This PR solves a series of similar problems related to executing
methods on an already aborted `raft::server`. They materialize
in various ways:
* For `add_entry` and `modify_config`, a `raft::not_a_leader` with
a null ID will be returned IF forwarding is disabled. This wasn't
a big problem because forwarding has always been enabled for group0,
but it's something that's nice to fix. It's might be relevant for
strong consistency that will heavily rely on this code.
* For `wait_for_leader` and `wait_for_state_change`, the calls may
hang and never resolve. A more detailed scenario is provided in a
commit message.
For the last two methods, we also extend their descriptions to indicate
the new possible exception type, `raft::stopped_error`. This change is
correct since either we enter the functions and throw the exception
immediately (if the server has already been aborted), or it will be
thrown upon the call to `raft::server::abort`.
We fix both issues. A few reproducer tests have been included to verify
that the calls finish and throw the appropriate errors.
Fixes SCYLLADB-841
Backport: Although the hanging problems haven't been spotted so far
(at least to the best of my knowledge), it's best to avoid
running into a problem like that, so let's backport the
changes to all supported versions. They're small enough.
Closesscylladb/scylladb#28822
* https://github.com/scylladb/scylladb:
raft: Make methods throw stopped_error if server aborted
raft: Throw stopped_error if server aborted
test: raft: Introduce get_default_cluster
After the previous changes in `raft::server::{add_entry, modify_config}`
(cf. SCYLLADB-841), we also go through other methods of `raft::server`
and verify that they handle the aborted state properly.
I found two methods that do not:
(A) `wait_for_leader`
(B) `wait_for_state_change`
What happened before these changes?
In case (A), the dangerous scenario occurred when `_leader_promise` was
empty on entering the function. In that case, we would construct the
promise and wait on the corresponding future. However, if the server
had been already aborted before the call, the future would never
resolve and we'd be effectively stuck.
Case (B) is fully analogous: instead of `_leader_promise`, we'd work
with `_stte_change_promise`.
There's probably a more proper solution to this problem, but since I'm
not familiar with the internal code of Raft, I fix it this way. We can
improve it further in the future.
We provide two simple validation tests. They verify that after aborting
a `raft::server`, the calls:
* do not hang (the tests would time out otherwise),
* throw raft::stopped_error.
Fixes SCYLLADB-841
Before the change, calling `add_entry` or `modify_config` on an already
aborted Raft server could result in an error `not_a_leader` containing
a null server ID. It was possible precisely when forwarding was
disabled in the server configuration.
`not_a_leader` is supposed to return the ID of the current leader,
so that was wrong. Furthermore, the description of the function
specified that if a server is aborted, then it should throw
`stopped_error`.
We fix that issue. A few small reproducer tests were provided to verify
that the functions behave correctly with and without forwarding enabled.
Refs SCYLLADB-841
In this series we introduce new system tables and use them for storing the raft metadata
for strongly consistent tables. In contrast to the previously used raft group0 tables, the
new tables can store data on any shard. The tables also allow specifying the shard where
each partition should reside, which enables the tablets of strongly consistent tables to have
their raft group metadata co-located on the same shard as the tablet replica.
The new tables have almost the same schemas as the raft group0 tables. However, they
have an additional column in their partition keys. The additional column is the shard
that specifies where the data should be located. While a tablet and its corresponding
raft group server resides on some shard, it now writes and reads all requests to the
metadata tables using its shard in addition to the group_id.
The extra partition key column is used by the new partitioner and sharder which allow
this special shard routing. The partitioner encodes the shard in the token and the
sharder decodes the shard from the token. This approach for routing avoids any
additional lookups (for the tablet mapping) during operations on the new tables
and it also doesn't require keeping any state. It also doesn't interact negatively
with resharding - as long as tablets (and their corresponding raft metadata) occupy
some shard, we do not allow starting the node with a shard count lower than the
id of this shard. When increasing the shard count, the routing does not change,
similarly to how tablet allocation doesn't change.
To use the new tables, a new implementation of `raft::persistence` is added. Currently,
it's almost an exact copy of the `raft_sys_table_storage` which just uses the new tables,
but in the future we can modify it with changes specific to metadata (or mutation)
storage for strongly consistent tables. The new storage is used in the `groups_manager`,
which combined with the removal of some `this_shard_id() == 0` checks, allows strongly
consistent tables to be used on all shards.
