This function was obsoleted by schema_builder some time ago. Not to patch all its callers, that helper became wrapper around it. Remained users are all in tests, and patching the to use builder directory makes the code shorter in many cases.
Closesscylladb/scylladb#20466
* github.com:scylladb/scylladb:
schema: Ditch make_shared_schema() helper
test: Tune up indentation in uncompressed_schema()
test: Make tests use schema_builder instead of make_shared_schema
When purging regular tombstone consult the min_live_timestamp,
if available.
For shadowable_tombstones, consult the
min_memtable_live_row_marker_timestamp,
if available, otherwise fallback to the min_live_timestamp.
If both are missing, fallback to the legacy
(and inaccurate) min_timestamp.
Fixesscylladb/scylladb#20423Fixesscylladb/scylladb#20424
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Before we add a new, is_shadowable, parameter to it.
And define global `can_always_purge` and `can_never_purge`
functions, a-la `always_gc` and `never_gc`.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
And define `never_gc` globally, same as `always_gc`
Before adding a new, is_shadowable parameter to it.
Since it is used in the context of compaction
it better fits compaction_garbage_collector header
rather than tombstone.hh
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Everything, but perf test is straightforward switch.
The perf-test generated regular columns dynamically via vector, with
builder the vector goes away.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The reverse parameter is no longer used with native reverse reads.
The row ranges are provided in native reverse order together with
a reversed schema, thus the reverse parameter remain false all the
time and can be droped.
Having an operator bool() on this struct is counter-intuitive, so this
commit drops it and migrates any remaining users to bool is_live().
The purpose of this operator bool() was to help in incrementally replace
the previous bool return type with compact_and_expire_result in the
compact_and_expire() call stack. Now that this is done, it has served
its purpose.
assert() is traditionally disabled in release builds, but not in
scylladb. This hasn't caused problems so far, but the latest abseil
release includes a commit [1] that causes a 1000 insn/op regression when
NDEBUG is not defined.
Clearly, we must move towards a build system where NDEBUG is defined in
release builds. But we can't just define it blindly without vetting
all the assert() calls, as some were written with the expectation that
they are enabled in release mode.
To solve the conundrum, change all assert() calls to a new SCYLLA_ASSERT()
macro in utils/assert.hh. This macro is always defined and is not conditional
on NDEBUG, so we can later (after vetting Seastar) enable NDEBUG in release
mode.
[1] 66ef711d68Closesscylladb/scylladb#20006
Users outside of the token module don't
need to mess with the token::kind.
They can only create key tokens.
Never, minimum or maximum tokens, with a particular
datya value.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
It was added to make integration of storage groups easier, but it's
complicated since it's another source of truth and we could have
problems if it becomes inconsistent with the group map.
Fixes#18506.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
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
this change was created in the same spirit of 505900f18f. because
we are deprecating the operator<< for vector and unorderd_map in
Seastar, some tests do not compile anymore if we disable these
operators. so to be prepared for the change disabling them, let's
include test/lib/test_utils.hh for accessing the printer dedicated
for Boost.test. and also '#include <fmt/ranges.h>' when necessary,
because, in order to format the ranges using {fmt}, we need to
use fmt/ranges.h.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
The DIGEST_FOR_NULL_VALUES feature was added in 21a77612b3 (2020; 4.4)
and can now be assumed to be always present. The hasher which it invoked
is removed.
Currently, if the input mutation_partition requires
schema upgrade, apply_monotonically always silently reverts to
being non-preemptible, even if the caller passed is_preemptible::yes.
To prevent that from happening, put the burden of upgrading
the mutation_partition schem on the caller, which is
today the apply() methods, which are synchronous anyhow.
With that, we reduce the proliferation of the
`apply_monotonically` overloads and keep only the
low level one (which could potentially be private as well,
as it's called only from within the mutation/ source files
and from tests)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
The function splits the source mutation into multiple
mutations so that their size does not exceed the
max_size limit. The size of a mutation is calculated
as the sum of the memory_usage() of its constituent
mutation_fragments.
