsTiDBConversion.h         794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                            794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
16548      9504             42.57%    182846  96102        47.44%

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.

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[ti-chi-bot]

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

Commit hash: 1fdf3bb

[sre-bot]

Coverage for changed files

Filename                                                     Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
/build/tics/dbms/src/Functions/FunctionsTiDBConversion.h         794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                            794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
16715      9483             43.27%    186682  95640        48.77%

full coverage report (for internal network access only)

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #4155.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #4156.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #4157.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #4158.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #4159.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #4160.

[sre-bot]

Coverage for changed files

Filename                                                                                                    Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
/home/jenkins/agent/workspace/tiflash-build-common/tiflash/dbms/src/Functions/FunctionsTiDBConversion.h         794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                                                                                           794               424    46.60%          76                25    67.11%        1786               602    66.29%         474               317    33.12%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
16715      9483             43.27%    186682  95654        48.76%

full coverage report (for internal network access only)