This approach for making sure that the reads/writes to the new tables end up on the correct shards
won in the balance of complexity/usability/performance against a few other approaches we've considered.
They include:
1. Making the Raft server read/write directly to the database, skipping the sharder, on its shard, while using
the default partitioner/sharder. This approach could let us avoid changing the schema and there should be
no problems for reads and writes performed by the Raft server. However, in this approach we would input
data in tables conflicting with the placement determined by the sharder. As a result, any read going through
the sharder could miss the rows it was supposed to read. Even when reading all shards to find a specific value,
there is a risk of polluting the cache - the rows loaded on incorrect shards may persist in the cache for an unknown
amount of time. The cache may also mistakenly remember that a row is missing, even though it's actually present,
just on an incorrect shard.
Some of the issues with this approach could be worked around using another sharder which always returns
this_shard_id() when asked about a shard. It's not clear how such a sharder would implement a method like
`token_for_next_shard`, and how much simpler it would be compared to the current "identity" sharder.
2. Using a sharder depending on the current allocation of tablets on the node. This approach relies on the
knowledge of group_id -> shard mapping at any point in time in the cluster. For this approach we'd also
need to either add a custom partitioner which encodes the group_id in the token, or we'd need to track the
token(group_id) -> shard mapping. This approach has the benefit over the one used in the series of keeping
the partition key as just group_id. However, it requires more logic, and the access to the live state of the node
in the sharder, and it's not static - the same token may be sharded differently depending on the state of the
node - it shouldn't occur in practice, but if we changed the state of the node before adjusting the table data,
we would be unable to access/fix the stale data without artificially also changing the state of the node.
3. Using metadata tables co-located to the strongly consistent tables. This approach could simplify the
metadata migrations in the future, however it would require additional schema management of all co-located
metadata tables, and it's not even obvious what could be used as the partition key in these tables - some
metadata is per-raft-group, so we couldn't reuse the partition key of the strongly consistent table for it. And
finding and remembering a partition key that is routed to a specific shard is not a simple task. Finally, splits
and merges will most likely need special handling for metadata anyway, so we wouldn't even make use of
co-located table's splits and merges.
Fixes [SCYLLADB-361](https://scylladb.atlassian.net/browse/SCYLLADB-361)
[SCYLLADB-361]: https://scylladb.atlassian.net/browse/SCYLLADB-361?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQClosesscylladb/scylladb#28509
* github.com:scylladb/scylladb:
docs: add strong consistency doc
test/cluster: add tests for strongly-consistent tables' metadata persistence
raft: enable multi-shard raft groups for strongly consistent tablets
test/raft: add unit tests for raft_groups_storage
raft: add raft_groups_storage persistence class
db: add system tables for strongly consistent tables' raft groups
dht: add fixed_shard_partitioner and fixed_shard_sharder
raft: add group_id -> shard mapping to raft_group_registry
schema: add with_sharder overload accepting static_sharder reference
We introduce a function creating a Raft cluster with parameters usually
used by the tests. This will avoid code duplication, especially after
introducing new tests in the following commits.
Note that the test `test_aborting_wait_for_state_change` has changed:
the previous complex configuration was unnecessary for it (I wrote it).
Most functions of the new storage for raft groups for strongly
consistent tables are the same as for the system raft table
storage, so we reuse the tests for them to test the new storage.
We add additional tests for checking the new raft groups partitioner
and sharder, and for verifying that writes using storages for different
shards do not affect the data read on different shards.
We also add a test for checking the snapshot_descriptor present after
the storage bootstrap - for both system and strongly consistent storages
we check that the storage contains the initial descriptor.
Replace -1 with 0 for the liveness check operation to avoid triggering
digest validation failures. This prevents rare fatal errors when the
cluster is recovering and ensures the test does not violate append_seq
invariants.
The value -1 was causing invalid digest results in the append_seq
structure, leading to assertion failures. This could happen when the
sentinel value was the first (or only) element being appended, resulting
in a digest that did not match the expected value.
By using 0 instead, we ensure that the digest calculations remain valid
and consistent with the expected behavior of the test.
The specific value of the sentinel is not important, as long as it is
a valid elem_t that does not violate the invariants of the append_seq
structure. In particular, the sentinel value is typically used only
when no valid result is received from any server in the current loop
iteration, in which case the loop will retry.
Fixes: scylladb/scylladb#27307
Move the post-condition check before the assertion to ensure it is
always executed first. Before, the wrong value could be passed to the
digest_remove assertion, making the pre-check trigger there instead of
the post-check as expected.