The implementation is taken from view_updating_consumer.
We use mutation_rebuilder_v2 to reconstruct mutations from
a stream of mutation fragments and recreate the output
mutation whenever we reach the limit.
We'll need this function in the next commit.
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 mutation_fragment_v2::printer
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Our interval template started life as `range`, and was supported
wrapping to follow Cassandra's convention of wrapping around the
maximum token.
We later recognized that an interval type should usually be non-wrapping
and split it into wrapping_range and nonwrapping_range, with `range`
aliasing wrapping_range to preserve compatibility.
Even later, we realized the name was already taken by C++ ranges and
so renamed it to `interval`. Given that intervals are usually non-wrapping,
the default `interval` type is non-wrapping.
We can now simplify it further, recognizing that everyone assumes
that an interval is non-wrapping and so doesn't need the
nonwrapping_interval_designation. We just rename nonwrapping_interval
to `interval` and remove the type alias.
range.hh was deprecated in bd794629f9 (2020) since its names
conflict with the C++ library concept of an iterator range. The name
::range also mapped to the dangerous wrapping_interval rather than
nonwrapping_interval.
Complete the deprecation by removing range.hh and replacing all the
aliases by the names they point to from the interval library. Note
this now exposes uses of wrapping intervals as they are now explicit.
The unit tests are renamed and range.hh is deleted.
Closesscylladb/scylladb#17428
get0() dates back from the days where Seastar futures carried tuples, and
get0() was a way to get the first (and usually only) element. Now
it's a distraction, and Seastar is likely to deprecate and remove it.
Replace with seastar::future::get(), which does the same thing.
Fixes some typos as found by codespell run on the code.
In this commit, I was hoping to fix only comments, not user-visible alerts, output, etc.
Follow-up commits will take care of them.
Refs: https://github.com/scylladb/scylladb/issues/16255
Signed-off-by: Yaniv Kaul <yaniv.kaul@scylladb.com>
We want to switch system.scylla_local table to the
schema commitlog, but load phases hamper here - schema
commitlog is initialized after phase1,
so a table which is using it should be moved to phase2,
but system.scylla_local contains features, and we need
them before schema commitlog initialization for
SCHEMA_COMMITLOG feature.
In this commit we are taking a different approach to
loading system tables. First, we load them all in
one pass in 'readonly' mode. In this mode, the table
cannot be written to and has not yet been assigned
a commit log. To achieve this we've added _readonly bool field
to the table class, it's initialized to true in table's
constructor. In addition, we changed the table constructor
to always assign nullptr to commitlog, and we trigger
an internal error if table.commitlog() property is accessed
while the table is in readonly mode. Then, after
triggering on_system_tables_loaded notifications on
feature_service and sstable_format_selector, we call
system_keyspace::mark_writable and eventually
table::mark_ready_for_writes which selects the
proper commitlog and marks the table as writable.
In sstable_compaction_test we drop several
mark_ready_for_writes calls since they are redundant,
the table has already been made writable in
env.make_table_for_tests call.
The table::commitlog function either returns the current
commitlog or causes an error if the table is readonly. This
didn't work for virtual tables, since they never called
mark_ready_for_writes. In this commit we add this
call to initialize_virtual_tables.
Greatly expand this test to check that the compactor validates the input
stream properly.
The test is renamed (the _sanity_test suffix is removed) to reflect the
expanded scope.
some times we initialize a loop variable like
auto i = 0;
or
int i = 0;
but since the type of `0` is `int`, what we get is a variable of
`int` type, but later we compare it with an unsigned number, if we
compile the source code with `-Werror=sign-compare` option, the
compiler would warn at seeing this. in general, this is a false
alarm, as we are not likely to have a wrong comparison result
here. but in order to prevent issues due to the integer promotion
for comparison in other places. and to prepare for enabling
`-Werror=sign-compare`. let's use unsigned to silence this warning.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
The test has about 1/2500000 chance to fail due to a conflict of random
values. And it recently did, just to spite us.
