In the case there are large number of column families, the sender will
send all the column families in parallel. We allow 20% of shard memory
for streaming on the receiver, so each column family will have 1/N, N is
the number of in-flight column families, memory for memtable. Large N
causes a lot of small sstables to be generated.
It is possible there are multiple senders to a single receiver, e.g.,
when a new node joins the cluster, the maximum in-flight column families
is number of peer node. The column families are sent in the order of
cf_id. It is not guaranteed that all peers has the same speed so they
are sending the same cf_id at the same time, though. We still have
chance some of the peers are sending the same cf_id.
Fixes#3065
Message-Id: <46961463c2a5e4f1faff232294dc485ac4f1a04e.1513159678.git.asias@scylladb.com>
(cherry picked from commit a9dab60b6c)
46dae42dcd