This is slightly awkwards, since the directory structure is not sharded.
This requires some processing to occur outside the shard, while the rest
is sharded.
Returning a reference to the keyspace is dangerous in that the keyspace can
be moved away, when we start futurizing the add_keyspace() process. Make
it return void and look up the keyspace at the point of use.
Reduces coupling. User's should not rely on the fact that it's an
std::map<>. It also allows us to extend row's interface with
domain-specific methods, which are a lot easier to discover than free
functions.
If method doesn't want to share schema ownership it doesn't have to
take it by shared pointer. The benefit is that it's slightly cheaper
and those methods may now be called from places which don't own
schema.
Deleted cells store deletion time not expiry time. This change makes
expiry() valid only for live cells with TTL and adds deletion_time(),
which is inteded to be used with deleted cells.
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.
In preparation for multiple memtables, move column_family::partitions into
its own class, and forward relevant calls from column_family.
A testonly_all_memtables() function was added to support sstable_test.
Currently we use the first byte of the token for determining the local
shard. This is suboptimal for two reasons:
1. the first bytes of the token were already used to select the node,
so they are not randomly distributed
2. using a single byte is not sufficient for large core counts, as the
modulo operation will not return evenly distributed results
Fix by using the final two bytes of the token.
A lookup can cause several data sources to be merged, in which case we will
have to return a temporary (containing data from all the data sources).
For simplicity, we start by always returning a temporary.
Ensure that read-side accessors are const. This is important in preparation
for multiple memtables (and later, sstables) since a read-side
mutation_partition may be a temporary object coming from multiple memtables
(and sstables) while a write-side mutation_partition is guaranteed to belong
to a single memtable (and thus, not be temporary).
Since writers will want non-const mutation_partitions to write to, they won't
be able to use the read-side accessors by accident.
Some tests (eg murmur_hash_test) need only byte manipulation
functions. By specifying dependencies precisely we can drastically
reduce recompilation times, which speeds up development cycle.
I managed to reduce recompilation time for murmur_hash_test from 5
minutes to 4 seconds by breaking dependency on whole urchin object
set.
Use commit log in database, from Calle:
"Initial" usage of the commitlog in database mutation path.
A commitlog is created in "work" dirs when initing the db
from a datadir. However, since we have neither disk data storage,
nor replay capability yet (and no real db config), the settings
are basically to just write in-memory serialization, write them to
disk and then discard them. So in fact, pointless. But at least using
the log...
* A commitlog is created in "work" dirs when initing the db
from a datadir. However, since we have neither disk data storage,
nor replay capability yet (and no real db config), the settings
are basically to just write in-memory serialization, write them to
disk and then discard them. So in fact, pointless. But at least using
the log...
* Moved the actual "apply" of mutation into database. If a commitlog
is active, add an entry to it before applying mutation.
Partitions should be ordered using Origin's ordering, which is first
by token, then by Origin's representation of the key. That is the
natural ordering of decorated_key.
This also changes mutation class to hold decorated_key, to avoid
decoration overhead at different layers.
