When purging regular tombstone consult the min_live_timestamp, if available.
This is safe since we don't need to protect dead data from resurrection, as it is already dead.
For shadowable_tombstones, consult the min_memtable_live_row_marker_timestamp,
if available, otherwise fallback to the min_live_timestamp.
If we see in a view table a shadowable tombstone with time T, then in any row where the row marker's timestamp is higher than T the shadowable tombstone is completely ignored and it doesn't hide any data in any column, so the shadowable tombstone can be safely purged without any effect or risk resurrecting any deleted data.
In other words, rows which might cause problems for purging a shadowable tombstone with time T are rows with row markers older or equal T. So to know if a whole sstable can cause problems for shadowable tombstone of time T, we need to check if the sstable's oldest row marker (and not oldest column) is older or equal T. And the same check applies similarly to the memtable.
If both extended timestamp statistics are missing, fallback to the legacy (and inaccurate) min_timestamp.
Fixesscylladb/scylladb#20423Fixesscylladb/scylladb#20424
> [!NOTE]
> no backport needed at this time
> We may consider backport later on after given some soak time in master/enterprise
> since we do see tombstone accumulation in the field under some materialized views workloads
Closesscylladb/scylladb#20446
* github.com:scylladb/scylladb:
cql-pytest: add test_compaction_tombstone_gc
sstable_compaction_test: add mv_tombstone_purge_test
sstable_compaction_test: tombstone_purge_test: test that old deleted data do not inhibit tombstone garbage collection
sstable_compaction_test: tombstone_purge_test: add testlog debugging
sstable_compaction_test: tombstone_purge_test: make_expiring: use next_timestamp
sstable, compaction: add debug logging for extended min timestamp stats
compaction: get_max_purgeable_timestamp: use memtable and sstable extended timestamp stats
compaction: define max_purgeable_fn
tombstone: can_gc_fn: move declaration to compaction_garbage_collector.hh
sstables: scylla_metadata: add ext_timestamp_stats
compaction_group, storage_group, table_state: add extended timestamp stats getters
sstables, memtable: track live timestamps
memtable_encoding_stats_collector: update row_marker: do nothing if missing
Uncompressed SSTables store their checksums in a separate CRC.db file.
Add this in the list of SSTable components.
Since this component is used only for validation, load the component
on-demand for validation tasks and delete it when all validation tasks
finish. In more detail:
- Make the checksum component shareable and weakly referencable.
Also, add a constructor since it is no longer an aggregate.
- Use a weak pointer to store a non-owning reference in the components
and a shared pointer to keep the object alive while validation runs.
Once validation finishes, the component should be cleaned up
automatically.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
Store and retrieve the optional extended timestamp statistics
(min_live_timestamp and min_live_row_marker_timestamp)
in the scylla_metadata component.
Note that there is no need for a cluster feature to
store those attributes since the scylla_metadata
on-disk format is extensible so that old sstables
can be read by new versions, seeing the extra stats
is missing, and new sstables can be read by old
versions that ignore unknown scylla metadata section types.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
`sstables::write()` has multiple overloads, which are defined in
`sstables/writer.hh`. two of these overloads are template functions,
which have a template parameter named `W`, which has a type constraint
requiring it to fulfill the `Writer` concept. but in `types.hh`, when
the compiler tries to instantiate the template function with signature
of `write(sstable_version_types v, W& out, const T& t)` with
`file_writer` as the template parameter of `w`, `file_writer` is only
forward-declared using `class file_writer` in the same header file, so
this type is still an incomplete type at that moment. that's why the
compiler is not able to determine if `file_writer` fulfills the
constraint or not. actually, the declaration of `file_writer` is located
in `sstables/writer.hh`, which in turn includes `types.hh`. so they
form a cyclic dependency.
in this change, in order to break this cycle, we extract file_writer out
into a separate header file, so that both `sstables/writer.hh` and
`sstables/types.hh` can include it. this address the build failure.
Fixesscylladb/scylladb#19667
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#19669
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::deletion_time`,
drop its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@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 formatters for `sstables::indexable_element`,
drop its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
before we support incremental repair, these is no point have the
code path setting / getting it. and even worse, it incurs confusion.
so, in this change, we
* just set the field to 0,
* drop the corresponding field in metadata_collector, as we never
update it.