Fight back.
Fixes#14563Closes#14576
View update routines accept `mutation` objects.
But what comes out of staging sstable readers is a stream of
mutation_fragment_v2 objects.
To build view updates after a repair/streaming, we have to
convert the fragment stream into `mutation`s. This is done by piping
the stream to mutation_rebuilder_v2.
To keep memory usage limited, the stream for a single partition might
have to be split into multiple partial `mutation` objects.
view_update_consumer does that, but in improper way -- when the
split/flush happens inside an active range tombstone, the range
tombstone isn't closed properly. This is illegal, and triggers an
internal error.
This patch fixes the problem by closing the active range tombstone
(and reopening in the same position in the next `mutation` object).
The tombstone is closed just after the last seen clustered position.
This is not necessary for correctness -- for example we could delay
all processing of the range tombstone until we see its end
bound -- but it seems like the most natural semantic.
Fixes#14503
Currently, when two cells have the same write timestamp
and both are alive or expiring, we compare their value first,
before checking if either of them is expiring
and if both are expiring, comparing their expiration time
and ttl value to determine which of them will expire
later or was written later.
This was changed in CASSANDRA-14592
for consistency with the preference for dead cells over live cells,
as expiring cells will become tombstones at a future time
and then they'd win over live cells with the same timestamp,
hence they should win also before expiration.
In addition, comparing the cell value before expiration
can lead to unintuitive corner cases where rewriting
a cell using the same timestamp but different TTL
may cause scylla to return the cell with null value
if it expired in the meanwhile.
Also, when multiple columns are written using two upserts
using the same write timestamp but with different expiration,
selecting cells by their value may return a mixed result
where each cell is selected individually from either upsert,
by picking the cells with the largest values for each column,
while using the expiration time to break tie will lead
to a more consistent results where a set of cell from
only one of the upserts will be selected.
Fixesscylladb/scylladb#14182
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently, it is hard to tell which of the many sub-cases
fail in this unit test, in case any of them fails.
This change uses logging in debug and trace level
to help with that by reproducing the error
with --logger-log-level testlog=trace
(The cases are deterministic so reproducing should not
be a problem)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
After a schema change, memtable and cache have to be upgraded to the new schema. Currently, they are upgraded (on the first access after a schema change) atomically, i.e. all rows of the entry are upgraded with one non-preemptible call. This is a one of the last vestiges of the times when partition were treated atomically, and it is a well known source of numerous large stalls.
This series makes schema upgrades gentle (preemptible). This is done by co-opting the existing MVCC machinery.
Before the series, all partition_versions in the partition_entry chain have the same schema, and an entry upgrade replaces the entire chain with a single squashed and upgraded version.
After the series, each partition_version has its own schema. A partition entry upgrade happens simply by adding an empty version with the new schema to the head of the chain. Row entries are upgraded to the current schema on-the-fly by the cursor during reads, and by the MVCC version merge ongoing in the background after the upgrade.
The series:
1. Does some code cleanup in the mutation_partition area.
2. Adds a schema field to partition_version and removes it from its containers (partition_snapshot, cache_entry, memtable_entry).
3. Adds upgrading variants of constructors and apply() for `row` and its wrappers.
4. Prepares partition_snapshot_row_cursor, mutation_partition_v2::apply_monotonically and partition_snapshot::merge_partition_versions for dealing with heterogeneous version chains.
5. Modifies partition_entry::upgrade to perform upgrades by extending the version chain with a new schema instead of squashing it to a single upgraded version.
