LCS reshape is basically 'major compacting' level 0 until it contains less than
N sstables.
That produces terrible write amplification, because any given byte will be
compacted (initial # of sstables / max_threshold (32)) times. So if L0 initially
contained 256 ssts, there would be a WA of about 8.
This terrible write amplification can be reduced by performing STCS instead on
L0, which will leave L0 in a good shape without hurting WA as it happens
now.
Fixes#8345.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210322150655.27011-1-raphaelsc@scylladb.com>
bcbb39999b