Update

Each OS got a limitation on how many files that may be opened per process. This was a great issue on previous MC saves, as the limit is normally less than 8096. This means that reading a whole world would have devastating performance as one need to open and close each file accessed to dodge this limitation.

PixelMap added a soft limit of 128 files. This thought too little, so currently there are tests being done on higher values. Sadly this didn’t affect performance positively.

I guess that the only way to increase performance would be to redesign the current reading of files so it caches it. This may end up in more RAM usage as the files are stored, compressed, in a cache, ready to be read anytime.

The current system is trying to read as many files as possible, but this means that the storage may need to read in parallel, saturating the channel and adding unwanted overhead as the storage tries to keep up.

Having one thread dedicating to caching to the other threads may be one solution to this problem, but there may also be dead time in between each reading.