[BugFix] fix exp returns incorrect value

[839224346]

Why I'm doing:

exp func returns NULL when input greater than 6

What I'm doing:

Fixes #issue

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
• I have added documentation for my new feature or new function
• This is a backport pr

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 3.3
  • 3.2
  • 3.1
  • 3.0
  • 2.5

[839224346]

One concern is that should exp returns NULL when std::exp calculates infinity for output that's greater than the max value of double type.

[839224346]

Feels like it should return inf rather than null when the output value of std::exp is greater than the max value of double type, just like other math functions.

[Seaven]

Feels like it should return inf rather than null when the output value of std::exp is greater than the max value of double type, just like other math functions.

ignore the approve, should return NULL when overflow the max value, and the change doesn't explain why exp(7) is NULL ? the result of exp(7) is 1096? it's doesn't hit the limit.

[839224346]

@Seaven The reason that exp(7) returns NULL is ExpCheck function actually compares the output of exp(7) with MAX_EXP_PARAMETER and MAX_EXP_PARAMETER equals to std::log(std::numeric_limits<double>::max()). It should be the output of exp(7) comparing with std::numeric_limits<double>::max().
Furthermore, the exp function should be compatible with pow(e, xxx), which returns inf when the output value is larger than the max value of double type.

[Seaven]

@Seaven The reason that exp(7) returns NULL is ExpCheck function actually compares the output of exp(7) with MAX_EXP_PARAMETER and MAX_EXP_PARAMETER equals to std::log(std::numeric_limits<double>::max()). It should be the output of exp(7) comparing with std::numeric_limits<double>::max(). Furthermore, the exp function should be compatible with pow(e, xxx), which returns inf when the output value is larger than the max value of double type.

@Seaven The reason that exp(7) returns NULL is ExpCheck function actually compares the output of exp(7) with MAX_EXP_PARAMETER and MAX_EXP_PARAMETER equals to std::log(std::numeric_limits<double>::max()). It should be the output of exp(7) comparing with std::numeric_limits<double>::max(). Furthermore, the exp function should be compatible with pow(e, xxx), which returns inf when the output value is larger than the max value of double type.

I get it, I think you find a bug about pow, we should to change the result of pow(e, 710) to null~ for some math expression, starrocks has problem when overflow, we want the result is right-value or null or throw exception, not inf/nan, it's different with MySQL

[839224346]

@Seaven The reason that exp(7) returns NULL is ExpCheck function actually compares the output of exp(7) with MAX_EXP_PARAMETER and MAX_EXP_PARAMETER equals to std::log(std::numeric_limits<double>::max()). It should be the output of exp(7) comparing with std::numeric_limits<double>::max(). Furthermore, the exp function should be compatible with pow(e, xxx), which returns inf when the output value is larger than the max value of double type.

@Seaven The reason that exp(7) returns NULL is ExpCheck function actually compares the output of exp(7) with MAX_EXP_PARAMETER and MAX_EXP_PARAMETER equals to std::log(std::numeric_limits<double>::max()). It should be the output of exp(7) comparing with std::numeric_limits<double>::max(). Furthermore, the exp function should be compatible with pow(e, xxx), which returns inf when the output value is larger than the max value of double type.

I get it, I think you find a bug about pow, we should to change the result of pow(e, 710) to null~ for some math expression, starrocks has problem when overflow, we want the result is right-value or null or throw exception, not inf/nan, it's different with MySQL

Understood, will revise the code shortly.

[github-actions]

[FE Incremental Coverage Report]

✅ pass : 0 / 0 (0%)

[github-actions]

[BE Incremental Coverage Report]

✅ pass : 3 / 3 (100.00%)

file detail

	path	covered_line	new_line	coverage	not_covered_line_detail
🔵	be/src/exprs/math_functions.cpp	3	3	100.00%	[]

[839224346]

@Seaven Pls have a look again~

[mergify]

backport branch-3.3

✅ Backports have been created

• #48015 [BugFix] fix exp returns incorrect value (backport #47842) has been created for branch branch-3.3

[mergify]

backport branch-3.2

✅ Backports have been created

• #48016 [BugFix] fix exp returns incorrect value (backport #47842) has been created for branch branch-3.2

[mergify]

backport branch-3.1

✅ Backports have been created

• #48017 [BugFix] fix exp returns incorrect value (backport #47842) has been created for branch branch-3.1 but encountered conflicts

[mergify]

backport branch-3.0

✅ Backports have been created

• #48018 [BugFix] fix exp returns incorrect value (backport #47842) has been created for branch branch-3.0 but encountered conflicts

[mergify]

backport branch-2.5

✅ Backports have been created

• #48019 [BugFix] fix exp returns incorrect value (backport #47842) has been created for branch branch-2.5 but encountered conflicts