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MemoryTarget improvement. #6022
Description
I noticed that the current MemoryTarget implementation has a few caveats:
- Changes to the
MaxLogsCountproperty doesn't trim the list. - If
MaxLogCountis positive (n), an insertion cost is O(n) (because of a call to RemoveAt(0)) - Enumeration of logs block the writers (!)
It appears that I have a resizable circular buffer implementation that can solve those issues. It's just missing some methods from IList (insert, removeAt) but can serve as a drop in replacement of ThreadSafeList.
Activity
welcome commentedon Oct 8, 2025
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snakefoot commentedon Oct 9, 2025
Yes NLog v6 should probably have changed the interface from
IListto something else likeICollection/IReadOnlyListI would prefer something simple, that maybe rely on existing .NET building blocks. If you have something that is just as simple as ThreadSafeList then pull-request are wellcome (Along with many unit-tests if not relying on standard .NET collection).
Orace commentedon Oct 9, 2025
I'm pretty agree with that 🙄
Alas the implementation is not so simple (and not yet complete).
I run some benchmarks, there is roughly 30% of improvement when writing 1_000_000 messages with
MaxCount = 1000:I'm not sure it's worth it.
snakefoot commentedon Oct 9, 2025
@Orace I guess it is possible to replace with a ConcurrentQueue that also supports reverse enumeration. Would it be something that would be useful for you? (Replaces bad performance on trim with bad performance on random indexing).
Orace commentedon Oct 9, 2025
Thanks for your replies.
In my case, at the end of the day, performance isn’t a real issue. I only need to keep the last 50 log lines for crash reports. I just noticed the current implementation could be improved and wanted to share the idea. (Since I worked on the circular buffer with bulk copy a few days ago).
As you said, exposing a mutable list is not necessary and the API should evolve to only allow snapshots (full or partial), but maybe that needs to be a separate issue.
snakefoot commentedon Oct 9, 2025
Created #6023 for your observation:
Also think the memmove from
RemoveAt(0)only hurts when having more than 1000 items in the List.snakefoot commentedon Oct 18, 2025
Closing issue as resolved due to inactivity.
snakefoot commentedon Sep 16, 2026
Created #6283 that allows Logs-enumeration without blocking application logging.