Fixes#2577Closes#13761
* github.com:scylladb/scylladb:
test: mvcc_test: add a test for gentle schema upgrades
partition_version: make partition_entry::upgrade() gentle
partition_version: handle multi-schema snapshots in merge_partition_versions
mutation_partition_v2: handle schema upgrades in apply_monotonically()
partition_version: remove the unused "from" argument in partition_entry::upgrade()
row_cache_test: prepare test_eviction_after_schema_change for gentle schema upgrades
partition_version: handle multi-schema entries in partition_entry::squashed
partition_snapshot_row_cursor: handle multi-schema snapshots
partiton_version: prepare partition_snapshot::squashed() for multi-schema snapshots
partition_version: prepare partition_snapshot::static_row() for multi-schema snapshots
partition_version: add a logalloc::region argument to partition_entry::upgrade()
memtable: propagate the region to memtable_entry::upgrade_schema()
mutation_partition: add an upgrading variant of lazy_row::apply()
mutation_partition: add an upgrading variant of rows_entry::rows_entry
mutation_partition: switch an apply() call to apply_monotonically()
mutation_partition: add an upgrading variant of rows_entry::apply_monotonically()
mutation_fragment: add an upgrading variant of clustering_row::apply()
mutation_partition: add an upgrading variant of row::row
partition_version: remove _schema from partition_entry::operator<<
partition_version: remove the schema argument from partition_entry::read()
memtable: remove _schema from memtable_entry
row_cache: remove _schema from cache_entry
partition_version: remove the _schema field from partition_snapshot
partition_version: add a _schema field to partition_version
mutation_partition: change schema_ptr to schema& in mutation_partition::difference
mutation_partition: change schema_ptr to schema& in mutation_partition constructor
mutation_partition_v2: change schema_ptr to schema& in mutation_partition_v2 constructor
mutation_partition: add upgrading variants of row::apply()
partition_version: update the comment to apply_to_incomplete()
mutation_partition_v2: clean up variants of apply()
mutation_partition: remove apply_weak()
mutation_partition_v2: remove a misleading comment in apply_monotonically()
row_cache_test: add schema changes to test_concurrent_reads_and_eviction
mutation_partition: fix mixed-schema apply()
We don't have a convention for when to pass `schema_ptr` and and when to pass
`const schema&` around.
In general, IMHO the natural convention for such a situation is to pass the
shared pointer if the callee might extend the lifetime of shared_ptr,
and pass a reference otherwise. But we convert between them willy-nilly
through shared_from_this().
While passing a reference to a function which actually expects a shared_ptr
can make sense (e.g. due to the fact that smart pointers can't be passed in
registers), the other way around is rather pointless.
This patch takes one occurence of that and modifies the parameter to a reference.
Since enable_shared_from_this makes shared pointer parameters and reference
parameters interchangeable, this is a purely cosmetic change.
Most variants of apply() and apply_monotonically() in mutation_partition_v2
are leftovers from mutation_partition, and are unused. Thus they only
add confusion and maintenance burden. Since we will be modifying
apply_monotonically() in upcoming patches, let's clean them up, lest
the variants become stale.
This patch removes all unused variants of apply() and apply_monotonically()
and "manually inlines" the variants which aren't used often enough to carry
their own weight.
In the end, we are left with a single apply_monotonically() and two convenience
apply() helpers.
The single apply_monotonically() accepts two schema arguments. This facility
is unimplemented and unused as of this patch - the two arguments are always
the same - but it will be implemented and used in later parts of the series.
This PR introduces an experimental feature called "tablets". Tablets are
a way to distribute data in the cluster, which is an alternative to the
current vnode-based replication. Vnode-based replication strategy tries
to evenly distribute the global token space shared by all tables among
nodes and shards. With tablets, the aim is to start from a different
side. Divide resources of replica-shard into tablets, with a goal of
having a fixed target tablet size, and then assign those tablets to
serve fragments of tables (also called tablets). This will allow us to
balance the load in a more flexible manner, by moving individual tablets
around. Also, unlike with vnode ranges, tablet replicas live on a
particular shard on a given node, which will allow us to bind raft
groups to tablets. Those goals are not yet achieved with this PR, but it
lays the ground for this.
Things achieved in this PR:
- You can start a cluster and create a keyspace whose tables will use
tablet-based replication. This is done by setting `initial_tablets`
option:
```
CREATE KEYSPACE test WITH replication = {'class': 'NetworkTopologyStrategy',
'replication_factor': 3,
'initial_tablets': 8};
```
All tables created in such a keyspace will be tablet-based.
