The `compaction_strategy_state` class holds strategy specific state via
a `std::variant` containing different state types. When a compaction
strategy performs compaction, it retrieves a reference to its state from
the `compaction_strategy_state` object. If the table's compaction
strategy is ALTERed while a compaction is in progress, the
`compaction_strategy_state` object gets replaced, destroying the old
state. This leaves the ongoing compaction holding a dangling reference,
resulting in a use after free.
Fix this by using `seastar::shared_ptr` for the state variant
alternatives(`leveled_compaction_strategy_state_ptr` and
`time_window_compaction_strategy_state_ptr`). The compaction strategies
now hold a copy of the shared_ptr, ensuring the state remains valid for
the duration of the compaction even if the strategy is altered.
The `compaction_strategy_state` itself is still passed by reference and
only the variant alternatives use shared_ptrs. This allows ongoing
compactions to retain ownership of the state independently of the
wrapper's lifetime.
Fixes#25913
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
During TWCS compaction, multiple methods independently fetch the
compaction_strategy_state using get_state(). This can lead to
inconsistencies if the compaction strategy is ALTERed while the
compaction is in progress.
This patch fixes a part of this issue by passing down the state to the
lower level methods as parameters instead of fetching it repeatedly.
Refs #25913
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Various compaction strategies still have their respective
make_sstable_set() implementation in sstables/sstable_set.cc. Move them
to the appropriate .cc files in compaction/, making the compaction
module more self contained.
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.
This will allow upcoming work to gently produce a sstable set for
each compaction group view. Example: repaired and unrepaired.
Locking strategy for compaction's sstable selection:
Since sstable retrieval path became futurized, tasks in compaction
manager will now hold the write lock (compaction_state::lock)
when retrieving the sstable list, feeding them into compaction
strategy, and finally registering selected sstables as compacting.
The last step prevents another concurrent task from picking the
same sstable. Previously, all those steps were atomic, but
we have seen stall in that area in large installations, so
futurization of that area would come sooner or later.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Since table_state is a view to a compaction group, it makes sense
to rename it as so.
With upcoming incremental repair, each replica::compaction_group
will be actually two compaction groups, so there will be two
views for each replica::compaction_group.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Replace boost::range::find() calls with std::ranges::find(). This
change reduces external dependencies and modernizes the codebase.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22942
Replace boost::range::remove_if() with the standard library's
std::ranges::remove_if() to reduce external dependencies and simplify
the codebase. This change eliminates the requirement for boost::range
and makes the implementation more maintainable.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
in order to reduce the external header dependency, let's switch to
the standardlized std::ranges::min_element().
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22572
now that we are allowed to use C++23. we now have the luxury of using
`std::ranges::to`.
in this change, we:
- replace `boost::copy_range` to `std::ranges::to`
- remove unused `#include` of boost headers
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21880
now that we are allowed to use C++23. we now have the luxury of using
`std::views::transform`.
in this change, we:
- replace `boost::adaptors::transformed` with `std::views::transform`
- use `fmt::join()` when appropriate where `boost::algorithm::join()`
is not applicable to a range view returned by `std::view::transform`.
- use `std::ranges::fold_left()` to accumulate the range returned by
`std::view::transform`
- use `std::ranges::fold_left()` to get the maximum element in the
range returned by `std::view::transform`
- use `std::ranges::min()` to get the minimal element in the range
returned by `std::view::transform`
- use `std::ranges::equal()` to compare the range views returned
by `std::view::transform`
- remove unused `#include <boost/range/adaptor/transformed.hpp>`
- use `std::ranges::subrange()` instead of `boost::make_iterator_range()`,
to feed `std::views::transform()` a view range.
to reduce the dependency to boost for better maintainability, and
leverage standard library features for better long-term support.
this change is part of our ongoing effort to modernize our codebase
and reduce external dependencies where possible.
limitations:
there are still a couple places where we are still using
`boost::adaptors::transformed` due to the lack of a C++23 alternative
for `boost::join()` and `boost::adaptors::uniqued`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21700
since chrono allows dividion between durations with different units. let
use it instead for rounding down to the nearest multiple of the window
size, for better readability.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#20476
Currently, `estimated_pending_compactions` uses a precalculated value
calculated by `update_estimated_compaction_by_tasks`, which, in turn,
is called by `get_compaction_candidates`. That means that, if
`estimated_pending_compactions` is called, e.g. right after
major compaction, it will return an outdated value that was
calculated prior to major compaction, and so, it is no longer
relevant.
Instead, just recalculate the value in `estimated_pending_compactions`
and drop `update_estimated_compaction_by_tasks`.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Using the standard library is preffered over boost.
In cql3/expr/expression.cc to_sorted_vector got more of a
face-list and was modernized to use also std::unique
and while at it, to move its input range in the uniquely sorted
result vector.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently the function calls boost::partial_sort with a middle
iterator that might be out of bound and cause undefined behavior.
Check the vector size, and do a partial sort only if its longer
than `max_sstables`, otherwise sort the whole vector.
Fixesscylladb/scylladb#20608
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#20609
flat_mutation_reader_v2 was introduced in a pair of commits in 2021:
e3309322c3 "Clone flat_mutation_reader related classes into v2 variants"
08b5773c12 "Adapt flat_mutation_reader_v2 to the new version of the API"
as a replacement for flat_mutation_reader, using range_tombstone_change
instead of range_tombstone to represent represent range tombstones. See
those commits for more information.
The transition was incremental; the last use of the original
flat_mutation_reader was removed in 2022 in commit
026f8cc1e7 "db: Use mutation_partition_v2 in mvcc"
In turn, flat_mutation_reader was introduced in 2017 in commit
748205ca75 "Introduce flat_mutation_reader"
To transition from a mutation_reader that nested rows within
a partition in a separate stream, to a flat reader that streamed
partitions and rows in the same stream.
