The central idea of incremental repair is to allow repair participants
to select and repair only a portion of the dataset to speed up the
repair process. All repair participants must utilize an identical
selection method to repair and synchronize the same selected dataset.
There are two primary selection methods: time-based and file-based. The
time-based method selects data within a specified time frame. It is
versatile but it is less efficient because it requires reading all of
the dataset and omitting data beyond the time frame. The file-based
method selects data from unrepaired SSTables and is more efficient
because it allows the entire SSTable to be omitted. This document patch
implements the file-based selection method.
Incremental repair will only be supported for tablet tables; it will not
be supported for vnode tables. On one hand, the legacy vnode is less
important to support. On the other hand, the incremental repair for
vnode is much harder to implement. With vnodes, a SSTalbe could contain
data for multiple vnode ranges. When a given vnode range is repaired,
only a portion of the SSTable is repaired. This complicates the
manipulation of SSTables significantly during both repair and
compaction. With tablets, an entire tablet is repaired so that a
sstable is either fully repaired or not repaired which is a huge
simplification.
This patch uses the repaired_at from sstables::statistics component to
mark a sstable as repaired. It uses a virtual clock as the repair
timestamp, i.e., using a monotonically increasing number for the
repaired_at field of a SSTable and sstables_repaired_at column in
system.tablets table. Notice that when a sstable is not repaired, the
repaired_at field will be set to the default value 0 by default. The
being_repaired in memory field of a SSTable is used to explicitly mark
that a SSTable is being selected. The following variables are used for
incremental repair:
The repaired_at on disk field of a SSTable is used.
- A 64-bit number increases sequentially
The sstables_repaired_at is added to the system.tablets table.
- repaired_at <= sstables_repaired_at means the sstable is repaired
The being_repaired in memory field of a SSTable is added.
- A repair UUID tells which sstable has participated in the repair
Initial test results:
1) Medium dataset results
Node amount: 3
Instance type: i4i.2xlarge
Disk usage per node: ~500GB
Cluster pre-populated with ~500GB of data before starting repairs job.
Results for Repair Timings:
The regular repair run took 210 mins.
Incremental repair 1st run took 183 mins, 2nd and 3rd runs took around 48s
The speedup is: 183 mins / 48s = 228X
2) Small dataset results
Node amount: 3
Instance type: i4i.2xlarge
Disk usage per node: ~167GB
Cluster pre-populated with ~167GB of data before starting the repairs job.
Regular repair 1st run took 110s, 2nd and 3rd runs took 110s.
Incremental repair 1st run took 110 seconds, 2nd and 3rd run took 1.5 seconds.
The speedup is: 110s / 1.5s = 73X
3) Large dataset results
Node amount: 6
Instance type: i4i.2xlarge, 3 racks
50% of base load, 50% read/write
Dataset == Sum of data on each node
Dataset Non-incremental repair (minutes)
1.3 TiB 31:07
3.5 TiB 25:10
5.0 TiB 19:03
6.3 TiB 31:42
Dataset Incremental repair (minutes)
1.3 TiB 24:32
3.0 TiB 13:06
4.0 TiB 5:23
4.8 TiB 7:14
5.6 TiB 3:58
6.3 TiB 7:33
7.0 TiB 6:55
Fixes#22472Closesscylladb/scylladb#24291
* github.com:scylladb/scylladb:
replica: Introduce get_compaction_reenablers_and_lock_holders_for_repair
compaction: Move compaction_reenabler to compaction_reenabler.hh
topology_coordinator: Make rpc::remote_verb_error to warning level
repair: Add metrics for sstable bytes read and skipped from sstables
test.py: Disable incremental for test_tombstone_gc_for_streaming_and_repair
test.py: Add tests for tablet incremental repair
repair: Add tablet incremental repair support
compaction: Add tablet incremental repair support
feature_service: Add TABLET_INCREMENTAL_REPAIR feature
tablet_allocator: Add tablet_force_tablet_count_increase and decrease
repair: Add incremental helpers
sstable: Add being_repaired to sstable
sstables: Add set_repaired_at to metadata_collector
mutation_compactor: Introduce add operator to compaction_stats
tablet: Add sstables_repaired_at to system.tablets table
test: Fix drain api in task_manager_client.py
We are used to symbols definition being grouped in one .cc file, but a
symbol declaration and definition living in separate modules
(subfolders) is surprising.