Tablet-based replication is a trait, not a separate replication
strategy. Tablets don't change the spirit of replication strategy, it
just alters the way in which data ownership is managed. In theory, we
could use it for other strategies as well like
EverywhereReplicationStrategy. Currently, only NetworkTopologyStrategy
is augmented to support tablets.
- You can create and drop tablet-based tables (no DDL language changes)
- DML / DQL work with tablet-based tables
Replicas for tablet-based tables are chosen from tablet metadata
instead of token metadata
Things which are not yet implemented:
- handling of views, indexes, CDC created on tablet-based tables
- sharding is done using the old method, it ignores the shard allocated in tablet metadata
- node operations (topology changes, repair, rebuild) are not handling tablet-based tables
- not integrated with compaction groups
- tablet allocator piggy-backs on tokens to choose replicas.
Eventually we want to allocate based on current load, not statically
Closes#13387
* github.com:scylladb/scylladb:
test: topology: Introduce test_tablets.py
raft: Introduce 'raft_server_force_snapshot' error injection
locator: network_topology_strategy: Support tablet replication
service: Introduce tablet_allocator
locator: Introduce tablet_aware_replication_strategy
locator: Extract maybe_remove_node_being_replaced()
dht: token_metadata: Introduce get_my_id()
migration_manager: Send tablet metadata as part of schema pull
storage_service: Load tablet metadata when reloading topology state
storage_service: Load tablet metadata on boot and from group0 changes
db, migration_manager: Notify about tablet metadata changes via migration_listener::on_update_tablet_metadata()
migration_notifier: Introduce before_drop_keyspace()
migration_manager: Make prepare_keyspace_drop_announcement() return a future<>
test: perf: Introduce perf-tablets
test: Introduce tablets_test
test: lib: Do not override table id in create_table()
utils, tablets: Introduce external_memory_usage()
db: tablets: Add printers
db: tablets: Add persistence layer
dht: Use last_token_of_compaction_group() in split_token_range_msb()
locator: Introduce tablet_metadata
dht: Introduce first_token()
dht: Introduce next_token()
storage_proxy: Improve trace-level logging
locator: token_metadata: Fix confusing comment on ring_range()
dht, storage_proxy: Abstract token space splitting
Revert "query_ranges_to_vnodes_generator: fix for exclusive boundaries"
db: Exclude keyspace with per-table replication in get_non_local_strategy_keyspaces_erms()
db: Introduce get_non_local_vnode_based_strategy_keyspaces()
service: storage_proxy: Avoid copying keyspace name in write handler
locator: Introduce per-table replication strategy
treewide: Use replication_strategy_ptr as a shorter name for abstract_replication_strategy::ptr_type
locator: Introduce effective_replication_map
locator: Rename effective_replication_map to vnode_effective_replication_map
locator: effective_replication_map: Abstract get_pending_endpoints()
db: Propagate feature_service to abstract_replication_strategy::validate_options()
db: config: Introduce experimental "TABLETS" feature
db: Log replication strategy for debugging purposes
db: Log full exception on error in do_parse_schema_tables()
db: keyspace: Remove non-const replication strategy getter
config: Reformat
this change ensures that `dk._key` is formatted with the "pk" prefix.
as in 3738fcb, the `operator<<` for partition_key was removed. so the
compiler has to find an alternative when trying to fulfill the needs
when this operator<< is called. fortunately, from the compiler's
perspective, `partition_key` has an `operator managed_bytes_view`, and
this operator does not have the explicit specifier, and,
`managed_bytes_view` does support `operator<<`. so this ends up with a
change in the format of `decorated_key` when it is printed using
`operator<<`. the code compiles. but unfortunately, the behavior is
changed, and it breaks scylla-dtest/cdc_tracing_info_test.py where the
partition_key is supposed to be printed like "pk{010203}" instead of
"010203". the latter is how `managed_bytes_view` is formatted.
a test is added accordingly to avoid future changes which break the
dtest.
