This patch avoids moving entries from range tombstones and clustering
rows sets in streamed_mutation_from_mutation(). Such action breaks these
sets as the entries will be left in some unknown state.
Instead, the sets are being broken in a supported and predictable way
using unlink_leftmost_without_rebalance().
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
Message-Id: <1468843205-18852-1-git-send-email-pdziepak@scylladb.com>
Originally, streamed_mutations guaranteed that emitted tombstones are
disjoint. In order to achieve that two separate objects were produced
for each range tombstone: range_tombstone_begin and range_tombstone_end.
Unfortunately, this forced sstable writer to accumulate all clustering
rows between range_tombstone_begin and range_tombstone_end.
However, since there is no need to write disjoint tombstones to sstables
(see #1153 "Write range tombstones to sstables like Cassandra does") it
is also not necessary for streamed_mutations to produce disjoint range
tombstones.
This patch changes that by making streamed_mutation produce
range_tombstone objects directly.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
reverse_streamed_mutation() is an inefficient way of reversing
streamed_mutations. First, it collects all mutation_fragments and then
it emits them in the reversed orders (except static row which always is
the first element and it also flips the bounds of range tombstones).
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
range_tombstone_stream encapsulates logic responsible for turning
range_tombstone_list into a stream of mutation_fragments and merging
that stream with a stream of clustering rows.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
streamed_mutation represents a mutation in a form of a stream of
mutation_fragments. streamed_mutation emits mutation fragments in the
order they should appear in the sstables, i.e. static row is always
the first one, then clustering rows and range tombstones are emitted
according to the lexicographical ordering of their clustering keys and
bounds of the range tombstones.
Range tombstones are disjoint, i.e. after emitting
range_tombstone_begin it is guaranteed that there is going to be a
single range_tombstone_end before another range_tombstone_begin is
emitted.
The ordering of mutation_fragments also guarantees that by the time
the consumer sees a clustering row it has already received all
relevant tombstones.
Partition key and partition tombstone are not streamed and is part of
the streamed_mutation itself.
streamed_mutation uses batching. The mutation implementations are
supposed to fill a buffer with mutation fragments until is_buffer_full()
or the end of stream is encountered.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
This commit introduces mutation_fragment class which represents the parts
of mutation streamed by streamed_mutation.
mutation_fragment can be:
- a static row (only one in the mutation)
- a clustering row
- start of range tombstone
- end of range rombstone
There is an ordering (implemented in position_in_partition class) between
mutation_fragment objects. It reflects the order in which content of
partition appears in the sstables.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
