File streaming only releases the file descriptors of a tablet being
streamed in the very streaming end. Which means that if the streaming
tablet has compaction on largest tier finished after streaming
started, there will be always ~2x space amplification for that
single tablet. Since there can be up to 4 tablets being migrated
away, it can add up to a significant amount, since nodes are pushed
to a substantial usage of available space (~90%).
We want to optimize this by dropping reference to a sstable after
it was fully streamed. This way, we reduce the chances of hitting
2x space amplification for a given tablet.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closesscylladb/scylladb#28505
5b550e94a6