Relocate always_gc, never_gc, can_always_purge and can_never_purge to
compaction/compaction.cc, from mutatiobn/mutation_partition.cc. The
declarations of these symbols is in
compaction/compaction_garbage_collector.hh.
As requested in #22102, #22103 and #22105 moved the files and fixed other includes and build system.
Moved files:
- clustering_bounds_comparator.hh
- keys.cc
- keys.hh
- clustering_interval_set.hh
- clustering_key_filter.hh
- clustering_ranges_walker.hh
- compound_compat.hh
- compound.hh
- full_position.hh
Fixes: #22102Fixes: #22103Fixes: #22105Closesscylladb/scylladb#25082
C++20 introduced two new attributes--likely and unlikely--that
function as a built-in replacement for __builtin_expect implemented
in various compilers. Since it makes code easier to read and it's
an integral part of the language, there's no reason to not use it
instead.
Closesscylladb/scylladb#24786
Although valid for compact tables, non-full (or empty) clustering key prefixes are not handled for row keys when writing sstables. Only the present components are written, consequently if the key is empty, it is omitted entirely.
When parsing sstables, the parsing code unconditionally parses a full prefix.
This mis-match results in parsing failures, as the parser parses part of the row content as a key resulting in a garbage key and subsequent mis-parsing of the row content and maybe even subsequent partitions.
Introduce a new system table: `system.corrupt_data` and infrastructure similar to `large_data_handler`: `corrupt_data_handler` which abstracts how corrupt data is handled. The sstable writer now passes rows such corrupt keys to the corrupt data handler. This way, we avoid corrupting the sstables beyond parsing and the rows are also kept around in system.corrupt_data for later inspection and possible recovery.
Add a full-stack test which checks that rows with bad keys are correctly handled.
Fixes: https://github.com/scylladb/scylladb/issues/24489
The bug is present in all versions, has to be backported to all supported versions.
Closesscylladb/scylladb#24492
* github.com:scylladb/scylladb:
test/boost/sstable_datafile_test: add test for corrupt data
sstables/mx/writer: handler rows with empty keys
test/lib/cql_assertions: introduce columns_assertions
sstables: add corrupt_data_handler to sstables::sstables
tools/scylla-sstable: make large_data_handler a local
db: introduce corrupt_data_handler
mutation: introduce frozen_mutation_fragment_v2
mutation/mutation_partition_view: read_{clustering,static}_row(): return row type
mutation/mutation_partition_view: extract de-ser of {clustering,static} row
idl-compiler.py: generate skip() definition for enums serializers
idl: extract full_position.idl from position_in_partition.idl
db/system_keyspace: add apply_mutation()
db/system_keyspace: introduce the corrupt_data table
Mirrors frozen_mutation_fragment and shares most of the underlying
serialization code, the only exception is replacing range_tombstone with
range_tombstone_change in the mutation fragment variant.
Instead of mutation_fragment, let caller convert into mutation_fragment.
Allows reuse in future callers which will want to convert to
mutation_fragment_v2.
From the visitor in frozen_mutation_fragment::unfreeze(). We will want
to re-use it in the future frozen_mutation_fragment_v2::unfreeze().
Code-movement only, the code is not changed.
Make sure the keys are full prefixes as it is expected to be the case
for rows. At severeal occasions we have seen empty row keys make their
ways into the sstables, despite the fact that they are not allowed by
the CQL frontend. This means that such empty keys are possibly results
of memory corruption or use-after-{free,copy} errors. The source of the
corruption is impossible to pinpoint when the empty key is discovered in
the sstable. So this patch adds checks for such keys to places where
mutations are built: when building or unserializing mutations.
The test row_cache_test/test_reading_of_nonfull_keys needs adjustment to
work with the changes: it has to make the schema use compact storage,
otherwise the non-full changes used by this tests are rejected by the
new checks.
Fixes: https://github.com/scylladb/scylladb/issues/24506
Move mutation_fragment_v2::kind field into mutation_fragment_v2::data.
Move mutation_fragment::kind field into mutation_fragment::data.
In both cases the move reduces size of the object by half (to 8 bytes).
On top of testsuite this patch was tested manually. First patched scylla was run. A keyspace and a table was created, with columns TEXT, INT, DOUBLE, BOOLEAN and TIMESTAMP. One row was inserted, `select *` was executed to make sure it's there. Then scylla was terminated and non-patched scylla was run, another row was inserted and `select *` was run to verify both rows exist. After this patched scylla was against started, third row was inserted and final `select *` was done to verify all three rows are there.