Also, add a check in the append_seq constructor to ensure that the
digest value is valid when creating an append_seq object.
The Boost ASSERTs in the digest functions of the randomized_nemesis_test
were not working well inside the state machine digest functions, leading
to unhelpful boost::execution_exception errors that terminated the apply
fiber, and didn't provide any helpful information.
Replaced by explicit checks with on_fatal_internal_error calls that
provide more context about the failure. Also added validation of the
digest value after appending or removing an element, which allows to
determine which operation resulted in causing the wrong value.
This effectively reverts the changes done in https://github.com/scylladb/scylladb/pull/19282,
but adds improved error reporting.
Refs: scylladb/scylladb#27307
Refs: scylladb/scylladb#17030Closesscylladb/scylladb#27791
The test had a sporadic failure due to a broken promise exception.
The issue was in `test_pinger::ping()` which captured the promise by
move into the subscription lambda, causing the promise to be destroyed
when the lambda was destroyed during coroutine unwinding.
Simplify `test_pinger::ping()` by replacing manual abort_source/promise
logic with `seastar::sleep_abortable()`.
This removes the risk of promise lifetime/race issues and makes the code
simpler and more robust.
Fixes: scylladb/scylladb#27136
Backport to active branches: This fixes a CI test issue, so it is
beneficial to backport the fix. As this is a test-only fix, it is a low
risk change.
Closesscylladb/scylladb#27737
When direct failure detector was introduces the idea was that it will
run on the same connection raft group0 verbs are running, but in
60f1053087 raft verbs were moved to run on the gossiper connection
while DIRECT_FD_PING was left where it was. This patch move it to
gossiper connection as well and fix the pinger code to run in gossiper
scheduling group.
Currently direct_fd_ping runs without timeout, but the verb is not
waited forever, the wait is canceled after a timeout, this timeout
simply is not passed to the rpc. It may create a situation where the
rpc callback can runs on a destination but it is no longer waited on.
Change the code to pass timeout to rpc as well and return earlier from
the rpc handler if the timeout is reached by the time the callback is
called. This is backwards compatible since timeout is passed as
optional.
This PR refactors the can_vote function in the Raft algorithms for improved clarity and maintainability by providing safer strong boolean types to the raft algorithm.
Fixes: #21937
Backport: No backport required
Closesscylladb/scylladb#25787
Implement repetition of files using pytest_collect_file hook: run
file collection as many times as needed to cover all --mode/--repeat
combinations. Also move disabled test logic to this hook.
Store build mode and run_id in pytest item stashes.
Simplify support of C++ tests: remove redundant facade abstraction and put
all code into 3 files: base.py, boost.py, and unit.py
Add support for `run_first` option in test_config.yaml
`extra_scylla_cmdline_options` is a list of commandline arguments
and, actually, each argument should be a separate item. Few configuration
files have `--reactor-backend` option added in the format which doesn't
follow this rule.
RAFT_TEST_CASE macro creates 2 test cases, one with random 20% packet
loss named name_drops. The framework makes hard coded assumptions about
leader which doesn't hold well in case of packet losses.
This short term fix disables the packet drop variant of the specified test.
It should be safe to re-enable it once the whole framework is re-worked to
remove these hard coded assumptions.
This PR fixes a bug. Hence we need to backport it.
Fixes: scylladb/scylladb#23816Closesscylladb/scylladb#25489
Switch off C++ tests from test.py discovery. With this change, test.py loses
the ability to directly see and run the C++ tests. Instead, it'll delegate all
things to the pytest.
Since boost, raft, unit, and ldap directories aren't executed by test.py,
suite.yaml files are renamed to test_config.yaml
to preserve the old way of test configuration and removing them from execution
by test.py
Before this patch boost test were visible by test.py and pytest. So if the
test.py will be invoked without test name, it will execute boost tests twice:
with test.py executor and with pytest executor. Depending on the test name
according executor will be used. For example, if test name is
test/boost/aggregate_fcts_test.cc it will be executed by pytest, but if the
boost/aggregate_fcts_test it will be executed by test.py executor.
Clang 20 complains when it sees a user-defined literal operator
defined with a space before the underscore. Assume it's adhering
to the standard and comply.
Closesscylladb/scylladb#23401
Since mid December, tests started failing with ENOMEM while
submitting I/O requests.