Here, we reclaim the original name and rename the awkward
flat_mutation_reader_v2 to mutation_reader.
Note that mutation_fragment_v2 remains since we still use the original
for compatibilty, sometimes.
Some notes about the transition:
- files were also renamed. In one case (flat_mutation_reader_test.cc), the
rename target already existed, so we rename to
mutation_reader_another_test.cc.
- a namespace 'mutation_reader' with two definitions existed (in
mutation_reader_fwd.hh). Its contents was folded into the mutation_reader
class. As a result, a few #includes had to be adjusted.
Closesscylladb/scylladb#19356
TWCS off-strategy suffers with 100% space overhead, so a big TWCS table
can cause scylla to run out of disk space during node ops.
To not penalize TWCS tables, that take a small percentage of disk,
with increased write ampl, TWCS off-strategy will be restricted to
10% of free disk space. Then small tables can still compact all
disjoint sstables in a single round.
Fixes#16514.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
reader_consumer_v2 being a noncopyable_function imposes a restriction
when stacking one interposer consumer on top of another.
Think for example of a token-based segregator on top of a timestamp
based one.
To achieve that, the interposer consumer creator must be reentrant,
such that the consumer can be created on each "channel", but today
the creator becomes unusable after first usage.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
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 a formatter for
map<timestamp_type, vector<shared_sstable>>. since the operator<<
for this type is only used in the .cc file, and the only use case
of it is to provide the formatter for fmt, so the operator<< based
formatter is remove in this change.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#16163
When off-strategy is disabled, data segregation is not postponed,
meaning that getting partition estimate right is important to
decrease filter's false positives. With streaming, we don't
have min and max timestamps at destination, well, we could have
extended the RPC verb to send them, but turns out we can deduce
easily the amount of windows using default TTL. Given partitioner
random nature, it's not absurd to assume that a given range being
streamed may overlap with all windows, meaning that each range
will yield one sstable for each window when segregating incoming
data. Today, we assume the worst of 100 windows (which is the
max amount of sstables the input data can be segregated into)
due to the lack of metadata for estimating the window count.
But given that users are recommended to target a max of ~20
windows, it means partition estimate is being downsized 5x more
than needed. Let's improve it by using default TTL when
estimating window count, so even on absence of timestamp
metadata, the partition estimation won't be way off.
Fixes#15704.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
After "repair: Get rid of the gc_grace_seconds", the sstable's schema (mode,
gc period if applicable, etc) is used to estimate the amount of droppable
data (or determine full expiration = max_deletion_time < gc_before).
It could happen that the user switched from timeout to repair mode, but
sstables will still use the old mode, despite the user asked for a new one.
Another example is when you play with value of grace period, to prevent
data resurrection if repair won't be able to run in a timely manner.
The problem persists until all sstables using old GC settings are recompacted
or node is restarted.
To fix this, we have to feed latest schema into sstable procedures used
for expiration purposes.
Fixes#15643.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closesscylladb/scylladb#15746
Now everything is prepared for the switch, let's do it.
Now let's wait for ICS to enjoy the set of changes.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
To be consistent with other compaction_strategy_options,
time_window_compaction_strategy_options uses compaction_strategy_impl::get_value
and cql3::statements::property_definitions::to_long helpers for
parsing.
Add temporarily empty validate method to compaction_strategy_options.
The method will validate the options and help determining whether
only the allowed options were set.
Prevent switch case statements from falling through without annotation
([[fallthrough]]) proving that this was intended.
Existing intended cases were annotated.
Closes#14607
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
compaction strategies know how to pick files that are most likely to
satisfy tombstone purge conditions (i.e. not shadow data in uncompacting
files).
This logic can be bypassed if tombstone GC was disabled by user,
as it's a waste of effort to proceed with it until re-enabled.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
enable_optimized_twcs_queries is specific to TWCS, therefore it
belongs to TWCS, not replica::table.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closes#13489
TWCS no longer keeps internal state, and will now rely on state
managed by each compaction group through compaction::table_state.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
This is a step towards decoupling compaction strategy (computation)
and its state. Making the former stateless.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
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
This series introduces two configurable options when working with TWCS tables:
- `restrict_twcs_default_ttl` - a LiveUpdate-able tri_mode_restriction which defaults to WARN and will notify the user whenever a TWCS table is created without a `default_time_to_live` setting
- `twcs_max_window_count` - Which forbids the user from creating TWCS tables whose window count (buckets) are past a certain threshold. We default to 50, which should be enough for most use cases, and a setting of 0 effectively disables the check.
Refs: #6923Fixes: #9029Closes#11445
* github.com:scylladb/scylladb:
tests: cql_query_test: add mixed tests for verifying TWCS guard rails
tests: cql_query_test: add test for TWCS window size
tests: cql_query_test: add test for TWCS tables with no TTL defined
cql: add configurable restriction of default_time_to_live when for TimeWindowCompactionStrategy tables
cql: add max window restriction for TimeWindowCompactionStrategy
time_window_compaction_strategy: reject invalid window_sizes
cql3 - create/alter_table_statement: Make check_restricted_table_properties accept a schema_ptr
Scylla mistakenly allows an user to configure an invalid TWCS window_size <= 0, which effectively breaks the notion of compaction windows.
Interestingly enough, a <= 0 window size should be considered an undefined behavior as either we would create a new window every 0 duration (?) or the table would behave as STCS, the reader is encouraged to figure out which one of these is true. :-)
Cassandra, on the other hand, will properly throw a ConfigurationException when receiving such invalid window sizes and we now match the behavior to the same as Cassandra's.
Refs: #2336
