MySQL Bugs: #114410: Code performance issue

Bug #114410	Code performance issue
Submitted:	19 Mar 2024 14:44	Modified:	4 Oct 2024 22:27
Reporter:	jaesung woo	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / J	Severity:	S3 (Non-critical)
Version:	8.3.0	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
https://github.com/mysql/mysql-connector-j/blob/8.3.0/src/main/protocol-impl/java/com/mysq...

isTimestamp function creates Pattern instance which leads to cpu/memory waste while isTime doesnt

How to repeat:
don't need to repeat

Hi Mr. woo,

Thank you for your bug report.

Can you provide us with a snippet of the code that would enable us to repeat the problem ???

Also, please let us know that you have checked that performance drop is not due to Java's garbage collection.

Thanks in advance.

Hi MySQL Verification Team, 

i think it's quite obvious that the code has performance issue because pattern compile occurs all the time when the method is called. 

you can fix this and also leave this as it is. it's your choice 

thank you

```kt
@Test
fun test() {
    val string = "1234"
    val repeatTime = 1_000_000
    // warmup
    measureTimeMillis {
        repeat(1000) {
            MysqlTextValueDecoder.isTimestamp(string)
            MysqlTextValueDecoder.isTime(string)
        }
    }

    val isTimeElapsed = measureTimeMillis {
        repeat(repeatTime) {
            MysqlTextValueDecoder.isTime(string)
        }
    }
    val isTimestampElapsed = measureTimeMillis {
        repeat(repeatTime) {
            MysqlTextValueDecoder.isTimestamp(string)
        }
    }

    println("isTimeElapsed = $isTimeElapsed ms")
    println("isTimestampElapsed = $isTimestampElapsed ms")
}
```

i just did this and the result as follows: 
isTimeElapsed = 102 ms
isTimestampElapsed = 792 ms

Hello Jaesung Woo,

Thank you for the details.
Verified as described.

Regards,
Ashwini Patil

Posted by developer:
 
Added the following entry to the Connector/J 9.1.0 changelog: 

"isTimestamp() no longer creates a Pattern when it is called, which leads to a better code performance."

Posted by developer:
 
Updated the changelog entry to the following: 

"isTimestamp() no longer creates a regular expression Pattern instance when it is called, which leads to better code performance."