Open stempler opened 6 years ago
Add a comment to make clear that auto-merge affects performance negatively.
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The auto-detect feature in the Merge configuration seems to lead to a very bad performance during the transformation. It seems this problem was introduced already in version 3.2.0 with this PR: https://github.com/halestudio/hale/pull/285.
This problem occurs if there is a significant amount of instances that are merged together within a Merge, because the comparisons done for the auto-detect is O(n²). An additional factor is if there are many attributes that are compared.
Example from a median sized data set (~100k instances, up to ~1000 instances merged together):
Right now the workaround is to explicitly configure properties in the Merge configuration and leave the auto-detect feature turned off.