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Sumo Logic

Understand LogCompare Results

LogCompare results are displayed in the Signatures tab, in the Count and Score columns.

Count

In the Count column, LogCompare results are shown under the count numbers, which appear as blue links. (This is the count from the target query, not the baseline query.) The LogCompare results are the black words and percentages beneath the blue links.

logcompare_count.png

The Count column shows the absolute number of signatures found in the target query.

You will see that some clusters are "new" and some are "gone," especially if you have used a target query that is different from the baseline query. So, if a signature is shown as "gone" (meaning, it was in the baseline query, but is missing in the target query) the count for it will be zero.

You will also see the percentage of changes in your log messages.

These changes are defined as:

  • Delta Percentage. The delta percentage is the straight percentage change in the number of messages divided by the historical count percentage, which is the historical count change over time since the initial count results for this cluster.
  • New. When the word "new" appears, the cluster did not exist in the original baseline.
  • Gone. When the word "gone" appears, a previous cluster did not return in the target query.

The following table illustrates the way the LogCompare results work. For example, the Baseline includes clusters A, B, C, and D. The Target includes A, B, D, and E.

Baseline Delta Results Target
A < + % A
B > - % B
C gone  
D < + % D
  new E

So in this example, C is "gone" in the Target results, and E is "new". Between the matching clusters, LogCompare reports the percentages of changes in the log message for that time shift.

Score

The Score column is calculated based on the significance of the change in the occurrence of that specific pattern, compared to the baseline. So the higher the score, the more significant the change in this message.

The value is calculated using a symmetric version of Kullback-Leibler divergence score.

logcompare_score.png