This is partial fix to https://github.com/scylladb/scylla-enterprise/issues/5288 issue.
Closesscylladb/scylladb#23452
* github.com:scylladb/scylladb:
Move mutation_fragment::kind into data object
Make mutation_fragment::kind enum 1 byte size
Move mutation_fragment_v2::kind into data object
Make mutation_fragment_v2::kind enum 1 byte size
Max purgeable has two possible values for each partition: one for
regular tombstones and one for shadowable ones. Yet currently a single
member is used to cache the max-purgeable value for the partition, so
whichever kind of tombstone is checked first, its max-purgeable will
become sticky and apply to the other kind of tombstones too. E.g. if the
first can_gc() check is for a regular tombstone, its max-purgeable will
apply to shadowable tombstones in the partition too, meaning they might
not be purged, even though they are purgeable, as the shadowable
max-purgeable is expected to be more lenient. The other way around is
worse, as it will result in regular tombstone being incorrectly purged,
permitted by the more lenient shadowable tombstone max-purgeable.
Fix this by caching the two possible values in two separate members.
A reproducer unit test is also added.
Fixes: scylladb/scylladb#23272Closesscylladb/scylladb#24171
Let compact_mutation_state collect all tombstone purge attempts
and failures. For this purpose a new statistic structure is created
(tombstone_purge_stats) and the relative stats are collected in
the can_purge_tombstone method.
The statistics are collect only for sstables compaction.
An optional statistics structure can be passed in via compact_mutation_state
constructor.
Currently, when a max purgeable timestamp is computed, there is no
information where it comes from and how the value was obtained.
Take compaction, if there are memtables or other uncompacting sstables
possibly shadowing data, the timestamp is decreased to ensure a
tombstone is not purged but the caller does not know what that the
timestamp has its value.
In this patch, we extend the return type of max_purgeable_fn to
contain not only a timestamp but also an information on how it was
computed. This information will be required to collect statistics
on tombstone purge failures due to overlapping memtables/uncompacting
sstables that come later in the series.
This adaptor adapts a mutation reader pausable consumer to the frozen
mutation visitor interface. The pausable consumer protocol allows the
consumer to skip the remaining parts of the partition and resume the
consumption with the next one. To do this, the consumer just has to
return stop_iteration::yes from one of the consume() overloads for
clustering elements, then return stop_iteration::no from
consume_end_of_partition(). Due to a bug in the adaptor, this sequence
leads to terminating the consumption completely -- so any remaining
partitions are also skipped.
This protocol implementation bug has user-visible effects, when the
only user of the adaptor -- read repair -- happens during a query which
has limitations on the amount of content in each partition.
There are two such queries: select distinct ... and select ... with
partition limit. When converting the repaired mutation to to query
result, these queries will trigger the skip sequence in the consumer and
due to the above described bug, will skip the remaining partitions in
the results, omitting these from the final query result.
This patch fixes the protocol bug, the return value of the underlying
consumer's consume_end_of_partition() is now respected.
A unit test is also added which reproduces the problem both with select
distinct ... and select ... per partition limit.
Follow-up work:
* frozen_mutation_consumer_adaptor::on_end_of_partition() calls the
underlying consumer's on_end_of_stream(), so when consuming multiple
frozen mutations, the underlying's on_end_of_stream() is called for
each partition. This is incorrect but benign.
* Improve documentation of mutation_reader::consume_pausable().
Fixes: #20084Closesscylladb/scylladb#23657
Currently the dumper unconditionally extracts the value of atomic cells,
assuming they are live. This doesn't always hold of course and
attempting to get the value of a dead cell will lead to marshalling
errors. Fix by checking is_live() before attempting to get the cell
value. Fix for both regular and collection cells.
This doesn't introduce additional work for single-partition queries: the
key is copied anyway on consume_end_of_stream().
Multi-partition reads and compaction are not that sensitive to
additional copy added.
This change fixes a bug in the compacting_reader: currently the reader
passes _last_uncompacted_partition_start.key() to the compactor's
consume_new_partition(). When the compactor emits enough content for this
partition, _last_uncompacted_partition_start is moved from to emit the
partition start, this makes the key reference passed to the compaction
corrupt (refer to moved-from value). This in turn means that subsequent
GC checks done by the compactor will be done with a corrupt key and
therefore can result in tombstone being garbage-collected while they
still cover data elsewhere (data resurrection).
