Some queries may need the fragments that belong to partition to be
emitted in the reversed order. Current support for that is very limited
(see #1413), but should work reasonably well for small partitions.
Currently flat_mutation_reader_from_mutation_reader()'s
converting_reader will throw std::runtime_error if fast_forward_to() is
called when its internal streamed_mutation_opt is disengaged. This can
create problems if this reader is a sub-reader of a combined reader as the
latter has no way to determine the source of a sub-reader EOS. A reader
can be in EOS either because it reached the end of the current
position_range or because it doesn't have any more data.
To avoid this, instead of throwing we just silently ignore the fact that
the streamed_mutation_opt is disengaged and set _end_of_stream to true
which is still correct.
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <83d309b225950bdbbd931f1c5e7fb91c9929ba1c.1511180262.git.bdenes@scylladb.com>
Rename flat_mutation_reader_from_mutation to
flat_mutation_reader_from_mutations.
Make it work with std::vector<mutation> instead of a single
mutation.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
This is a utility method that will be handy in conversion
from mutation_reader to flat_mutation_reader.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
This commit copies streamed_mutation_from_mutation
from streamed_mutation to flat_mutation_reader
and renames it to streamed_mutation_from_mutation_copy.
This copy will be used as a base for
flat_mutation_reader_from_mutation.
The purpose of this commit is to make it easier to review the next
commit.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
It will add the ability to fast_forward_to on position_range
to flat_mutation_reader that does not have this ability.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
This commit copies make_forwardable from streamed_mutation
to flat_mutation_reader and renames it to make_forwardable_copy.
This copy will be used as a base for make_forwardable implementation
for flat_mutation_reader.
The purpose of this commit is to make it easier to review the next
commit.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
This reader operates on mutation_fragments instead of
streamed_mutations.
Each partition starts with a partition_header fragment
and ends with end_of_partition fragment.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
