The `token_metadata_impl` stores the sorted tokens in an `std::vector`.
With a large number of nodes, the size of this vector can grow quickly,
and updating it might lead to oversized allocations.
This commit changes `_sorted_tokens` to a `chunked_vector` to avoid such
issues. It also updates all related code to use `chunked_vector` instead
of `std::vector`.
Fixes#24876
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Closesscylladb/scylladb#25027
these unused includes are identified by clang-include-cleaner.
after auditing the source files, all of the reports have been
confirmed.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
We already have code to return min() for
the minimum and maximum tokens in long_token()
and raw(), so instead of using code to return
it, just make sure to set it in the _data member.
Note that although this change affect serialization,
the existing codebase ignores the deserialized bytes
and places a constant (0 before this patch, or min()
with it) in _data for non-key (minumum or maximum) tokens.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
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>
sizeof(dht::token) is only 16 bytes and therefore
it can be passed with 2 registers.
There is no sense in defining minimum_token
and maximum_token out of line, returning a token&
to statically allocated values that require memory
access/copy, while the only call sites that needs
to point to the static min/max tokens are in
dht::ring_position_view.
Instead, they can be defined inline as constexpr
functions and return their const values.
Respectively, define token ctors and methods
as constexpr where applicable (and noexcept while at it
where applicable)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Make sure to always initalize the _data member
to 0 for non-key (minimum or maximum) tokens.
This allows to simplify the equality operator
that now doesn't need to rely on `operator<=>`
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Token comparisons are abundant.
The equality operator is defined inline
in dht/token.hh by calling `t1 <=> t2`,
and so is `tri_compare_raw`, which `operator<=>`
calls in the common path, but `operator<=>` itself
is defined out of line, losing the benefits of inlining.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
in in {fmt} before v10, it provides the specialization of `fmt::formatter<..>`
for `std::string_view` as well as the specialization of `fmt::formatter<..>`
for `fmt::string_view` which is an implementation builtin in {fmt} for
compatibility of pre-C++17. and this type is used even if the code is
compiled with C++ stadandard greater or equal to C++17. also, before v10,
the `fmt::formatter<std::string_view>::format()` is defined so it accepts
`std::string_view`. after v10, `fmt::formatter<std::string_view>` still
exists, but it is now defined using `format_as()` machinery, so it's
`format()` method does not actually accept `std::string_view`, it
accepts `fmt::string_view`, as the former can be converted to
`fmt::string_view`.
this is why we can inherit from `fmt::formatter<std::string_view>` and
use `formatter<std::string_view>::format(foo, ctx);` to implement the
`format()` method with {fmt} v9, but we cannot do this with {fmt} v10,
and we would have following compilation failure:
```
FAILED: service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o
/home/kefu/.local/bin/clang++ -DFMT_DEPRECATED_OSTREAM -DFMT_SHARED -DSCYLLA_BUILD_MODE=release -DSEASTAR_API_LEVEL=7 -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SSTRING -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"RelWithDebInfo\" -I/home/kefu/dev/scylladb -I/home/kefu/dev/scylladb/build/gen -I/home/kefu/dev/scylladb/seastar/include -I/home/kefu/dev/scylladb/build/seastar/gen/include -I/home/kefu/dev/scylladb/build/seastar/gen/src -ffunction-sections -fdata-sections -O3 -g -gz -std=gnu++20 -fvisibility=hidden -Wall -Werror -Wextra -Wno-error=deprecated-declarations -Wimplicit-fallthrough -Wno-c++11-narrowing -Wno-deprecated-copy -Wno-mismatched-tags -Wno-missing-field-initializers -Wno-overloaded-virtual -Wno-unsupported-friend -Wno-enum-constexpr-conversion -Wno-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb=. -march=westmere -mllvm -inline-threshold=2500 -fno-slp-vectorize -U_FORTIFY_SOURCE -Werror=unused-result -MD -MT service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -MF service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o.d -o service/CMakeFiles/service.dir/RelWithDebInfo/topology_state_machine.cc.o -c /home/kefu/dev/scylladb/service/topology_state_machine.cc
/home/kefu/dev/scylladb/service/topology_state_machine.cc:254:41: error: no matching member function for call to 'format'
254 | return formatter<std::string_view>::format(it->second, ctx);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
/usr/include/fmt/core.h:2759:22: note: candidate function template not viable: no known conversion from 'seastar::basic_sstring<char, unsigned int, 15>' to 'const fmt::basic_string_view<char>' for 1st argument
2759 | FMT_CONSTEXPR auto format(const T& val, FormatContext& ctx) const
| ^ ~~~~~~~~~~~~
```
because the inherited `format()` method actually comes from
`fmt::formatter<fmt::string_view>`. to reduce the confusion, in this
change, we just inherit from `fmt::format<string_view>`, where
`string_view` is actually `fmt::string_view`. this follows
the document at
https://fmt.dev/latest/api.html#formatting-user-defined-types,
and since there is less indirection under the hood -- we do not
use the specialization created by `FMT_FORMAT_AS` which inherit
from `formatter<fmt::string_view>`, hopefully this can improve
the compilation speed a little bit. also, this change addresses
the build failure with {fmt} v10.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18299
Extract decorated_key.hh and ring_position.hh
out of i_partitioner.hh so they can be included
selectively, since i_partitioner.hh contains too much
bagage that is not always needed in full.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move the `token_comparator` definition and
implementation to token.{hh,cc}, respectively
since they are independent of i_partitioner.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently, the coordinator splits the partition range at vnode (or
tablet) boundaries and then tries to merge adjacent ranges which
target the same replica. This is an optimization which makes less
sense with tablets, which are supposed to be of substantial size. If
we don't merge the ranges, then with tablets we can avoid using the
multishard reader on the replica side, since each tablet lives on a
single shard.