Logs of failed tests show IO uring was used as backend, but we
never deliberately switched to IO uring. Investigation pointed
to it happening accidentaly in commit 1bac6b75dc,
which turned on IO uring for allowing native tool in production,
and picked linux-aio backend explicitly when initializing Scylla.
But it missed that seastar-based tests would pick the default
backend, which is io_uring once enabled.
There's a reason we never made io_uring the default, which is
that it's not stable enough, and turns out we made the right
choice back then and it apparently continue to be unstable
causing flakiness in the tests.
Let's undo that accidental change in tests by explicitly
picking the linux-aio backend for seastar-based tests.
This should hopefully bring back stability.
Refs #21968.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closesscylladb/scylladb#22695
This series exposes a Clock template parameter for loading_cache so that the test could use
the manual_clock rather than the lowres_clock, since relying on the latter is flaky.
In addition, the test load function is simplified to sleep some small random time and co_return the expected string,
rather than reading it from a real file, since the latter's timing might also be flaky, and it out-of-scope for this test.
Fixes#20322
* The test was flaky forever, so backport is required for all live versions.
Closesscylladb/scylladb#22064
* github.com:scylladb/scylladb:
tests: loading_cache_test: use manual_clock
utils: loading_cache: make clock_type a template parameter
test: loading_cache_test: use function-scope loader
test: loading_cache_test: simlute loader using sleep
test: lib: eventually: add sleep function param
test: lib: eventually: make *EVENTUALLY_EQUAL inline functions
rather then macros.
This is a first cleanup step before adding a sleep function
parameter to support also manual_clock.
Also, add a call to BOOST_REQUIRE_EQUAL/BOOST_CHECK_EQUAL,
respectively, to make an error more visible in the test log
since those entry points print the offending values
when not equal.
Signed-off-by: Benny Halevy <bhalevy@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>
Recently, seastar rpc started accepting std::type_identity in addition
to boost::type as a type marker (while labeling the latter with an
ominous deprecation warning). Reduce our depedendency on boost
by switching to std::type_identity.
before this change, these
[convenience libraries](https://www.gnu.org/software/automake/manual/html_node/Libtool-Convenience-Libraries.html)
were implicitly built as static libraries by default,
but weren't explicitly marked as STATIC in CMake. While this worked
with default settings, it could cause issues if `BUILD_SHARED_LIBS` is
enabled.
So before we are ready for building these components as shared
libraries, let's mark all convenience libraries as STATIC for
consistency and to prevent potential issues before we properly support
shared library builds.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#21274
when building scylla with the standard library from GCC-14.2, shipped by
fedora 41, we have following build failure:
```
/home/kefu/.local/bin/clang++ -DDEBUG -DDEBUG_LSA_SANITIZER -DFMT_SHARED -DSANITIZE -DSCYLLA_BUILD_MODE=debug -DSCYLLA_ENABLE_ERROR_INJECTION -DSEASTAR_API_LEVEL=7 -DSEASTAR_DEBUG -DSEASTAR_DEBUG_PROMISE -DSEASTAR_DEBUG_SHARED_PTR -DSEASTAR_DEFAULT_ALLOCATOR -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SHUFFLE_TASK_QUEUE -DSEASTAR_SSTRING -DSEASTAR_TYPE_ERASE_MORE -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"Debug\" -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 -isystem /home/kefu/dev/scylladb/abseil -g -Og -g -gz -std=gnu++23 -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-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb/build=. -march=x86-64-v3 -mpclmul -Xclang -fexperimental-assignment-tracking=disabled -Werror=unused-result -fstack-clash-protection -fsanitize=address -fsanitize=undefined -MD -MT CMakeFiles/scylla-main.dir/Debug/init.cc.o -MF CMakeFiles/scylla-main.dir/Debug/init.cc.o.d -o CMakeFiles/scylla-main.dir/Debug/init.cc.o -c /home/kefu/dev/scylladb/init.cc
In file included from /home/kefu/dev/scylladb/init.cc:12:
In file included from /home/kefu/dev/scylladb/db/config.hh:20:
In file included from /home/kefu/dev/scylladb/locator/abstract_replication_strategy.hh:26:
/home/kefu/dev/scylladb/locator/tablets.hh:410:30: error: unexpected type name 'size_t': expected expression
410 | return boost::irange<size_t>(0, tablet_count()) | boost::adaptors::transformed([] (size_t i) {
| ^
/home/kefu/dev/scylladb/locator/tablets.hh:410:23: error: no member named 'irange' in namespace 'boost'
410 | return boost::irange<size_t>(0, tablet_count()) | boost::adaptors::transformed([] (size_t i) {
| ~~~~~~~^
/home/kefu/dev/scylladb/locator/tablets.hh:410:38: error: left operand of comma operator has no effect [-Werror,-Wunused-value]
410 | return boost::irange<size_t>(0, tablet_count()) | boost::adaptors::transformed([] (size_t i) {
| ^
3 errors generated.
