Remove useless template instantiations

[solotzg]

What problem does this PR solve?

Issue Number: ref #4909

Problem Summary:

What is changed and how it works?

FunctionsTiDBConversion.h is included in

dbms/src/Common/tests/gtest_mytime.cpp:
dbms/src/Flash/Coprocessor/DAGExpressionAnalyzer.cpp:
dbms/src/Flash/Coprocessor/DAGExpressionAnalyzerHelper.cpp:
dbms/src/Functions/FunctionsTiDBConversion.cpp:
dbms/src/Functions/tests/gtest_tidb_conversion.cpp:

But they all will compile class ExecutableFunctionTiDBCast and class FunctionTiDBCast. We need to reduce useless template instantiation.

Before

**** Files that took longest to parse (compiler frontend):
185258 ms: /data2/work/build-llvm-tiflash/dbms/src/Flash/CMakeFiles/flash_service.dir/Coprocessor/DAGExpressionAnalyzerHelper.cpp.o
182847 ms: /data2/work/build-llvm-tiflash/dbms/src/Functions/CMakeFiles/clickhouse_functions.dir/FunctionsTiDBConversion.cpp.o
181468 ms: /data2/work/build-llvm-tiflash/dbms/src/Flash/CMakeFiles/flash_service.dir/Coprocessor/DAGExpressionAnalyzer.cpp.o

**** Templates that took longest to instantiate:
247991 ms: DB::FunctionTiDBCast::createWrapper<false> (3 times, avg 82663 ms)
240476 ms: DB::FunctionTiDBCast::createWrapper<true> (3 times, avg 80158 ms)

**** Template sets that took longest to instantiate:
488467 ms: DB::FunctionTiDBCast::createWrapper<$> (6 times, avg 81411 ms)
419445 ms: DB::FunctionTiDBCast::createWrapperForDecimal<$> (480 times, avg 873 ms)

After

188112 ms: /data2/work/build-llvm-tiflash/dbms/src/Functions/CMakeFiles/clickhouse_functions.dir/FunctionsTiDBConversion.cpp.o
 20012 ms: /data2/work/build-llvm-tiflash/dbms/src/Flash/CMakeFiles/flash_service.dir/Coprocessor/DAGExpressionAnalyzerHelper.cpp.o
 19898 ms: /data2/work/build-llvm-tiflash/dbms/src/Flash/CMakeFiles/flash_service.dir/Coprocessor/DAGExpressionAnalyzer.cpp.o

**** Files that took longest to parse (compiler frontend):
 85109 ms: DB::FunctionTiDBCast<>::createWrapper<false> (1 times, avg 85109 ms)
 84390 ms: DB::FunctionTiDBCast<>::createWrapper<true> (1 times, avg 84390 ms)
...
 144093 ms: DB::FunctionTiDBCast<$>::createWrapperForDecimal<$> (160 times, avg 900 ms)

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

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• guo-shaoge
• windtalker

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[solotzg]

/run-unit-test

[sre-bot]

Coverage for changed files

Filename                            Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
FunctionsTiDBConversion.cpp              19                14    26.32%           3                 1    66.67%          32                22    31.25%          12                10    16.67%
FunctionsTiDBConversion.h               852               432    49.30%          88                26    70.45%        1933               635    67.15%         494               321    35.02%
tests/gtest_tidb_conversion.cpp        4645              1044    77.52%          37                 0   100.00%        1455                 0   100.00%        1468               746    49.18%
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                  5516              1490    72.99%         128                27    78.91%        3420               657    80.79%        1974              1077    45.44%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
18222      9784             46.31%    204122  97948        52.01%

full coverage report (for internal network access only)

[solotzg]

/run-integration-test

[windtalker]

LGTM

[solotzg]

/merge

[ti-chi-bot]

@solotzg: 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: 5115968

[solotzg]

/hold

[solotzg]

/unhold

[sre-bot]

Coverage for changed files

Filename                            Regions    Missed Regions     Cover   Functions  Missed Functions  Executed       Lines      Missed Lines     Cover    Branches   Missed Branches     Cover
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
FunctionsTiDBConversion.cpp              19                14    26.32%           3                 1    66.67%          32                22    31.25%          12                10    16.67%
FunctionsTiDBConversion.h               852               432    49.30%          88                26    70.45%        1933               635    67.15%         494               321    35.02%
tests/gtest_tidb_conversion.cpp        4645              1044    77.52%          37                 0   100.00%        1455                 0   100.00%        1468               746    49.18%
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL                                  5516              1490    72.99%         128                27    78.91%        3420               657    80.79%        1974              1077    45.44%

Coverage summary

Functions  MissedFunctions  Executed  Lines   MissedLines  Cover
18220      9784             46.30%    203962  97962        51.97%

full coverage report (for internal network access only)