[GH-3146] Optimize the binaryToDecimal function #3147
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parquet-pig has been discussed to be removed: https://lists.apache.org/thread/vh1twzdbvm4fr4sl2wt8swqgq92k8369
Is it actually used in your case @qian0817?
cc @Fokko
| @@ -60,12 +60,12 @@ public void testBinaryToDecimal() throws Exception { | |||
| // Test LONG | |||
| testDecimalConversion(Long.MAX_VALUE, 19, 0, "9223372036854775807"); | |||
| testDecimalConversion(Long.MIN_VALUE, 19, 0, "-9223372036854775808"); | |||
| testDecimalConversion(0L, 0, 0, "0.0"); | |||
| testDecimalConversion(0L, 0, 0, "0"); | |||
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Why do these two lines need change?
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For this use case, 0 is the correct value. Using double to construct BigDecimal previously may lead to potential incorrect behavior.
I did not directly use the parquet-pig module; while writing my own parquet converter, I referenced some code from parquet-pig and then discovered the optimization points here. |
Rationale for this change
#3146
If precision is less than 18, the condition unscaledNew <= -pow(10, 18) || unscaledNew >= pow(10, 18) can not be true, so we can remove the judgment logic here. Additionally, using BigDecimal.valueOf(unscaledNew, scale) is preferable over using BigDecimal.valueOf(unscaledNew / pow(10, scale)), as it does not convert the unscaled value to double.
What changes are included in this PR?
Optimize the binaryToDecimal function
Are these changes tested?
pass unit test.
Are there any user-facing changes?
No
Closes #3146