This pull request adds support for calculation and storing CRC32 digests for all SSTable components.
This change replaces plain file_writer with crc32_digest_file_writer for all SSTable components that should be checksummed. The resulting component digests are stored in the sstable structure
and later persisted to disk as part of the Scylla metadata component during writer::consume_end_of_stream.
Several test cases where introduced to verify expected behaviour.
Additionally, this PR adds new rewrite component mechanism for safe sstable component rewriting.
Previously, rewriting an sstable component (e.g., via rewrite_statistics) created a temporary file that was renamed to the final name after sealing. This allowed crash recovery by simply removing the temporary file on startup.
However, with component digests stored in scylla_metadata (#20100),
replacing a component like Statistics requires atomically updating both the component
and scylla_metadata with the new digest - impossible with POSIX rename.
The new mechanism creates a clone sstable with a fresh generation:
- Hard-links all components from the source except the component being rewritten and scylla_metadata
- Copies original sstable components pointer and recognized components from the source
- Invokes a modifier callback to adjust the new sstable before rewriting
- Writes the modified component along with updated scylla_metadata containing the new digest
- Seals the new sstable with a temporary TOC
- Replaces the old sstable atomically, the same way as it is done in compaction
This is built on the rewrite_sstables compaction framework to support batch operations (e.g., following incremental repair).
In case of any failure durning the whole process, sstable will be automatically deleted on the node startup due to
temporary toc persistence.
Backport is not required, it is a new feature
Fixes https://github.com/scylladb/scylladb/issues/20100, https://github.com/scylladb/scylladb/issues/27453Closesscylladb/scylladb#28338
* github.com:scylladb/scylladb:
docs: document components_digests subcomponent and trailing digest in Scylla.db
sstable_compaction_test: Add tests for perform_component_rewrite
sstable_test: add verification testcases of SSTable components digests persistance
sstables: store digest of all sstable components in scylla metadata
sstables: replace rewrite_statistics with new rewrite component mechanism
sstables: add new rewrite component mechanism for safe sstable component rewriting
compaction: add compaction_group_view method to specify sstable version
sstables: add null_data_sink and serialized_checksum for checksum-only calculation
sstables: extract default write open flags into a constant
sstables: Add write_simple_with_digest for component checksumming
sstables: Extract file writer closing logic into separate methods
sstables: Implement CRC32 digest-only writer
Instead of dht::partition_ranges_vector, which is an std::vector<> and
have been seen to cause large allocations when calculating ranges to be
invalidated after compaction:
seastar_memory - oversized allocation: 147456 bytes. This is non-fatal, but could lead to latency and/or fragmentation issues. Please report: at
[Backtrace #0]
void seastar::backtrace<seastar::current_backtrace_tasklocal()::$_0>(seastar::current_backtrace_tasklocal()::$_0&&, bool) at ./build/release/seastar/./seastar/include/seastar/util/backtrace.hh:89
(inlined by) seastar::current_backtrace_tasklocal() at ./build/release/seastar/./seastar/src/util/backtrace.cc:99
seastar::current_tasktrace() at ./build/release/seastar/./seastar/src/util/backtrace.cc:136
seastar::current_backtrace() at ./build/release/seastar/./seastar/src/util/backtrace.cc:169
seastar::memory::cpu_pages::warn_large_allocation(unsigned long) at ./build/release/seastar/./seastar/src/core/memory.cc:840
seastar::memory::cpu_pages::check_large_allocation(unsigned long) at ./build/release/seastar/./seastar/src/core/memory.cc:903
(inlined by) seastar::memory::cpu_pages::allocate_large(unsigned int, bool) at ./build/release/seastar/./seastar/src/core/memory.cc:910
(inlined by) seastar::memory::allocate_large(unsigned long, bool) at ./build/release/seastar/./seastar/src/core/memory.cc:1533
(inlined by) seastar::memory::allocate_slowpath(unsigned long) at ./build/release/seastar/./seastar/src/core/memory.cc:1679
seastar::memory::allocate(unsigned long) at ././seastar/src/core/memory.cc:1698
(inlined by) operator new(unsigned long) at ././seastar/src/core/memory.cc:2440
(inlined by) std::__new_allocator<interval<dht::ring_position>>::allocate(unsigned long, void const*) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/new_allocator.h:151
(inlined by) std::allocator<interval<dht::ring_position>>::allocate(unsigned long) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/allocator.h:203
