martin-g commented on code in PR #19409:
URL: https://github.com/apache/datafusion/pull/19409#discussion_r2639367828


##########
datafusion/functions/src/math/log.rs:
##########
@@ -118,13 +118,18 @@ fn log_decimal32(value: i32, scale: i8, base: f64) -> 
Result<f64, ArrowError> {
         )));
     }
 
-    let unscaled_value = decimal32_to_i32(value, scale)?;
-    if unscaled_value > 0 {
+    // Match f64::log behaviour
+    if value <= 0 {
+        return Ok(f64::NAN);
+    }
+
+    if scale < 0 {
+        let actual_value = (value as f64) * 10.0_f64.powi(-(scale as i32));
+        Ok(actual_value.log(base))
+    } else {
+        let unscaled_value = decimal32_to_i32(value, scale)?;
         let log_value: u32 = unscaled_value.ilog(base as i32);

Review Comment:
   `decimal32_to_i32()` could return `0` and then `0.ilog()` will fail



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]


---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to