* add a comment to explain why this variable is initialized to 0
Fixes#16098
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#16169
in C++20, compiler generate operator!=() if the corresponding
operator==() is already defined, the language now understands
that the comparison is symmetric in the new standard.
fortunately, our operator!=() is always equivalent to
`! operator==()`, this matches the behavior of the default
generated operator!=(). so, in this change, all `operator!=`
are removed.
in addition to the defaulted operator!=, C++20 also brings to us
the defaulted operator==() -- it is able to generated the
operator==() if the member-wise lexicographical comparison.
under some circumstances, this is exactly what we need. so,
in this change, if the operator==() is also implemented as
a lexicographical comparison of all memeber variables of the
class/struct in question, it is implemented using the default
generated one by removing its body and mark the function as
`default`. moreover, if the class happen to have other comparison
operators which are implemented using lexicographical comparison,
the default generated `operator<=>` is used in place of
the defaulted `operator==`.
sometimes, we fail to mark the operator== with the `const`
specifier, in this change, to fulfil the need of C++ standard,
and to be more correct, the `const` specifier is added.
also, to generate the defaulted operator==, the operand should
be `const class_name&`, but it is not always the case, in the
class of `version`, we use `version` as the parameter type, to
fulfill the need of the C++ standard, the parameter type is
changed to `const version&` instead. this does not change
the semantic of the comparison operator. and is a more idiomatic
way to pass non-trivial struct as function parameters.
please note, because in C++20, both operator= and operator<=> are
symmetric, some of the operators in `multiprecision` are removed.
they are the symmetric form of the another variant. if they were
not removed, compiler would, for instance, find ambiguous
overloaded operator '=='.
this change is a cleanup to modernize the code base with C++20
features.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13687
Scylla stores a dht::token into each summary entry, for convenience.
But that costs us 16 bytes for each summary entry. That's because
dht::token has a kind field in addition to data, both 64 bits.
With 1kk partitions, each averaging 4k bytes, summary may end up
with ~90k summary entries. So dht::token only will add ~1.5M to the
memory footprint of summary.
We know summary samples index keys, therefore all tokens in all
summary entries cannot have any token kind other than 'key'.
Therefore, we can save 8 bytes for each summary entry by storing
a 64-bit raw token and converting it back into token whenever
needed.
Memory footprint of summary entries in a summary goes from
sizeof(summary_entry) * entries.size(): 1771520
to
sizeof(summary_entry) * entries.size(): 1417216
which is explained by the 8 bytes reduction per summary entry.
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
Add a new large_data_stats type and entry for keeping
the collection_elements_count_threshold and the maximum value
of collection_elements.
Signed-off-by: Benny Halevy <bhalevy@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
There are three variants: integral, enum, and self-describing
(currently expressed as not integral and not enum). Convert to
concepts by using the standard concepts or the new self_describing
concept.
Our sstable parsing and writing code contains a self-describing
type concept, where a type can advertise its members via a
describe_types() member function with a specific protocol.
Formalize that into a C++ concept. This is a little tricky, since
describe_type() accepts a parameter that is itself a template, and
requires clauses only work with concrete type. To handle this problem,
create such a concrete example type and use it in the concept.
Add new scylla_metadata_type::SSTableOrigin.
Store and retrive a sstring to the scylla metadata component.
Pass sstable_writer_config::origin from the mx sstable writer
and ignore it in the k_l writer.
Add unit test to verify the sstable_origin extension
using both empty and a random string.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Store the large data statistics in the scylla_metadata component.
These will be retrieved when loading the sstable and be
used for determining whether to delete the corresponding
large data entries upon sstable deletion.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add the sstable_version_types::md enum value
and logically extend sstable_version_types comparisons to cover
also the > sstable_version_types::mc cases.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
It is used only for updating the metadata_collector {min,max}_column_names.
Implement metadata_collector::do_update_min_max_components in
sstables/metadata_collector.cc that will be used to host some other
metadata_collector methods in following patches that need not be
implemented in the header file.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Seastar recently lost support for the experimental Concepts Technical
Specification (TS) and gained support for C++20 concepts. Re-enable
concepts in Scylla by updating our use of concepts to the C++20
standard.
This change:
- peels off uses of the GCC6_CONCEPT macro
- removes inclusions of <seastar/gcc6-concepts.hh>
- replaces function-style concepts (no longer supported) with
equation-style concepts
- semicolons added and removed as needed
- deprecated std::is_pod replaced by recommended replacement
- updates return type constraints to use concepts instead of
type names (either std::same_as or std::convertible_to, with
std::same_as chosen when possible)
No attempt is made to improve the concepts; this is a specification
update only.
Message-Id: <20200531110254.2555854-1-avi@scylladb.com>
Some legacy `mc` SSTables (created in Scylla 3.0) may contain incorrect
serialization headers, which don't wrap frozen UDTs nested inside collections
with the FrozenType<...> tag. When reading such SSTable,
Scylla would detect a mismatch between the schema saved in schema
tables (which correctly wraps UDTs in the FrozenType<...> tag) and the schema
from the serialization header (which doesn't have these tags).
SSTables created in Scylla versions 3.1 and above, in particular in
Scylla versions that contain this commit, create correct serialization
headers (which wrap UDTs in the FrozenType<...> tag).
