We want to start tracking the memory consumption of mutation fragments.
For this we need schema and permit during construction, and on each
modification, so the memory consumption can be recalculated and pass to
the permit.
In this patch we just add the new parameters and go through the insane
churn of updating all call sites. They will be used in the next patch.
We will soon want to update the memory consumption of mutation fragment
after each modification done to it, to do that safely we have to forbid
direct access to the underlying data and instead have callers pass a
lambda doing their modifications.
Uses where this method was just used to move the fragment away are
converted to use `as_clustering_row() &&`.
We will soon want to update the memory consumption of mutation fragment
after each modification done to it, to do that safely we have to forbid
direct access to the underlying data and instead have callers pass a
lambda doing their modifications.
Uses where this method was just used to move the fragment away are
converted to use `as_static_row() &&`.
Seastar recently lost support for the experimental Concepts Technical
Specification (TS) and gained support for C++20 concepts. Re-enable
concepts in Scylla by updating our use of concepts to the C++20
standard.
This change:
- peels off uses of the GCC6_CONCEPT macro
- removes inclusions of <seastar/gcc6-concepts.hh>
- replaces function-style concepts (no longer supported) with
equation-style concepts
- semicolons added and removed as needed
- deprecated std::is_pod replaced by recommended replacement
- updates return type constraints to use concepts instead of
type names (either std::same_as or std::convertible_to, with
std::same_as chosen when possible)
No attempt is made to improve the concepts; this is a specification
update only.
Message-Id: <20200531110254.2555854-1-avi@scylladb.com>
converting_mutation_partition_applier is a heavyweight class that is not
used in the hot path, so it can be safely out-of-lined. This moves
some includes to boost/multiprecision out of header files, where they
can infect a lot of code.
mutation_partition_view.cc's includes were adjusted to recover
missing dependencies.
and replace all dht::global_partitioner().decorate_key
with dht::decorate_key
It is an improvement because dht::decorate_key takes schema
and uses it to obtain partitioner instead of using global
partitioner as it was before.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
mutation_partition_view now supports a compile-time resolved visitor.
This is performant but results in bloat when the performance is not
needed. Furthermore, the template function that applies the object
to the visitor is private and out-of-line, to reduce compile time.
To allow visitation on mutation_partition_view objects, add a virtual
visitor type and a non-template accept function.
Note: mutation_partition_visitor is very similar to the new type,
but different enough to break the template visitor which is used
to implement the new visitor.
The new visitor will be used to implement pretty printing for
canonical_mutation.
`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.
mutation_partition_view needs to create an atomic_cell from
IDL-serialised data. Then that cell is passed to the visitor. However,
because generic mutation_partition_visitor interface was used, the cell
was passed by constant reference which forced the visitor to needlessly
copy it.
This patch takes advantage of the fact that mutation_partition_view is
devirtualised now and adjust the interfaces of its visitors so that the
cell can be passed without copying.
There are only two types of visitors used and only one of them appears
in the hot path. They can be devirtualised without too much effort,
which also enables future custom interface specialisations specific to
mutation_partition_views and its users, not necessairly in the scope of
more general mutation_partition_visitor.
Some users (e.g. reconciliation code) need only to know the clustering
key of the first or the last row in the partition. This was done with a
full visitor visiting every single cell of the partition, which is very
wasteful. This patch adds direct getters for the needed information.
Collections are not going to be fully converted to the IMR just yet and
still use the old serialisation format. This means that they still don't
support fragmented values very well. This patch passes the information
when an atomic_cell is created as a member of a collection so that later
we can avoid fragmenting the value in such cases.
As a prepratation for the switch to the new cell representation this
patch changes the type returned by atomic_cell_view::value() to one that
requires explicit linearisation of the cell value. Even though the value
is still implicitly linearised (and only when managed by the LSA) the
new interface is the same as the target one so that no more changes to
its users will be needed.
This patch introduces IDL definition as well as serialisers and
deserialisers for freezing mutation_fragment so that they can be
transferred between nodes in a cluster.
