Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
Currently all the code operates on the range_tombstone class.
and many of those places get the range tombstone in question
from the range_tombstone_list. Next patches will make that list
carry (and return) some new object called range_tombstone_entry,
so all the code that expects to see the former one there will
need to patched to get the range_tombstone from the _entry one.
This patch prepares the ground for that by introdusing the
range_tombstone& tombstone() { return *this; }
getter on the range_tombstone itself and patching all future
users of the _entry to call .tombstone() right now.
Next patch will remove those getters together with adding the new
range_tombstone_entry object thus automatically converting all
the patched places into using the entry in a proper way.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Some .cc files over the code include the storage service
for no real need. Drop the header and include (in some)
what's really needed.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Commit aab6b0ee27 introduced the
controversial new IMR format, which relied on a very template-heavy
infrastructure to generate serialization and deserialization code via
template meta-programming. The promise was that this new format, beyond
solving the problems the previous open-coded representation had (working
on linearized buffers), will speed up migrating other components to this
IMR format, as the IMR infrastructure reduces code bloat, makes the code
more readable via declarative type descriptions as well as safer.
However, the results were almost the opposite. The template
meta-programming used by the IMR infrastructure proved very hard to
understand. Developers don't want to read or modify it. Maintainers
don't want to see it being used anywhere else. In short, nobody wants to
touch it.
This commit does a conceptual revert of
aab6b0ee27. A verbatim revert is not
possible because related code evolved a lot since the merge. Also, going
back to the previous code would mean we regress as we'd revert the move
to fragmented buffers. So this revert is only conceptual, it changes the
underlying infrastructure back to the previous open-coded one, but keeps
the fragmented buffers, as well as the interface of the related
components (to the extent possible).
Fixes: #5578
Correct counter order is supported for over 2 years and upgrades are only
allowed from versions which already have the support, so the checks
are hereby dropped.
There are some places that get global storage_service instance
for individual features. In the next patch all these helpers
will be removed, so here's the preparation for it.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
`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.
The static row can be rare: many tables don't have them, and tables
that do will often have mutations without them (if the static row
is rarely updated, it may be present in the cache and in readers,
but absent in memtable mutations). However, it always consumes ~100
bytes of memory, even if it not present, due to row's overhead.
Change it to be optional by using lazy_row instead of row. Some call
sites treewide were adjusted to deal with the extra indirection.
perf_simple_query appears to improve by 2%, from 163krps to 165 krps,
though it's hard to be sure due to noisy measurements.
memory_footprint comparisons (before/after):
mutation footprint: mutation footprint:
- in cache: 1096 - in cache: 992
- in memtable: 854 - in memtable: 750
- in sstable: 351 - in sstable: 351
- frozen: 540 - frozen: 540
- canonical: 827 - canonical: 827
- query result: 342 - query result: 342
sizeof(cache_entry) = 112 sizeof(cache_entry) = 112
-- sizeof(decorated_key) = 36 -- sizeof(decorated_key) = 36
-- sizeof(cache_link_type) = 32 -- sizeof(cache_link_type) = 32
-- sizeof(mutation_partition) = 200 -- sizeof(mutation_partition) = 96
-- -- sizeof(_static_row) = 112 -- -- sizeof(_static_row) = 8
-- -- sizeof(_rows) = 24 -- -- sizeof(_rows) = 24
-- -- sizeof(_row_tombstones) = 40 -- -- sizeof(_row_tombstones) = 40
sizeof(rows_entry) = 232 sizeof(rows_entry) = 232
sizeof(lru_link_type) = 16 sizeof(lru_link_type) = 16
sizeof(deletable_row) = 168 sizeof(deletable_row) = 168
sizeof(row) = 112 sizeof(row) = 112
sizeof(atomic_cell_or_collection) = 8 sizeof(atomic_cell_or_collection) = 8
Tests: unit (dev)
Replace stdx::optional and stdx::string_view with the C++ std
counterparts.
Some instances of boost::variant were also replaced with std::variant,
namely those that called seastar::visit.
Scylla now requires GCC 8 to compile.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20190108111141.5369-1-duarte@scylladb.com>
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.
Until the cluster is fully upgraded from a version that uses the
incorrect counter shard ordering it is essential to keep using it lest
the old nodes corrupt the data upon receiving mutations with a counter
shard ordering they do not expect.
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
]
Range tombstones were introduced in version 1.3 and there exists
no direct upgrade from 1.2 to vnext, so we can retire the code
enforcing backwards compatibility.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20170614211654.82501-1-duarte@scylladb.com>
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>
write_{live, counter, expiring, dead}_cell() take a const reference to
an atomic cell as argument. However, their caller (which is
write_row_cells) passes to them an atomic_cell_view.
There is an appropriate implicit constructor so instead of compiler
complaints we get atomic_cell objects being constructed from views which
involves an allocation and a copy.
Message-Id: <20170213100106.9071-1-pdziepak@scylladb.com>
Original IDL generated code was hardcoded to always use bytes_ostream.
This patch makes the output stream a template parameter so that any
valid output stream can be used.
Unfortunately, making IDL writers generic requires updates in the code
that uses them, this is fixed in C++17 which would be able to deduce the
parameter in most cases.
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>
This patch introduces the range_tombstone class, composed of
a [start, end] pair of clustering_key_prefixes, the type
of inclusiveness of each bound, and a tombstone.
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>
Schema is tracked in memtable and cache per-entry. Entries are
upgraded lazily on access. Incoming mutations are upgraded to table's
current schema on given shard.
Mutating nodes need to keep schema_ptr alive in case schema version is
requested by target node.
write() will now write framing information. It will be needed when
serializing many mutations. The old version was left as
write_without_framing().
This change also makes the serializer interface closer to that of
db::serializer<>. To write an object, the serializer instance is
instantiated with the object and remembers the size, so that size
calculation doesn't have to be repeated again for write().
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.
