This is in order to avoid frequent misses which have a relatively high
cost. A miss means we need to fetch schema definition from another
node and in case of writes do a schema merge.
If the schema is kept alive only by the incoming request, then it
will be forgotten immediately when the request is done, and the next
request using the same schema version will miss again.
Refs #2608.
Message-Id: <1500632447-10104-1-git-send-email-tgrabiec@scylladb.com>
When loading a schema asynchronously, we're leaving a strong
reference to the loaded schema in the entry's shared future. This
patch fixed this by storing a shared_promised, which is reset when the
schema is loaded.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20170220193654.17439-1-duarte@scylladb.com>
We need to track which schema version were synced with on current node
to avoid triggering the sync on every mutation. We need to sync before
mutating to be able to apply the incoming mutation using current
node's schema, possibly applying irreverdible transformations to it to
make it conform.