Fixes scylladb#13628
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13653
Will be used by tablet-based replication strategies, for which
effective replication map is different per table.
Also, this patch adapts existing users of effective replication map to
use the per-table effective replication map.
For simplicity, every table has an effective replication map, even if
the erm is per keyspace. This way the client code can be uniform and
doesn't have to check whether replication strategy is per table.
Not all users of per-keyspace get_effective_replication_map() are
adapted yet to work per-table. Those algorithms will throw an
exception when invoked on a keyspace which uses per-table replication
strategy.
The purpose of `_stop` is to remember whether the consumption of the
last partition was interrupted or it was consumed fully. In the former
case, the compactor allows retreiving the compaction state for the given
partition, so that its compaction can be resumed at a later point in
time.
Currently, `_stop` is set to `stop_iteration::yes` whenever the return
value of any of the `consume()` methods is also `stop_iteration::yes`.
Meaning, if the consuming of the partition is interrupted, this is
remembered in `_stop`.
However, a partition whose consumption was interrupted is not always
continued later. Sometimes consumption of a partitions is interrputed
because the partition is not interesting and the downstream consumer
wants to stop it. In these cases the compactor should not return an
engagned optional from `detach_state()`, because there is not state to
detach, the state should be thrown away. This was incorrectly handled so
far and is fixed in this patch, but overwriting `_stop` in
`consume_partition_end()` with whatever the downstream consumer returns.
Meaning if they want to skip the partition, then `_stop` is reset to
`stop_partition::no` and `detach_state()` will return a disengaged
optional as it should in this case.
Fixes: #12629Closes#13365
Tables need to know which storage their sstables need to be located at,
so class table needs to have itw reference of the storage options. The
thing can be inherited from the keyspace metadata.
Tests sometimes create table without keyspace at hand. For those use
default-initialized storage options (which is local storage).
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
these warnings are found by Clang-17 after removing
`-Wno-unused-lambda-capture` and '-Wno-unused-variable' from
the list of disabled warnings in `configure.py`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
In test_v2_apply_monotonically_is_monotonic_on_alloc_failures we
generate mutations with non-full continuity, so we should pass
is_evictable::yes to apply_monotonically(). Otherwise, it will assume
fully-continuous versions and not try to maintain continuity by
inserting sentinels.
This manifested in sporadic failures on continuity check.
Fixes#12882Closes#12921
* github.com:scylladb/scylladb:
test: mutation_test: Fix sporadic failure due to continuity mismatch
test: mutation_test: Fix copy-paste mistake in trace-level logging
In test_v2_apply_monotonically_is_monotonic_on_alloc_failures we
generate mutations with non-full continuity, so we should pass
is_evictable::yes to apply_monotonically(). Otherwise, it will assume
fully-continuous versions and not try to maintain continuity by
inserting sentinels.
This manifested in sporadic failures on continuity check.
Fixes#12882
Schema related files are moved there. This excludes schema files that
also interact with mutations, because the mutation module depends on
the schema. Those files will have to go into a separate module.
Closes#12858
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
Introduces task manager's compaction module. That's an initial
part of integration of compaction with task manager.
When fully integrated, task manager will allow user to track compaction
operations, check status and progress of each individual one. It will help
with creating an asynchronous version of rest api that forces any compaction.
Currently, users can see with /task_manager/list_modules api call that
compaction is one of the modules accessible through task manager.
They won't get any additional information though, since compaction
tasks are not created yet.
A shared_ptr to compaction module is kept in compaction manager.
Closes#12635
* github.com:scylladb/scylladb:
compaction: test: pass task_manager to compaction_manager in test environment
compaction: create and register task manager's module for compaction
tasks: add task_manager constructor without arguments
This series switches memtable and cache to use a new representation for mutation data,
called `mutation_partition_v2`. In this representation, range tombstone information is stored
in the same tree as rows, attached to row entries. Each entry has a new tombstone field,
which represents range tombstone part which applies to the interval between this entry and
the previous one. See docs/dev/mvcc.md for more details about the format.
