As requested in #22104, moved the files and fixed other includes and build system.
Moved files:
- combine.hh
- collection_mutation.hh
- collection_mutation.cc
- converting_mutation_partition_applier.hh
- converting_mutation_partition_applier.cc
- counters.hh
- counters.cc
- timestamp.hh
Fixes: #22104
This is a cleanup, no need to backport
Closesscylladb/scylladb#25085
Move mutation-related files to a new mutation/ directory. The names
are kept in the global namespace to reduce churn; the names are
unambiguous in any case.
mutation_reader remains in the readers/ module.
mutation_partition_v2.cc was missing from CMakeLists.txt; it's added in this
patch.
This is a step forward towards librarization or modularization of the
source base.
Closes#12788
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
When compacting a mutation fragment stream (e.g. for sstable
compaction, data query, repair), the compactor needs to accumulate
range tombstones which are relevant for the yet-to-be-processed range.
See range_tombstone_accumulator. One problem is that it has unbounded
memory footprint because the accumulator needs to keep track of all
the tombstoned ranges which are still active.
Another, although more benign, problem is computational complexity
needed to maintain that data structure.
The fix is to get rid of the overlap of range tombstones in the
mutation fragment stream. In v2 of the stream, there is no longer a
range_tombstone fragment. Deletions of ranges of rows within a given
partition are represented with range_tombstone_change fragments. At
any point in the stream there is a single active clustered
tombstone. It is initially equal to the neutral tombstone when the
stream of each partition starts. The range_tombstone_change fragment
type signify changes of the active clustered tombstone. All fragments
emitted while a given clustered tombstone is active are affected by
that tombstone. Like with the old range_tombstone fragments, the
clustered tombstone is independent from the partition tombstone
carried in partition_start.
The v2 stream is strict about range tombstone trimming. It emits range
tombstone changes which reflect range tombstones trimmed to query
restrictions, and fast-forwarding ranges. This makes the stream more
canonical, meaning that for a given set of writes, querying the
database should produce the same stream of fragments for a given
restrictions. There is less ambiguity in how the writes are
represented in the fragment stream. It wasn't the case with v1. For
example, A given set of deletions could be produced either as one
range_tombstone, or may, split and/or deoverlapped with other
fragments. Making a stream canonical is easier for diff-calculating.
The classes related to mutation fragment streams were cloned:
flat_mutation_reader_v2, mutation_fragment_v2, and related concepts.
Refs #8625.
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.
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>
This type of mutation_fragment will be used in new mutation_reader
to signal the end of the current partition.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
This type of mutation_fragment will be used in new mutation_reader
to signal the beginning of the next partition.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