This commit does two things:
1. for all SSTables created after this commit, include a new feature
flag, CorrectUDTsInCollections, presence of which implies that frozen
UDTs inside collections have the FrozenType<...> tag.
2. when reading a Scylla SSTable without the feature flag, we assume that UDTs
nested inside collections are always frozen, even if they don't have
the tag. This assumption is safe to be made, because at the time of
this commit, Scylla does not allow non-frozen (multi-cell) types inside
collections or UDTs, and because of point 1 above.
There is one edge case not covered: if we don't know whether the SSTable
comes from Scylla or from C*. In that case we won't make the assumption
described in 2. Therefore, if we get a mismatch between schema and
serialization headers of a table which we couldn't confirm to come from
Scylla, we will still reject the table. If any user encounters such an
issue (unlikely), we will have to use another solution, e.g. using a
separate tool to rewrite the SSTable.
Fixes#6130.
It is save to do such change because we support only
Murmur3Partitioner which uses only tokens that are
8 bytes long.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
gcc 10 requires a semicolon after every compound requirement,
as per the standard. Add missing semicolons where necessary.
Message-Id: <20200129205805.20928-1-avi@scylladb.com>
Static compact tables are tables with compact storage and no
clustering columns.
Before this patch, Scylla was writing rows of static compact tables as
clustered rows instead of static rows. That's because in our in-memory
model such tables have regular rows and no static row. In Cassandra's
schema (since 3.x), those tables have columns which are marked as
static and there are no regular columns.
This worked fine as long as Scylla was writing and reading those
sstables. But when importing sstables from Cassandra, our reader was
skipping the static row, since it's not present in the schema, and
returning no rows as a result. Also, Cassandra, and Scylla tools,
would have problems reading those sstables.
Fix this by writing rows for such tables the same way as Cassandra
does. In order to support rolling downgrade, we do that only when all
nodes are upgraded.
Fixes#4139.
max local_deletion_time_tracker in stats is int32_t so just track the limit
of (max int32_t - 1) if time_point is greater than the limit.
This corresponds to Cassandra's MAX_DELETION_TIME.
Refs #3353
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
mc format only writes delta local_deletion_time of tombstones.
Conventional deletion_time is written only for the partition header.
Restructure the code to pass a tombstone to write_delta_deletion_time
rather than struct deletion_time to prepare for using 64-bit deletion times.
The tombstone uses gc_clock::time_point while struct
deletion_time is limited to int32_t local_deletion_time.
Note that for "live" tombstones we encode <api::missing_timestamp,
no_deletion_time> as was previously evaluated by to_deletion_time().
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Fix runtime error: signed integer overflow
introduced by 2dc3776407
Delta-encoded values may wrap around if the encoded value is
less than the base value. This could happen in two places:
In the mc-format serialization header itself, where the base values are implicit
Cassandra epoch time, and in the sstables data files, where the base values
are taken from the encoding_stats (later written to the serialization_header).
In these cases, when the calculation is done using signed integer/long we may see
"runtime error: signed integer overflow" messages in debug mode
(with -fsanitize=undefined / -fsanitize=signed-integer-overflow).
Overflow here is expected and harmless since we do not gurantee that
neither the base values in the serialization header are greater than
or equal to Cassandra's epoch now that the delta-encoded values are
always greater than or equal to the respective base values in
the serialization header.
To prevent these warnings, the subtraction/addition should be done with unsigned
(two's complement) arithmetic and the result converted to the signed type.
Note that to keep the code simple where possible, when also rely on implicit
conversion of signed integers to unsigned when either one of added value is unsigned
and the other is signed.
Fixes: #4098
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20190120142950.15776-1-bhalevy@scylladb.com>
This renames some variables and functions to make it clear that they
refer to partitions and not rows.
Old versions of sstablemetadata used to refer to a row histogram, but
current versions now mention a partition histogram instead.
This patch doesn't change the exposed API names.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Message-Id: <20181229223311.4184-2-espindola@scylladb.com>
Replace stdx::optional and stdx::string_view with the C++ std
counterparts.
Some instances of boost::variant were also replaced with std::variant,
namely those that called seastar::visit.
Scylla now requires GCC 8 to compile.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
Message-Id: <20190108111141.5369-1-duarte@scylladb.com>
Before this patch we were writing offset map enteies in unspecified
order, the one returned by std::unorderd_map. Cassandra writes them
sorted by metadata_type. Use the same order for improved
compatibility.
Fixes#3955.
Message-Id: <1543846649-22861-1-git-send-email-tgrabiec@scylladb.com>
Older sstables must have an identifier for them to be associated
with their own run.
Reviewed-by: Nadav Har'El <nyh@scylladb.com>
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
