`collection_type_impl::serialize_mutation_form`
became `collection_mutation(_view)_description::serialize`.
Previously callers had to cast their data_type down to collection_type
to use serialize_mutation_form. Now it's done inside `serialize`.
In the future `serialize` will be generalized to handle UDTs.
`collection_type_impl::deserialize_mutation_form`
became a free standing function `deserialize_collection_mutation`
with similiar benefits. Actually, noone needs to call this function
manually because of the next paragraph.
A common pattern consisting of linearizing data inside a `collection_mutation_view`
followed by calling `deserialize_mutation_form` has been abstracted out
as a `with_deserialized` method inside collection_mutation_view.
serialize_mutation_form_only_live was removed,
because it hadn't been used anywhere.
collection_type_impl::mutation became collection_mutation_description.
collection_type_impl::mutation_view became collection_mutation_view_description.
These classes now reside inside collection_mutation.hh.
Additional documentation has been written for these classes.
Related function implementations were moved to collection_mutation.cc.
This makes it easier to generalize these classes to non-frozen UDTs in future commits.
The new names (together with documentation) better describe their purpose.
Currently the handling of partition tombstones is broken in multiple
ways:
* The partition-tombstone is lost when the bucket is calculated for its
timestamp (due to a misplaced `std::exchange()`).
* When the `partition_start` fragment (containing the partition
tombstone) is actually written to the bucket we emit another
`partition_start` fragment before it because the bucket has not seen
that partition before and we fail to notice that we are actually writing
the partition header.
This bug was allowed to fly under the radar because the unit test was
accidentally not creating partition tombstones in the generated data
(due to a mistake). It was discovered while working on unit tests for
another test and fixing the data generation function to actually
generate partition tombstones.
This patch fixes both problems in the handling of partition tombstones
but it doesn't yet fixes the test. That is deferred until the patch
series which uncovered this bug is merged to avoid merge conflicts.
The other series mentioned here is: [PATCH v6 00/15] compaction: allow
collecting purged data
Fixes: #4683
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20190710092427.122623-1-bdenes@scylladb.com>
This writer implements the core logic of time-window based data
segregation. It splits the fragment stream provided by a reader, such
that each atom (cell) in the stream will be written into a consumer
based on the time-window its timestamp belongs to. The end result is
that each consumer will only see fragments, whoose atoms all have
timestamps belonging to the same time-window.
When a mutation fragment has atoms belonging to different time-windows,
it is split into as many fragments as needed so each has only atoms
that belong to the same time-window.
Currently there is a single mutation_writer: `multishard_writer`,
however in the next path we are going to add another one. This is the
right moment to move these into a common namespace (and folder), we
have way too much stuff scattered already in the top-level namespace
(and folder).
Also rename `tests/multishard_writer_test.cc` to
`tests/mutation_writer_test.cc`, this test-suite will be the home of all
the different mutation writer's unit test cases.
