We current pass a region group to the memtable, but after so many recent
changes, that is a bit too low level. This patch changes that so we pass
a memtable list instead.
Doing that also has a couple of advantages. Mainly, during flush we must
get to a memtable to a memtable_list. Currently we do that by going to
the memtable to a column family through the schema, and from there to
the memtable_list.
That, however, involves calling virtual functions in a derived class,
because a single column family could have both streaming and normal
memtables. If we pass a memtable_list to the memtable, we can keep
pointer, and when needed get the memtable_list directly.
Not only that gets rid of the inheritance for aesthetic reasons, but
that inheritance is not even correct anymore. Since the introduction of
the big streaming memtables, we now have a plethora of lists per column
family and this transversal is totally wrong. We haven't noticed before
because we were flushing the memtables based on their individual sizes,
but it has been wrong all along for edge cases in which we would have to
resort to size-based flush. This could be the case, for instance, with
various plan_ids in flight at the same time.
At this point, there is no more reason to keep the derived classes for
the dirty_memory_manager. I'm only keeping them around to reduce
clutter, although they are useful for the specialized constructors and
to communicate to the reader exactly what they are. But those can be
removed in a follow up patch if we want.
The old memtable constructor signature is kept around for the benefit of
two tests in memtable_tests which have their own flush logic. In the
future we could do something like we do for the SSTable tests, and have
a proxy class that is friends with the memtable class. That too, is left
for the future.
Fixes#1870
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <811ec9e8e123dc5fc26eadbda82b0bae906657a9.1479743266.git.glauber@scylladb.com>
Schemas using compact storage can have clustering keys with the trailing
components not set and effectively being a clustering key prefixes
instead of full clustering keys.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Following what happened to others: we can now include memtable.hh
without including database.hh
Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
The immediate motivation for introducing frozen_mutation is inability
to deserialize current "mutation" object, which needs schema reference
at the time it's constructed. It needs schema to initialize its
internal maps with proper key comparators, which depend on schema.
frozen_mutation is an immutable, compact form of a mutation. It
doesn't use complex in-memory strucutres, data is stored in a linear
buffer. In case of frozen_mutation schema needs to be supplied only at
the time mutation partition is visited. Therefore it can be trivially
deserialized without schema.