The main reason to avoid a multishard reader is avoiding its
complexity, and avoiding adapting it to work with tablet
sharding. Currently, the multishard reader implementation makes
several assumptions about shard assignment which do not hold with
tablets. It assumes that shards are assigned in a round-robin fashion.
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
now that C++20 is able to generate the default-generated comparing
operators for us. there is no need to define them manually. and,
`std::rel_ops::*` are deprecated in C++20.
also, use `foo <=> bar` instead of `tri_compare(foo, bar)` for better
readability.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
this is a part of a series to migrating from `operator<<(ostream&, ..)`
based formatting to fmtlib based formatting. the goal here is to enable
fmtlib to print `dht::token` without the help of `operator<<`.
the corresponding `operator<<()` is preserved in this change, as it
has lots of users in this project, we will tackle them case-by-case in
follow-up changes.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
they are part of the CQL type system, and are "closer" to types.
let's move them into "types" directory.
the building systems are updated accordingly.
the source files referencing `types.hh` were updated using following
command:
```
find . -name "*.{cc,hh}" -exec sed -i 's/\"types.hh\"/\"types\/types.hh\"/' {} +
```
the source files under sstables include "types.hh", which is
indeed the one located under "sstables", so include "sstables/types.hh"
instea, so it's more explicit.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#12926
Add dht::split_token_range_msb that returns a token_range_vector
with ranges split using a given number of most-significant bits.
When creating the table's compaction groups, use dht::split_token_range_msb
to calculate the token_range owned by each compaction_group.
Refs #12594
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add and use dht::compaction_group_of that computes the
compaction_group index by unbiasing the token,
similar to dht::shard_of.
This way, all tokens in `_compaction_groups[i]` are ordered
before `_compaction_groups[j]` iff i < j.
Fixes#12595
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closes#12599
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
This is a set of a few cosmetic changes in dht/token. Mostly some comments and a simplification of `midpoint()`.
Closes#8803
* github.com:scylladb/scylla:
dht: token: add a comment excusing the `const bytes&` constructor
dht: token: simplify midpoint()
dht: token: add a comment to normalize()
dht: token: use {read,write}_unaligned instead of std::copy_n
dht: token-sharding: fix a typo in a comment
Change token's tri_compare functions to return std::strong_ordering,
which is not convertible to bool and therefore not suspect to
being misused where a less-compare is expected.
Two of the users (ring_position and decorated_key) have to undo
the conversion, since they still return int. A follow up will
convert them too.
Ref #1449.
If the key type is int64_t and the less-comparator is "natural" (i.e. it's
literally 'a < b') we may use the SIMD instructions to search for the key
on a node. Before doing so, the maybe_key and the searcher should be prepared
for that, in particular:
1. maybe_key should set unused keys to the minimal value
2. the searcher for this case should call the gt() helper with
primitive types -- int64_t search key and array of int64_t values
To tell to B+ code that the key-less pair is such the less-er should define
the simplify_key() method converting search keys to int64_t-s.
This searcher is selected automatically, if any mismatch happens it silently
falls back to default one. Thus also add a static assertion to the row-cache
to mitigate this.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The <search-key>.token() is noexcept currently and will have
to be explicitly such for future optimized key searcher, so
restrict the constraint and update the related classes.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
In next patches the entries having token on-board will be
moved onto B+-tree rails. For this the int64_t value of the
token will be used as B+ key, so prepare for this.
One corner case -- the after_all_keys tokens must be resolved
to int64::max value to appear at the "end" of the tree. This
is not the same as "before_all_keys" case, which maps to the
int64::min value which is not allowed for regular tokens. But
for the sake of B+ switch this is OK, the conflicts of token
raw values are explicitly resolved in next patches.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
When we switched token representation to int64_t
we added some sanity checks that byte representation
is always 8 bytes long.
It turns out that for token_kind::before_all_keys and
token_kind::after_all_keys bytes can sometimes be empty
because for those tokens they are just ignored. The check
introduced with the change is too strict and sometimes
throws the exception for tokens before/after all keys
created with empty bytes.
This patch relaxes the condition of the check and always
uses 0 as value of _data for special before/after all keys
tokens.
Fixes#6131
Tests: unit(dev, sct)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Previously the tokens were stored as strings
because token could have been represented in multiple ways.
Now token representation is always int64_t so we can
store them as ints in cdc description as well.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Previously _data was stored as array of 8 bytes in
network byte order.
After this change it stores the same value in int64_t
in host byte order.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
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>