The transient mutation object still uses the old model in order to avoid work needed to adapt
old code to the new model. It may also be a good idea to live with two models, since the
transient mutation has different requirements and thus different trade-offs can be made.
Transient mutation doesn't need to support eviction and strong exception guarantees,
so its algorithms and in-memory representation can be simpler.
This allows us to incrementally evict range tombstone information. Before this series,
range tombstones were accumulated and evicted only when the whole partition entry was evicted. This
could lead to inefficient use of cache memory.
Another advantage of the new representation is that reads don't have to lookup
range tombstone information in a different tree while reading. This leads to simpler
and more efficient readers.
There are several disadvantages too. Firstly, rows_entry is now larger by 16 bytes.
Secondly, update algorithms are more complex because they need to deoverlap range tombstone
information. Also, to handle preemption and provide strong exception guarantees, update
algorithms may need to allocate sentinel entries, which adds complexity and reduces performance.
The memtable reader was changed to use the same cursor implementation
which cache uses, for improved code reuse and reducing risk of bugs
due to discrepancy of algorithms which deal with MVCC.
Remaining work:
- performance optimizations to apply_monotonically() to avoid regressions
- performance testing
- preemption support in apply_to_incomplete (cache update from memtable)
Fixes#2578Fixes#3288Fixes#10587Closes#12048
* github.com:scylladb/scylladb:
test: mvcc: Extend some scenarios with exhaustive consistency checks on eviction
test: mvcc: Extract mvcc_container::allocate_in_region()
row_cache, lru: Introduce evict_shallow()
test: mvcc: Avoid copies of mutation under failure injection
test: mvcc: Add missing logalloc::reclaim_lock to test_apply_is_atomic
mutation_partition_v2: Avoid full scan when applying mutation to non-evictable
Pass is_evictable to apply()
tests: mutation_partition_v2: Introduce test_external_memory_usage_v2 mirroring the test for v1
tests: mutation: Fix test_external_memory_usage() to not measure mutation object footprint
tests: mutation_partition_v2: Add test for exception safety of mutation merging
tests: Add tests for the mutation_partition_v2 model
mutation_partition_v2: Implement compact()
cache_tracker: Extract insert(mutation_partition_v2&)
mvcc, mutation_partition: Document guarantees in case merging succeeds
mutation_partition_v2: Accept arbitrary preemption source in apply_monotonically()
mutation_partition_v2: Simplify get_continuity()
row_cache: Distinguish dummy insertion site in trace log
db: Use mutation_partition_v2 in mvcc
range_tombstone_change_merger: Introduce peek()
readers: Extract range_tombstone_change_merger
mvcc: partition_snapshot_row_cursor: Handle non-evictable snapshots
mvcc: partition_snapshot_row_cursor: Support digest calculation
mutation_partition_v2: Store range tombstones together with rows
db: Introduce mutation_partition_v2
doc: Introduce docs/dev/mvcc.md
db: cache_tracker: Introduce insert() variant which positions before existing entry in the LRU
db: Print range_tombstone bounds as position_in_partition
test: memtable_test: Relax test_segment_migration_during_flush
test: cache_flat_mutation_reader: Avoid timestamp clash
test: cache_flat_mutation_reader_test: Use monotonic timestamps when inserting rows
test: mvcc: Fix sporadic failures due to compact_for_compaction()
test: lib: random_mutation_generator: Produce partition tombstone less often
test: lib: random_utils: Introduce with_probability()
test: lib: Improve error message in has_same_continuity()
test: mvcc: mvcc_container: Avoid UB in tracker() getter when there is no tracker
test: mvcc: Insert entries in the tracker
test: mvcc_test: Do not set dummy::no on non-clustering rows
mutation_partition: Print full position in error report in append_clustered_row()
db: mutation_cleaner: Extract make_region_space_guard()
position_in_partition: Optimize equality check
mvcc: Fix version merging state resetting
mutation_partition: apply_resume: Mark operator bool() as explicit