[16/782] Building CXX object CMakeFiles/scylla-main.dir/Debug/keys.cc.o
[17/782] Building CXX object CMakeFiles/scylla-main.dir/Debug/counters.cc.o
[18/782] Building CXX object CMakeFiles/scylla-main.dir/Debug/partition_slice_builder.cc.o
[19/782] Building CXX object CMakeFiles/scylla-main.dir/Debug/mutation_query.cc.o
FAILED: CMakeFiles/scylla-main.dir/Debug/mutation_query.cc.o
/home/kefu/.local/bin/clang++ -DDEBUG -DDEBUG_LSA_SANITIZER -DFMT_SHARED -DSANITIZE -DSCYLLA_BUILD_MODE=debug -DSCYLLA_ENABLE_ERROR_INJECTION -DSEASTAR_API_LEVEL=7 -DSEASTAR_DEBUG -DSEASTAR_DEBUG_PROMISE -DSEASTAR_DEBUG_SHARED_PTR -DSEASTAR_DEFAULT_ALLOCATOR -DSEASTAR_LOGGER_COMPILE_TIME_FMT -DSEASTAR_LOGGER_TYPE_STDOUT -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_SHUFFLE_TASK_QUEUE -DSEASTAR_SSTRING -DSEASTAR_TYPE_ERASE_MORE -DXXH_PRIVATE_API -DCMAKE_INTDIR=\"Debug\" -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 -isystem /home/kefu/dev/scylladb/abseil -g -Og -g -gz -std=gnu++23 -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-unused-parameter -ffile-prefix-map=/home/kefu/dev/scylladb/build=. -march=x86-64-v3 -mpclmul -Xclang -fexperimental-assignment-tracking=disabled -Werror=unused-result -fstack-clash-protection -fsanitize=address -fsanitize=undefined -MD -MT CMakeFiles/scylla-main.dir/Debug/mutation_query.cc.o -MF CMakeFiles/scylla-main.dir/Debug/mutation_query.cc.o.d -o CMakeFiles/scylla-main.dir/Debug/mutation_query.cc.o -c /home/kefu/dev/scylladb/mutation_query.cc
In file included from /home/kefu/dev/scylladb/mutation_query.cc:12:
In file included from /home/kefu/dev/scylladb/schema/schema_registry.hh:17:
In file included from /home/kefu/dev/scylladb/replica/database.hh:11:
In file included from /home/kefu/dev/scylladb/locator/abstract_replication_strategy.hh:26:
/home/kefu/dev/scylladb/locator/tablets.hh:410:30: error: unexpected type name 'size_t': expected expression
410 | return boost::irange<size_t>(0, tablet_count()) | boost::adaptors::transformed([] (size_t i) {
| ^
/home/kefu/dev/scylladb/locator/tablets.hh:410:23: error: no member named 'irange' in namespace 'boost'
410 | return boost::irange<size_t>(0, tablet_count()) | boost::adaptors::transformed([] (size_t i) {
| ~~~~~~~^
/home/kefu/dev/scylladb/locator/tablets.hh:410:38: error: left operand of comma operator has no effect [-Werror,-Wunused-value]
410 | return boost::irange<size_t>(0, tablet_count()) | boost::adaptors::transformed([] (size_t i) {
| ^
In file included from /home/kefu/dev/scylladb/mutation_query.cc:12:
In file included from /home/kefu/dev/scylladb/schema/schema_registry.hh:17:
In file included from /home/kefu/dev/scylladb/replica/database.hh:37:
In file included from /home/kefu/dev/scylladb/db/snapshot-ctl.hh:20:
/home/kefu/dev/scylladb/tasks/task_manager.hh:403:54: error: no member named 'irange' in namespace 'boost'
403 | co_await coroutine::parallel_for_each(boost::irange(0u, smp::count), [&tm, id, &res, &func] (unsigned shard) -> future<> {
| ~~~~~~~^
4 errors generated.