(inlined by) std::allocator_traits<std::allocator<interval<dht::ring_position>>>::allocate(std::allocator<interval<dht::ring_position>>&, unsigned long) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/alloc_traits.h:614
(inlined by) std::_Vector_base<interval<dht::ring_position>, std::allocator<interval<dht::ring_position>>>::_M_allocate(unsigned long) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/stl_vector.h:387
(inlined by) std::vector<interval<dht::ring_position>, std::allocator<interval<dht::ring_position>>>::reserve(unsigned long) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/vector.tcc:79
dht::to_partition_ranges(utils::chunked_vector<interval<dht::token>, 131072ul> const&, seastar::bool_class<utils::can_yield_tag>) at ./dht/i_partitioner.cc:347
compaction::compaction::get_ranges_for_invalidation(std::vector<seastar::lw_shared_ptr<sstables::sstable>, std::allocator<seastar::lw_shared_ptr<sstables::sstable>>> const&) at ./compaction/compaction.cc:619
(inlined by) compaction::compaction::get_compaction_completion_desc(std::vector<seastar::lw_shared_ptr<sstables::sstable>, std::allocator<seastar::lw_shared_ptr<sstables::sstable>>>, std::vector<seastar::lw_shared_ptr<sstables::sstable>, std::allocator<seastar::lw_shared_ptr<sstables::sstable>>>) at ./compaction/compaction.cc:719
(inlined by) compaction::regular_compaction::replace_remaining_exhausted_sstables() at ./compaction/compaction.cc:1362
compaction::compaction::finish(std::chrono::time_point<db_clock, std::chrono::duration<long, std::ratio<1l, 1000l>>>, std::chrono::time_point<db_clock, std::chrono::duration<long, std::ratio<1l, 1000l>>>) at ./compaction/compaction.cc:1021
compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0::operator()() at ./compaction/compaction.cc:1960
(inlined by) compaction::compaction_result std::__invoke_impl<compaction::compaction_result, compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>(std::__invoke_other, compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/invoke.h:63
(inlined by) std::__invoke_result<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>::type std::__invoke<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>(compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/bits/invoke.h:98
(inlined by) decltype(auto) std::__apply_impl<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0, std::tuple<>>(compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&, std::tuple<>&&, std::integer_sequence<unsigned long, ...>) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/tuple:2920
(inlined by) decltype(auto) std::apply<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0, std::tuple<>>(compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&, std::tuple<>&&) at /usr/lib/gcc/x86_64-redhat-linux/15/../../../../include/c++/15/tuple:2935
(inlined by) seastar::future<compaction::compaction_result> seastar::futurize<compaction::compaction_result>::apply<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>(compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&, std::tuple<>&&) at ././seastar/include/seastar/core/future.hh:1930
(inlined by) seastar::futurize<std::invoke_result<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>::type>::type seastar::async<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>(seastar::thread_attributes, compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&)::'lambda'()::operator()() const at ././seastar/include/seastar/core/thread.hh:267
(inlined by) seastar::noncopyable_function<void ()>::direct_vtable_for<seastar::futurize<std::invoke_result<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>::type>::type seastar::async<compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0>(seastar::thread_attributes, compaction::compaction::run(std::unique_ptr<compaction::compaction, std::default_delete<compaction::compaction>>)::$_0&&)::'lambda'()>::call(seastar::noncopyable_function<void ()> const*) at ././seastar/include/seastar/util/noncopyable_function.hh:138
seastar::noncopyable_function<void ()>::operator()() const at ./build/release/seastar/./seastar/include/seastar/util/noncopyable_function.hh:224
(inlined by) seastar::thread_context::main() at ./build/release/seastar/./seastar/src/core/thread.cc:318
dht::partition_ranges_vector is used on the hot path, so just convert
the problematic user -- cache invalidation -- to use
utils::chunked_vector<dht::partition_range> instead.
Fixes: SCYLLADB-121
Closesscylladb/scylladb#28855
Previously, rewriting an sstable component (e.g., via rewrite_statistics) created a temporary file that was renamed
to the final name after sealing. This allows crash recovery by simply removing the temporary file on startup.
However, this approach won't work once component digests are stored in scylla_metadata,
as replacing a component like Statistics will require atomically updating both the component
and scylla_metadata with the new digest—impossible with POSIX rename.