The compacting reader is violating the API contract and normally the bug
should be fixed there. We make an exception here because doing the fix
in the mutation compactor better aligns with our future plans:
* The fix simplifies the compactor (gets rid of _last_dk).
* Prepares the way to get rid of the consume API used by the compactor.
FragmentConsumer[V2] also has no direct users, so fold it into
FlattenedConsumer[V2] as well. With this, FlattenedConsumer[V2] has a
nice and simple definition, with a single nesting level required due to
the return-type flexibility.
Replace boost::accumulate() calls with std::ranges facilities. This
change reduces external dependencies and modernizes the codebase.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#23062
Reorder member variable initialization sequence to ensure `pw` is accessed
before being moved. While the current use-after-move warning from clang-tidy
is a false positive, this change:
- Makes the initialization order more logical
- Eliminates misleading static analysis warnings
- Prevents potential future issues if class structure changes
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22830
In an earlier patch, we introduced regular_column_transformation,
a new type of computed column that does a computation on a cell in
regular column in the base and returns a potentially transformed cell
(value or deletion, timestamp and ttl). In *this* patch, we wire the
materialized view code to support this new kind of computed column that
is usable as a materialized-view key column. This new type of computed
column is not yet used in this patch - this will come in the next
patch, where we will use it for Alternator GSIs.
Before this patch, the logic of deciding when the view update needs
to create a new row or delete a new one, and which timestamp and ttl
to give to the new row, could depend on one (or two - in Alternator)
cells read from base-table regular columns. In this patch, this logic
is rewritten - the notion of "base table regular columns" is generalized
to the notion of "updatable view key columns" - these are view key
columns that an update may change - because they really are base regular
columns, or a computed function of one (regular_column_transformation).
In some sense, the new code is easier to understand - there is no longer
a separate "compute_row_marker()" function, rather the top-level
generate_update() is now in charge of finding the "updatable view key
columns" and calculate the row marker (timestamp and ttl) as part
of deciding what needs to be done.
But unfortunately the code still has separate code paths for "collection
secondary indexing", and also for old-style column_computation (basically,
only token_column_computation). Perhaps in the future this can be further
simplified.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
these unused includes were identifier by clang-include-cleaner. after
auditing these source files, all of the reports have been confirmed.
please note, because quite a few source files relied on
`utils/to_string.hh` to pull in the specialization of
`fmt::formatter<std::optional<T>>`, after removing
`#include <fmt/std.h>` from `utils/to_string.hh`, we have to
include `fmt/std.h` directly.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
now that we are allowed to use C++23. we now have the luxury of using
`std::views::reverse`.
- replace `boost::adaptors::transformed` with `std::views::transform`
- remove unused `#include <boost/range/adaptor/reversed.hpp>`
this change is part of our ongoing effort to modernize our codebase
and reduce external dependencies where possible.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
`prefixed()` is a static function in `mutation_partition_v2.cc`.
and this function is not used in this translation unit. so let's
remove it.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#22006
Replace boost::make_iterator_range() with std::ranges::subrange.
This change improves code modernization and reduces external dependencies:
- Replace boost::make_iterator_range() with std::ranges::subrange
- Remove boost/range/iterator_range.hpp include
- Improve iterator type detection in interval.hh using std::ranges::const_iterator_t<Range>
This is part of ongoing efforts to modernize our codebase and minimize
external dependencies.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21787
since fedora 38 is EOL. and fedora 39 comes with fmt v10.0.0, also,
we've switched to the build image based on fedora 40, which ships
fmt-devel v10.2.1, there is no need to support fmt < 10.
in this change, we drop the support fmt < 10.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21847
Clean up the unnecessary includes reported by the GitHub checks that are
polluting the PR diffs.
The "utils/assert.hh" report should be actually fixed by the #21739, but
as the usage of `SEASTAR_ASSERT()` is protected by the `SEASTAR_DEBUG`
check it makes sense to include the header conditionally as well.
Closesscylladb/scylladb#21817
This commit follows up on commit f436edfa22, which initially cleaned up
unused #include directives in the "mutation" subdirectory. This change
removes additional unused header files that were missed in the previous
cleanup.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21740
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
these unused includes are identified by clang-include-cleaner. after
auditing the source files, all of the reports have been confirmed.
please note, because `mutation/mutation.hh` does not include
`seastar/coroutine/maybe_yield.hh` anymore, and quite a few source
files were relying on this header to bring in the declaration of
`maybe_yield()`, we have to include this header in the places where
this symbol is used. the same applies to `seastar/core/when_all.hh`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