```
so let's take the opportunity to switch from `boost::irange` to
`std::views::iota`.
in this change, we:
- switch from boost::irange to std::views::iota for better standard library compatibility
- retain boost::irange where step parameter is used, as std::views::iota doesn't support it
- this change partially modernizes our range usage while maintaining
- existing functionality
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#20924
before this change, we rely on `using namespace seastar` to use
`seastar::format()` without qualifying the `format()` with its
namespace. this works fine until we changed the parameter type
of format string `seastar::format()` from `const char*` to
`fmt::format_string<...>`. this change practically invited
`seastar::format()` to the club of `std::format()` and `fmt::format()`,
where all members accept a templated parameter as its `fmt`
parameter. and `seastar::format()` is not the best candidate anymore.
despite that argument-dependent lookup (ADT for short) favors the
function which is in the same namespace as its parameter, but
`using namespace` makes `seastar::format()` more competitive,
so both `std::format()` and `seastar::format()` are considered
as the condidates.
that is what is happening scylladb in quite a few caller sites of
`format()`, hence ADT is not able to tell which function the winner
in the name lookup:
```
/__w/scylladb/scylladb/mutation/mutation_fragment_stream_validator.cc:265:12: error: call to 'format' is ambiguous
265 | return format("{} ({}.{} {})", _name_view, s.ks_name(), s.cf_name(), s.id());
| ^~~~~~
/usr/bin/../lib/gcc/x86_64-redhat-linux/14/../../../../include/c++/14/format:4290:5: note: candidate function [with _Args = <const std::basic_string_view<char> &, const seastar::basic_sstring<char, unsigned int, 15> &, const seastar::basic_sstring<char, unsigned int, 15> &, const utils::tagged_uuid<table_id_tag> &>]
4290 | format(format_string<_Args...> __fmt, _Args&&... __args)
| ^
/__w/scylladb/scylladb/seastar/include/seastar/core/print.hh:143:1: note: candidate function [with A = <const std::basic_string_view<char> &, const seastar::basic_sstring<char, unsigned int, 15> &, const seastar::basic_sstring<char, unsigned int, 15> &, const utils::tagged_uuid<table_id_tag> &>]
143 | format(fmt::format_string<A...> fmt, A&&... a) {
| ^
```
in this change, we
change all `format()` to either `fmt::format()` or `seastar::format()`
with following rules:
- if the caller expects an `sstring` or `std::string_view`, change to
`seastar::format()`
- if the caller expects an `std::string`, change to `fmt::format()`.
because, `sstring::operator std::basic_string` would incur a deep
copy.
we will need another change to enable scylladb to compile with the
latest seastar. namely, to pass the format string as a templated
parameter down to helper functions which format their parameters.
to miminize the scope of this change, let's include that change when
bumping up the seastar submodule. as that change will depend on
the seastar change.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
With implicit conversion of tagged integers to untagged ones going away,
explicitly tag (or untag, as necessary) the operands of the following
operations, in "test/raft/randomized_nemesis_test.cc":
- addition of tagged and untagged (both should be tagged)
- taking the minimum of an index difference and a container size (both
should be untagged)
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
With implicit conversion of tagged integers to untagged ones going away,
unpack and clean up the relatively complex
first_to_remain = max(snap.idx + 1 - preserve_log_entries, 0)
calculation in persistence::store_snapshot().
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
With implicit conversion of tagged integers to untagged ones going away,
explicitly untag the operands / arguments of the following operations, in
"test/raft/replication.hh":
- assignment to raft_cluster::_seen
- call to hasher_int::hash_range()
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
raft_cluster::get_states() passes a "start_idx" to create_log(), and
create_log() uses it as an "index_t" object. Match the type of "start_idx"
to its name.
This patch is best viewed with "git show -W".
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
In test_case::get_first_val(), the asssignment
first_val = initial_snapshots[initial_leader].snap.idx;
*both* relies on implicit conversion of the tagged integer type "index_t"
to the underlying "uint64_t", *and* is a logic bug, as reported at
<https://github.com/scylladb/scylladb/issues/20151>.
For now, wean the buggy asssignment off the disappearing
tagged-to-untaggged conversion.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
Properly annotate index_t and term_t constants for use in
BOOST_CHECK_EQUAL() and BOOST_CHECK().