The new mechanism creates a clone sstable with a fresh generation:
- Hard-links all components from the source except the component being rewritten and scylla metadata if update_sstable_id is true
- Copies original sstable components pointer and recognized components from the source
- Invokes a modifier callback to adjust the new sstable before rewriting
- Writes the modified component. If update_sstable_id is true, reads scylla metadata, generates new sstable_id and rewrites it.
- Seals the new sstable with a temporary TOC
- Replaces the old sstable atomically, the same way as it is done in compaction
This is built on the rewrite_sstables compaction framework to support batch operations (e.g., following incremental repair).
In case of any failure during the whole process, sstable will be automatically deleted on the node startup due to
temporary toc persistence.
This prepares the infrastructure for component digests. Once digests are introduced in scylla_metadata
this mechanism will be extended to also rewrite scylla metadata with the updated digest alongside the modified component, ensuring atomic updates of both.
Introduce a new compaction_type enum : `Major`.
This type will be used by the next patches to differentiate between
major compaction and regular compaction (compaction_type::Compaction).
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
This patch adds a new flag `drop-unfixable-sstables` to the scrub operation
in segregate mode, allowing to automatically drop SSTables that
cannot be fixed during scrub. It also includes API support of the 'drop_unfixable_sstables'
paramater and validation to ensure this flag is not enabled in other modes rather than segragate.
The namespace usage in this directory is very inconsistent, with files
and classes scattered in:
* global namespace
* namespace compaction
* namespace sstables
With cases, where all three used in the same file. This code used to
live in sstables/ and some of it still retains namespace sstables as a
heritage of that time. The mismatch between the dir (future module) and
the namespace used is confusing, so finish the migration and move all
code in compaction/ to namespace compaction too.
This patch, although large, is mechanic and only the following kind of
changes are made:
* replace namespace sstable {} with namespace compaction {}
* add namespace compaction {}
* drop/add sstables::
* drop/add compaction::
* move around forward-declarations so they are in the correct namespace
context
This refactoring revealed some awkward leftover coupling between
sstables and compaction, in sstables/sstable_set.cc, where the
make_sstable_set() methods of compaction strategies are implemented.
Added new option, `gc_check_only_compacting_sstables`, to
compaction_descriptor to control the garbage collection behavior. The
subsequent patches will use this flag to decide if the garbage
collection has to check only the SSTables being compacted to collect
tombstones. This option is disabled for now and will be enabled based on
a new compaction parameter that will be added later in this patch
series.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
in in {fmt} before v10, it provides the specialization of `fmt::formatter<..>`
for `std::string_view` as well as the specialization of `fmt::formatter<..>`
for `fmt::string_view` which is an implementation builtin in {fmt} for
compatibility of pre-C++17. and this type is used even if the code is
compiled with C++ stadandard greater or equal to C++17. also, before v10,
the `fmt::formatter<std::string_view>::format()` is defined so it accepts
`std::string_view`. after v10, `fmt::formatter<std::string_view>` still
exists, but it is now defined using `format_as()` machinery, so it's
`format()` method does not actually accept `std::string_view`, it
accepts `fmt::string_view`, as the former can be converted to
`fmt::string_view`.
