If the cache is enabled, readWithRLock always reads the file using a siphon.
The siphon code copies every byte it reads into a bytes.Buffer. When the full file has been read, that bytes.Buffer is used to update the cache.
However, if the underlying file is e.g. a gigabyte in size, the siphon will end up with a bytes.Buffer containing that entire gigabyte. Unless you've set your cache size to over a gigabyte, this gets thrown away as soon as the ReadStream is done.
The main reason we use ReadStream is so we can deal with very large items without having to stick the entire thing in memory at once. Having discovered this, we'll probably disable the cache, but there are cases where people may wish to have a cache enabled without blowing up their memory!
If the cache is enabled,
readWithRLockalways reads the file using asiphon.The siphon code copies every byte it reads into a bytes.Buffer. When the full file has been read, that bytes.Buffer is used to update the cache.
However, if the underlying file is e.g. a gigabyte in size, the siphon will end up with a bytes.Buffer containing that entire gigabyte. Unless you've set your cache size to over a gigabyte, this gets thrown away as soon as the ReadStream is done.
The main reason we use ReadStream is so we can deal with very large items without having to stick the entire thing in memory at once. Having discovered this, we'll probably disable the cache, but there are cases where people may wish to have a cache enabled without blowing up their memory!