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
Properly annotate index_t and term_t constants for use in
BOOST_CHECK_EQUAL(), BOOST_CHECK(). Clean up the first args of
read_quorum() calls -- stay in term_t space.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
The "from" and "to" parameters of compare_log_entries() are raft log
indices; change them to raft::index_t, and update the callers.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
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
The direct failure detector design is simplistic. It sends pings
sequentially and times out listeners that reached the threshold (i.e.
didn't hear from a given endpoint for too long) in-between pings.
Given the sequential nature, the previous ping must finish so the next
ping can start. We timeout pings that take too long. The timeout was
hardcoded and set to 300ms. This is too low for wide-area setups --
latencies across the Earth can indeed go up to 300ms. 3 subsequent timed
out pings to a given node were sufficient for the Raft listener to "mark
server as down" (the listener used a threshold of 1s).
Increase the ping timeout to 600ms which should be enough even for
pinging the opposite side of Earth, and make it tunable.
Increase the Raft listener threshold from 1s to 2s. Without the
increased threshold, one timed out ping would be enough to mark the
server as down. Increasing it to 2s requires 3 timed out pings which
makes it more robust in presence of transient network hiccups.
In the future we'll most likely want to decrease the Raft listener
threshold again, if we use Raft for data path -- so leader elections
start quickly after leader failures. (Faster than 2s). To do that we'll
have to improve the design of the direct failure detector.
Ref: scylladb/scylladb#16410Fixes: scylladb/scylladb#16607
---
I tested the change manually using `tc qdisc ... netem delay`, setting
network delay on local setup to ~300ms with jitter. Without the change,
the result is as observed in scylladb/scylladb#16410: interleaving
```
raft_group_registry - marking Raft server ... as dead for Raft groups
raft_group_registry - marking Raft server ... as alive for Raft groups
```
happening once every few seconds. The "marking as dead" happens whenever
we get 3 subsequent failed pings, which is happens with certain (high)
probability depending on the latency jitter. Then as soon as we get a
successful ping, we mark server back as alive.
With the change, the phenomenon no longer appears.
Closesscylladb/scylladb#18443
since we do not rely on FMT_DEPRECATED_OSTREAM to define the
fmt::formatter for us anymore, let's stop defining `FMT_DEPRECATED_OSTREAM`.
in this change,
* utils: drop the range formatters in to_string.hh and to_string.c, as
we don't use them anymore. and the tests for them in
test/boost/string_format_test.cc are removed accordingly.
* utils: use fmt to print chunk_vector and small_vector. as
we are not able to print the elements using operator<< anymore
after switching to {fmt} formatters.
* test/boost: specialize fmt::details::is_std_string_like<bytes>
due to a bug in {fmt} v9, {fmt} fails to format a range whose
element type is `basic_sstring<uint8_t>`, as it considers it
as a string-like type, but `basic_sstring<uint8_t>`'s char type
is signed char, not char. this issue does not exist in {fmt} v10,
so, in this change, we add a workaround to explicitly specialize
the type trait to assure that {fmt} format this type using its
`fmt::formatter` specialization instead of trying to format it
as a string. also, {fmt}'s generic ranges formatter calls the
pair formatter's `set_brackets()` and `set_separator()` methods
when printing the range, but operator<< based formatter does not
provide these method, we have to include this change in the change
switching to {fmt}, otherwise the change specializing
`fmt::details::is_std_string_like<bytes>` won't compile.
* test/boost: in tests, we use `BOOST_REQUIRE_EQUAL()` and its friends
for comparing values. but without the operator<< based formatters,
Boost.Test would not be able to print them. after removing
the homebrew formatters, we need to use the generic
`boost_test_print_type()` helper to do this job. so we are
including `test_utils.hh` in tests so that we can print
the formattable types.
* treewide: add "#include "utils/to_string.hh" where
`fmt::formatter<optional<>>` is used.
* configure.py: do not define FMT_DEPRECATED_OSTREAM
* cmake: do not define FMT_DEPRECATED_OSTREAM
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@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
This reverts commit 97b203b1af.
since Seastar provides the formatter, it's not necessary to vendor it in
scylladb anymore.
Refs #13245Closesscylladb/scylladb#18114
before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
also, it's impossible to partial specialize a nested type of a
template class, we cannot specialize the `fmt::formatter` for
`stop_crash<M>::result_type`, as a workaround, a new type is
added.
in this change,
* define a new type named `stop_crash_result`
* add fmt::formatter for `stop_crash_result`
* define stop_crash::result_type as an alias of `stop_crash_result`
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#18018