This will allow expressing lack of information about certain ranges of
rows (including the static row), which will be used in cache to
determine if information in cache is complete or not.
Continuity is represented internally using flags on row entries. The
key range between two consecutive entries is continuous iff
rows_entry::continuous() is true for the later entry. The range
starting after the last entry is assumed to be continuous. The range
corresponding to the key of the entry is continuous iff
rows_entry::dummy() is false.
[tgrabiec:
- based on the following commits:
4a5bf75 - Piotr Jastrzebski : mutation_partition: introduce dummy rows_entry
773070e - Piotr Jastrzebski : mutation_partition: add continuity flag to rows_entry
- documented that partition tombstone is always complete
- require specifying the partition tombstone when creating an incomplete entry
- replaced rows_entry(dummy_tag, ...) constructor with more general
rows_entry(position_in_partition, ...)
- documented continuity semantics on mutation_partition
- fixed _static_row_cached being lost by mutation_partition copy constructors
- fixed conversion to streamed_mutation to ignore dummy entries
- fixed mutation_partition serializer to drop dummy entries
- documented semantics of continuity on mutation_partition level
- dropped assumptions that dummy entries can be only at the last position
- changed equality to ignore continuity completely, rather than
partially (it was not ignoring dummy entries, but ignoring
continuity flag)
- added printout of continuity information in mutation_partition
- fixed handling of empty entries in apply_reversibly() with regards
to continuity; we no longer can remove empty entries before
merging, since that may affect continuity of the right-hand
mutation. Added _erased flag.
- fixed mutation_partition::clustered_row() with dummy==true to not ignore the key
- fixed partition_builder to not ignore continuity
- renamed dummy_tag_t to dummy_tag. _t suffix is reserved.
- standardized all APIs on is_dummy and is_continuous bool_class:es
- replaced add_dummy_entry() with ensure_last_dummy() with safer semantics
- dropped unused remove_dummy_entry()
- simplified and inlined cache_entry::add_dummy_entry()
- fixed mutation_partition(incomplete_tag) constructor to mark all row ranges as discontinuous
]
This patch replaces the current row tombstone representation by a
row_tombstone.
The intent of the patch is thus to reify the idea of shadowable
tombstones, that up until now we considered all materialized view row
tombstones to be.
We need to distinguish shadowable from non-shadowable row tombstones
to support scenarios such as, when inserting to a table with a
materialzied view:
1. insert into base (p, v1, v2) values (3, 1, 3) using timestamp 1
2. delete from base using timestamp 2 where p = 3
3. insert into base (p, v1) values (3, 1) using timestamp 3
These should yield a view row where v2 is definitely null, but with
the current implementation, v2 will pop back with its value v2=3@TS=1,
even though its dead in the base row. This is because the row
tombstone inserted at 2) is a shadowable one.
This patch only addresses the memory representation of such
row_tombstones.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
This patch changes the type of the mutation partition's row_tombstones
to be a range_tombstone_list, so that they are now represented as a
set of disjoint ranges. All of its usages are updated accordingly.
Fixes#1155
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
... and make it a clustering_key_prefix, in preparation of
supporting not-whole-row range tombstones.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Fixes#927.
The new visiting code builds cell instances using
atomic_cell::make_*() factory methods, which won't work in LSA context
because they depend on managed_bytes storage to be linearized. It may
not be since large blob support. This worked before because we created
cells from views before which works in all contexts.
Fix by constructing them in standard allocator context.
Message-Id: <1456234064-13608-2-git-send-email-tgrabiec@scylladb.com>
The line:
boost::apply_visitor(atomic_cell_or_collection_visitor(std::move(visitor), id, col), cell);
is executed in a loop, so visitor could be used after being
moved-from. This may not always be allowed for some visitors. Also,
vistors may keep state, which should be preserved for the whole
visitation.
This doesn't fix any issue right now.
Message-Id: <1456234064-13608-1-git-send-email-tgrabiec@scylladb.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.
