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 patch changes get_unlimited_query_max_result_size():
* Also set the page-size field, not just the soft/hard limits
* Renames it to get_query_max_result_size()
* Update callers, specifically storage_proxy::get_max_result_size(),
which now has a much simpler common return path and has to drop the
page size on one rare return path.
This is a purely mechanical change, no behaviour is changed.
When reading a list of ranges with tablets, we don't need a multishard
reader. Instead, we intersect the range list with the local nodes tablet
ranges, then read each range from the respective shard.
The individual ranges are read sequentially, with
database::query[_mutations](), merging the results into a single
instance. This makes the code simple. For tablets,
multishard_mutation_query.cc is no longer on the hot paths, range scans
on tables with tablets fork off to a different code-path in the
coordinator. The only code using multishard_mutation_query.cc are
forced, replica-local scans, like those used by SELECT * FROM
MUTATION_FRAGMENTS(). These are mainly used for diagnostics and tests,
so we optimize for simplicity, not performance.
This param was used by the query-result builder, to set the
last-position on end-of-stream. Instead, do this via a new ResultBuilder
method, maybe_set_last_position(), which is called from read_page(),
which has access to the compaction-state.
With this, the ResultBuilder can be created without a compaction-state
at hand. This will be important in the next patch.
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
`read_context::dismantle_buffer_stats`, and drop its operator<<.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#17389
get0() dates back from the days where Seastar futures carried tuples, and
get0() was a way to get the first (and usually only) element. Now
it's a distraction, and Seastar is likely to deprecate and remove it.
Replace with seastar::future::get(), which does the same thing.
Store schema_ptr in reader permit instead of storing a const pointer to
schema to ensure that the schema doesn't get changed elsewhere when the
permit is holding on to it. Also update the constructors and all the
relevant callers to pass down schema_ptr instead of a raw pointer.
Fixes#16180
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Closesscylladb/scylladb#16658
seastar::logger is using the compile-time format checking by default if
compiled using {fmt} 8.0 and up. and it requires the format string to be
consteval string, otherwise we have to use `fmt::runtime()` explicitly.
so adapt the change, let's use the consteval string when formatting
logging messages.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closesscylladb/scylladb#16612
Previously semaphore mismatch was checked only in multi-partition
queries and if happened, an internal error was thrown.
This commit pushed the check down to `querier_cache`, so each
`lookup_*_querier` method will check for the mismatch.
What's more, if semaphore mismatch occurs, check whether both semaphores belong
to user. If so, log a warning and drop cached reader instead of
throwing an error.
The mismatch can happen if user's scheduling group changed during
a query. We don't want to throw an error then, but drop and reset
cached reader.
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 is not strictly necessary, as the multishard reader will be later
avoided altogether for tablet-based tables, but it is a step towards
converting all code to use the erm->get_sharder() instead of
schema::get_sharder().
In that level no io_priority_class-es exist. Instead, all the IO happens
in the context of current sched-group. File API no longer accepts prio
class argument (and makes io_intent arg mandatory to impls).
So the change consists of
- removing all usage of io_priority_class
- patching file_impl's inheritants to updated API
- priority manager goes away altogether
- IO bandwidth update is performed on respective sched group
- tune-up scylla-gdb.py io_queues command
The first change is huge and was made semi-autimatically by:
- grep io_priority_class | default_priority_class
- remove all calls, found methods' args and class' fields
Patching file_impl-s is smaller, but also mechanical:
- replace io_priority_class& argument with io_intent* one
- pass intent to lower file (if applicatble)
Dropping the priority manager is:
- git-rm .cc and .hh
- sed out all the #include-s
- fix configure.py and cmakefile
The scylla-gdb.py update is a bit hairry -- it needs to use task queues
list for IO classes names and shares, but to detect it should it checks
for the "commitlog" group is present.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Closes#13963
With regards to closing the looked-up querier if an exception is thrown.
In particular, this requires closing the querier if a semaphore mismatch
is detected. Move the table lookup above the line where the querier is
looked up, to avoid having to handle the exception from it.
To make sure all tracing done on a certain page will make its way into
the appropriate trace session.
This is a contination of the previous patch (which added trace pointer
to the permit).
And propagate it down to where it is created. This will be used to add
trace points for semaphore related events, but this will come in the
next patches.
these warnings are found by Clang-17 after removing
`-Wno-unused-lambda-capture` and '-Wno-unused-variable' from
the list of disabled warnings in `configure.py`.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Schema related files are moved there. This excludes schema files that
also interact with mutations, because the mutation module depends on
the schema. Those files will have to go into a separate module.
Closes#12858
The query result writer now counts tombstones and cuts the page (marking
it as a short one) when the tombstone limit is reached. This is to avoid
timing out on large span of tombstones, especially prefixes.
In the case of unpaged queries, we fail the read instead, similarly to
how we do with max result size.