this is why we can inherit from `fmt::formatter<std::string_view>` and
use `formatter<std::string_view>::format(foo, ctx);` to implement the
`format()` method with {fmt} v9, but we cannot do this with {fmt} v10,
and we would have following compilation failure:
```
FAILED: service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o
/home/kefu/.local/bin/clang++ -DFMT_DEPRECATED_OSTREAM -DFMT_SHARED -DSCYLLA_BUILD_MODE=release -DSEASTAR_API_LEVEL=7 -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SSTRING -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"RelWithDebInfo\" -I/home/kefu/dev/scylladb -I/home/kefu/dev/scylladb/build/gen -I/home/kefu/dev/scylladb/seastar/include -I/home/kefu/dev/scylladb/build/seastar/gen/include -I/home/kefu/dev/scylladb/build/seastar/gen/src -ffunction-sections -fdata-sections -O3 -g -gz -std=gnu++20 -fvisibility=hidden -Wall -Werror -Wextra -Wno-error=deprecated-declarations -Wimplicit-fallthrough -Wno-c++11-narrowing -Wno-deprecated-copy -Wno-mismatched-tags -Wno-missing-field-initializers -Wno-overloaded-virtual -Wno-unsupported-friend -Wno-enum-constexpr-conversion -Wno-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb=. -march=westmere -mllvm -inline-threshold=2500 -fno-slp-vectorize -U_FORTIFY_SOURCE -Werror=unused-result -MD -MT service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -MF service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o.d -o service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -c /home/kefu/dev/scylladb/service/topology_state_machine.cc
/home/kefu/dev/scylladb/service/topology_state_machine.cc:254:41: error: no matching member function for call to 'format'
254 | return formatter<std::string_view>::format(it->second, ctx);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
/usr/include/fmt/core.h:2759:22: note: candidate function template not viable: no known conversion from 'seastar::basic_sstring<char, unsigned int, 15>' to 'const fmt::basic_string_view<char>' for 1st argument
2759 | FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
| ^ ~~~~~~~~~~~~
```
because the inherited `format()` method actually comes from
`fmt::formatter<fmt::string_view>`. to reduce the confusion, in this
change, we just inherit from `fmt::format<string_view>`, where
`string_view` is actually `fmt::string_view`. this follows
the document at
https://fmt.dev/latest/api.html#formatting-user-defined-types,
and since there is less indirection under the hood -- we do not
use the specialization created by `FMT_FORMAT_AS` which inherit
from `formatter<fmt::string_view>`, hopefully this can improve
the compilation speed a little bit. also, this change addresses
the build failure with {fmt} v10.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18299
before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
in this change, we define formatters for
* `sstables::compaction_type`
* `sstables::compaction_type_options::scrub::mode`
* `sstables::compaction_type_options::scrub::quarantine_mode``
and drop their operator<<:s.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17441
Scylla sstable promises to *never* mutate its input sstables. This
promise was broken by `scylla sstable scrub --scrub-mode=validate`,
because validate moves invalid input sstables into qurantine. This is
unexpected and caused occasional failures in the scrub tests in
test_tools.py. Fix by propagating a flag down to
`scrub_sstables_validate_mode()` in `compaction.cc`, specifying whether
validate should qurantine invalid sstables, then set this flag to false
in `scylla-sstable.cc`. The existing test for validate-mode scrub is
ammended to check that the sstable is not mutated. The test now fails
before the fix and passes afterwards.
Fixes: #14309Closes#15139
for faster build times and clear inter-module dependencies, we
should not #includes headers not directly used. instead, we should
only #include the headers directly used by a certain compilation
unit.
in this change, the source files under "/compaction" directories
are checked using clangd, which identifies the cases where we have
an #include which is not directly used. all the #includes identified
by clangd are removed. because some source files rely on the incorrectly
included header file, those ones are updated to #include the header
file they directly use.
if a forward declaration suffice, the declaration is added instead.
see also https://clangd.llvm.org/guides/include-cleaner#unused-include-warning
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
In that level no io_priority_class-es exist. Instead, all the IO happens
in the context of current sched-group. File API no longer accepts prio
class argument (and makes io_intent arg mandatory to impls).
So the change consists of
- removing all usage of io_priority_class
- patching file_impl's inheritants to updated API
- priority manager goes away altogether
- IO bandwidth update is performed on respective sched group
- tune-up scylla-gdb.py io_queues command
The first change is huge and was made semi-autimatically by:
- grep io_priority_class | default_priority_class
- remove all calls, found methods' args and class' fields
Patching file_impl-s is smaller, but also mechanical:
- replace io_priority_class& argument with io_intent* one
- pass intent to lower file (if applicatble)
Dropping the priority manager is:
- git-rm .cc and .hh
- sed out all the #include-s
- fix configure.py and cmakefile
The scylla-gdb.py update is a bit hairry -- it needs to use task queues
list for IO classes names and shares, but to detect it should it checks
for the "commitlog" group is present.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closes#13963
So it can be used in the next patch that will refactor
compaction_state out of class compaction_manager.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move the owned_ranges_ptr, currently used only by
cleanup and upgrade compactions, to the generic
compaction descriptor so we apply cleanup in other
compaction types.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Adds support for splitting large partitions during compaction.
Large partitions introduce many problems, like memory overhead and
breaks incremental compaction promise. We want to split large
partitions across fixed-size fragments. We'll allow a partition
to exceed size limit by 10%, as we don't want to unnecessarily split
partitions that just crossed the limit boundary.
