Refactor traverseValidationA' (perf). #110
Merged
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We noticed that when working with moderately large collections (10k items or more), that under certain circumstances
traverseValidationA'
can become very slow. It turns out this only generally occurs if all items in the collection areOk _
. The offending expression is this:This creates a new list for every item in the list and then joins it to another one. This PR replaces that by using the
::
(cons) operator to join at the front, and then at the end of the recursive loop callsList.rev
on it.I've compared old and new implementations with FSCheck and they appear to behave the same before / after.
Performance with Benchmark dotnet on a collection of 1000 items (note that performance does not appear to scale linearly - try this with 100,000 Oks and you'll be waiting a while...).
Three tests - all errors, all successes, or 50/50 split randomly distributed throughout the collection.
P.S. Apologies for the removal of extra EOL characters which distract from the PR - VSCode did that!