If the limit is 0, the previous behaviour is used: tombstones are not
taken into consideration at all.
detach_state() allows the user to resume a compaction process later,
without having to keep the compactor object alive. This happens by
generating and returning the mutation fragments the user has to re-feed
to a newly constructed compactor to bring it into the exact same state
the current compactor was at the point of stopping the compaction.
This state includes the partition-header (partition-start and static-row
if any) and the currently active range tombstone.
Detaching the state is pointless however when the compaction was stopped
such that the currently compacted partition was completely exhausted.
Allowing the state to be detached in this case seems benign but it
caused a subtle bug in the main user of this feature: the partition
range scan algorithm, where the fragments included in the detached state
were pushed back into the reader which produced them. If the partition
happened to be exhausted -- meaning the next fragment in the reader was
a partition-start or EOS -- this resulted in the partition being
re-emitted later without a partition-end, resulting in corrupt
query-result being generated, in turn resulting in an obscure "IDL frame
truncated" error.
This patch solves this seemingly benign but sinister bug by making the
return value of `detach_state()` an std::optional and returning a
disengaged optional when the partition was exhausted.
Instead of a separate partition key and position-in-partition.
This continues the recently started effort to standardize storing of
full positions on `full_position`.
This patch is also a hidden preparation for read_context::save_readers()
multishard_mutation_query.cc) no longer being able to get partition key
from compaction state in the future.
This reverts commit c3bad157e5, reversing
changes made to e66809d051. The checks it
adds are triggered by some dtests. While it's possible the check is
triggered due to an existing problem, better to investigate it out-of-tree.
Fixes#11169.
detach_state() allows the user to resume a compaction process later,
without having to keep the compactor object alive. This happens by
generating and returning the mutation fragments the user has to re-feed
to a newly constructed compactor to bring it into the exact same state
the current compactor was at the point of stopping the compaction.
This state includes the partition-header (partition-start and static-row
if any) and the currently active range tombstone.
Detaching the state is pointless however when the compaction was stopped
such that the currently compacted partition was completely exhausted.
Allowing the state to be detached in this case seems benign but it
caused a subtle bug in the main user of this feature: the partition
range scan algorithm, where the fragments included in the detached state
were pushed back into the reader which produced them. If the partition
happened to be exhausted -- meaning the next fragment in the reader was
a partition-start or EOS -- this resulted in the partition being
re-emitted later without a partition-end, resulting in corrupt
query-result being generated, in turn resulting in an obscure "IDL frame
truncated" error.
This patch solves this seemingly benign but sinister bug by making the
return value of `detach_state()` an std::optional and returning a
disengaged optional when the partition was exhausted.
Instead of a separate partition key and position-in-partition.
This continues the recently started effort to standardize storing of
full positions on `full_position`.
This patch is also a hidden preparation for read_context::save_readers()
multishard_mutation_query.cc) no longer being able to get partition key
from compaction state in the future.
Now that we use emit_only_live_rows::no everywhere we can remove this
template parameters. Only the template parameter is removed, the
internal logic around it is left in place (will be removed in a next
patch), by hard-wiring `only_live()`.
emit_only_live_rows is a convenience so downstream consumers of the
mutation compactors don't have to check the `bool is_live` already
passed to them. This convenience however causes a template parameter and
additional logic for the compactor. As the most prominent of these
consumers (the query result builder) will soon have to switch to
emit_only_live_rows::no for other reasons anyway (it will want to count
tombstones), we take the opportunity to switch everybody to ::no. This
can be done with very little additional complexity to these consumer --
basically an additional if or two.
This prepares the ground for removing this template parameter and the
associate logic from the compactor.
Soon, the currently two distinct types of queriers will be merged, as
the template parameter differentiating them will be gone. This will make
using type based overload for insert() impossible, as 2 out of the 3
types will be the same. Use different names instead.
Use the recently introduced query-result facility to have the replica
set the position where the query should continue from. For now this is
the same as what the implicit position would have been previously (last
row in result), but it opens up the possibility to stop the query at a
dead row.
Currently the result builder is created two frames above the method in
which actually needed. Push down a factory method instead and create it
where actually used. This allows us to pass it arguments that are
present only in the method which uses it.
Optimize error handling by preventing
exception try/catch using coroutine::as_future
to get query::consume_page's result.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
And use smp::invoke_on_all rather than a home-brewed
version of parallel_for_each over all shard ids.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Sot it can be co_awaited efficiently using coroutine::as_future,
othwise, any exceptions will escape `as_future`.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
No need to call _db.invoke_on inside a parallel_for_each
loop over all shards. Just use _db.invoke_on_all instead.
Besides that, there's no need for a .then continuation
for assigning the per-shard reader in _readers[shard].
It can be done by the functor running on each db shard.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
lookup_readers might fail after populating some readers
and those better be closed before returning the exception.
Fixes#10351
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closes#10425
The change is mostly mechanical: update all compactor instances to the
_v2 variant and update all call-sites, of which there is not that many.
As a consequence of this patch, queries -- both single-partition and
range-scans -- now do the v2->v1 conversion in the consumers, instead of
in the compactor.