To avoid having to open a minimal of 2 fragments in a read, partition
tombstone will be replicated to every fragment storing the
partition.
The splitting isn't enabled by default, and can be used by
strategies that are run aware like ICS. LCS still cannot support
it as it's still using physical level metadata, not run id.
An incremental reader for sstable runs will follow soon.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Currently they are copied for the get_sstables function
so this change reduces copies.
Also, it will allow further decoupling of compaction_manager
from replica::database, by letting the caller of
perform_cleanup and perform_sstable_upgrade get the
owned token ranges from db and pass it to the perform_*
functions in the following patch.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
For compaction to be able to purge expired data, like tombstones, a
sstable set snapshot is set in the compaction descriptor.
That's a decision that belongs to task type. For example, all regular
compaction enable GC, whereas scrub for example doesn't for safety
reasons.
The problem is that the decision is being made by every instantiation
of compaction_descriptor in the strategies, which is both unnecessary
and also adds lots of boilerplate to the code, making it hard to
understand and work with.
As sstable set snapshot is an implementation detail, a new method
is being added to compaction_descriptor to make the intention
clearer, making the interface easier to understand.
can_purge_tombstones, used previously by rewrite task only, is being
reused for communicating GC intention into task::compact_sstables().
The boilerplate was a pain when adding a new strategy method for
the ongoing work on cleanup, described by issue #10097.
Another benefit is that we'll now only create a set snapshot when
compaction will really run. Before, it could happen that the snapshot
would be discarded if the compaction attempt had to be postponed,
which is a waste of cpu cycles.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
With compact_sstables() now living in compaction_manager::task,
release_exhausted no longer has to live inside compaction_descriptor,
which is a good direction because implementation detail is being
removed from the interface.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20220311023410.250149-2-raphaelsc@scylladb.com>
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
Compaction efficiency can be defined as how much backlog is reduced per
byte read or written.
We know a few facts about efficiency:
1) the more files are compacted together (the fan-in) the higher the
efficiency will be, however...
2) the bigger the size difference of input files the worse the
efficiency, i.e. higher write amplification.
so compactions with similar-sized files are the most efficient ones,
and its efficiency increases with a higher number of files.
However, in order to not have bad read amplification, number of files
cannot grow out of bounds. So we have to allow parallel compaction
on different tiers, but to avoid "dilution" of overall efficiency,
we will only allow a compaction to proceed if its efficiency is
greater than or equal to the efficiency of ongoing compactions.
By the time being, we'll assume that strategies don't pick candidates
with wildly different sizes, so efficiency is only calculated as a
function of compaction fan-in.
Now when system is under heavy load, then fan-in threshold will
automatically grow to guarantee that overall efficiency remains
stable.
Please note that fan-in is defined in number of runs. LCS compaction
on higher levels will have a fan-in of 2. Under heavy load, it
may happen that LCS will temporarily switch to size-tiered mode
for compaction to keep up with amount of data being produced.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20211103215110.135633-2-raphaelsc@scylladb.com>
It's much more efficient to have a separate compaction task that consists
completely from expired sstables and make sure it gets a unique "weight" than
mixing expired sstables with non-expired sstables adding an unpredictable
latency to an eviction event of an expired sstable.
This change also improves the visibility of eviction events because now
they are always going to appear in the log as compactions that compact into
an empty set.
Fixes#9533
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
Closes#9534
So they can be easily computed using an async task
before constructing the compaction object
in a following patch.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
the name compaction_options is confusing as it overlaps in meaning
with compaction_descriptor. hard to reason what are the exact
difference between them, without digging into the implementation.
compaction_options is intended to only carry options specific to
a give compaction type, like a mode for scrub, so let's rename
it to compaction_type_options to make it clearer for the
readers.
[avi: adjust for scrub changes]
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210908003934.152054-1-raphaelsc@scylladb.com>
Since compaction is layered on top of sstables, let's move all compaction code
into a new top-level directory.
This change will give me extra motivation to remove all layer violations, like
sstable calling compaction-specific code, and compaction entanglement with
other components like table and storage service.
Next steps:
- remove all layer violations
- move compaction code in sstables namespace into a new one for compaction.
- move compaction unit tests into its own file
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20210707194058.87060-1-raphaelsc@scylladb.com>
