What it is for
Fixing the grouping when the automatic computation gets it wrong. It gets it wrong in two directions: merging what is different, or splitting what is the same.
How meulog groups with no rules at all
Three layers, in this order:
- This screen rules, if any match. They beat everything else, because they were written by someone who watched the grouping fail.
- What the source asked for: madExcept
callstack crc, thefingerprintan SDK sent. - The computation: class, normalized message and top of the stack. It gets it right most of the time.
When to write a rule
- It split what is the same: the message carries something that changes every time and that normalization did not catch. Write a rule that collapses that class into a single group.
- It merged what is different: two distinct bugs with the same class and the same line. Write a rule that uses the message to separate them.
What you record
- Class contains and message matches: what the rule looks for.
- The resulting fingerprint: it can be fixed (all of this is one group) or assembled from pieces of what matched.
- Order: the first match decides.
A rule applies going forward
It decides the group on the way in. What is already in the database stays as it was. To apply it to the past, use Regroup under administering an error: it shows how many occurrences would move before touching anything.
The applied column counts how many times the rule actually matched. A rule sitting at zero for weeks is a rule describing a problem that went away.