In mutation_reader_merger and clustering_order_reader_merger, the
operator()() is responsible for producing mutation fragments that will
be merged and pushed to the combined reader's buffer. Sometimes, it
might have to advance existing readers, open new and / or close some
existing ones, which requires calling a helper method and then calling
operator()() recursively.
In some unlucky circumstances, a stack overflow can occur:
- Readers have to be opened incrementally,
- Most or all readers must not produce any fragments and need to report
end of stream without preemption,
- There has to be enough readers opened within the lifetime of the
combined reader (~500),
- All of the above needs to happen within a single task quota.
In order to prevent such a situation, the code of both reader merger
classes were modified not to perform recursion at all. Most of the code
of the operator()() was moved to maybe_produce_batch which does not
recur if it is not possible for it to produce a fragment, instead it
returns std::nullopt and operator()() calls this method in a loop via
seastar::repeat_until_value.
A regression test is added.
Fixes: scylladb/scylladb#14415
Closes#14452
The evictable reader must ensure that each buffer fill makes forward
progress, i.e. the last fragment in the buffer has a position larger
than the last fragment from the previous buffer-fill. Otherwise, the
reader could get stuck in an infinite loop between buffer fills, if the
reader is evicted in-between.
The code guranteeing this forward progress had a bug: the comparison
between the position after the last buffer-fill and the current
last fragment position was done in the wrong direction.
So if the condition that we wanted to achieve was already true, we would
continue filling the buffer until partition end which may lead to OOMs
such as in #13491.
There was already a fix in this area to handle `partition_start`
fragments correctly - #13563 - but it missed that the position
comparison was done in the wrong order.
Fix the comparison and adjust one of the tests (added in #13563) to
detect this case.
Fixes#13491
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
CWG 2631 (https://cplusplus.github.io/CWG/issues/2631.html) reports
an issue on how the default argument is evaluated. this problem is
more obvious when it comes to how `std::source_location::current()`
is evaluated as a default argument. but not all compilers have the
same behavior, see https://godbolt.org/z/PK865KdG4.
notebaly, clang-15 evaluates the default argument at the callee
site. so we need to check the capability of compiler and fall back
to the one defined by util/source_location-compat.hh if the compiler
suffers from CWG 2631. and clang-16 implemented CWG2631 in
https://reviews.llvm.org/D136554. But unfortunately, this change
was not backported to clang-15.
before switching over to clang-16, for using std::source_location::current()
as the default parameter and expect the behavior defined by CWG2631,
we have to use the compatible layer provided by Seastar. otherwise
we always end up having the source_location at the callee side, which
is not interesting under most circumstances.
so in this change, all places using the idiom of passing
std::source_location::current() as the default parameter are changed
to use seastar::compat::source_location::current(). despite that
we have `#include "seastarx.h"` for opening the seastar namespace,
to disambiguate the "namespace compat" defined somewhere in scylladb,
the fully qualified name of
`seastar::compat::source_location::current()` is used.
see also 09a3c63345, where we used
std::source_location as an alias of std::experimental::source_location
if it was available. but this does not apply to the settings of our
current toolchain, where we have GCC-12 and Clang-15.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#14086
As described in https://github.com/scylladb/scylladb/issues/8638,
we're moving away from `SimpleStrategy`, in the future
it will become deprecated.
We should remove all uses of it and replace them
with `NetworkTopologyStrategy`.
This change replaces `SimpleStrategy` with
`NetworkTopologyStrategy` in all unit tests,
or at least in the ones where it was reasonable to do so.
Some of the tests were written explicitly to test the
`SimpleStrategy` strategy, or changing the keyspace from
`SimpleStrategy` to `NetworkTopologyStrategy`.
These tests were left intact.
It's still a feature that is supported,
even if it's slowly getting deprecated.
The typical way to use `NetworkTopologyStrategy` is
to specify a replication factor for each datacenter.
This could be a bit cumbersome, we would have to fetch
the list of datacenters, set the repfactors, etc.
Luckily there is another way - we can just specify
a replication factor to use for or each existing
datacenter, like this:
```cql
CREATE KEYSPACE {} WITH REPLICATION =
{'class' : 'NetworkTopologyStrategy', 'replication_factor' : 1};
```
This makes the change rather straightforward - just replace all
instances of `'SimpleStrategy'', with `'NetworkTopologyStrategy'`.
Refs: https://github.com/scylladb/scylladb/issues/8638
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
Closes#13990
The evictable reader must ensure that each buffer fill makes forward
progress, i.e. the last fragment in the buffer has a position larger
than the last fragment from the last buffer-fill. Otherwise, the reader
could get stuck in an infinite loop between buffer fills, if the reader
is evicted in-between.
The code guranteeing this forward change has a bug: when the next
expected position is a partition-start (another partition), the code
would loop forever, effectively reading all there is from the underlying
reader.
To avoid this, add a special case to ignore the progress guarantee loop
altogether when the next expected position is a partition start. In this
case, progress is garanteed anyway, because there is exactly one
partition-start fragment in each partition.
Fixes: #13491Closes#13563
No point in going through the vector<mutation> entry-point
just to discover in run time that it was called
with a single-element vector, when we know that
in advance.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closes#13733
enable_optimized_twcs_queries is specific to TWCS, therefore it
belongs to TWCS, not replica::table.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Closes#13489
Preparing for #10459, this series defines sstables::generation_type::int_t
as `int64_t` at the moment and use that instead of naked `int64_t` variables
so it can be changed in the future to hold e.g. a `std::variant<int64_t, sstables::generation_id>`.
sstables::new_generation was defined to generation new, unique generations.
Currently it is based on incrementing a counter, but it can be extended in the future
to manufacture UUIDs.
The unit tests are cleaned up in this series to minimize their dependency on numeric generations.
Basically, they should be used for loading sstables with hard coded generation numbers stored under `test/resource/sstables`.
For all the rest, the tests should use existing and mechanisms introduced in this series such as generation_factory, sst_factory and smart make_sstable methods in sstable_test_env and table_for_tests to generate new sstables with a unique generation, and use the abstract sst->generation() method to get their generation if needed, without resorting the the actual value it may hold.
Closes#12994
* github.com:scylladb/scylladb:
everywhere: use sstables::generation_type
test: sstable_test_env: use make_new_generation
sstable_directory::components_lister::process: fixup indentation
sstables: make highest_generation_seen return optional generation
replica: table: add make_new_generation function
replica: table: move sstable generation related functions out of line
test: sstables: use generation_type::int_t
sstables: generation_type: define int_t
Use generation_type rather than generation_type::int_t
where possible and removed the deprecated
functions accepting the int_t.i
Ref #10459
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Convert all users to use sstables::generation_type::int_t.
Further patches will continue to convert most to
using sstables::generation_type instead so we can
abstract the value type.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
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.
The tests extensively use a `std::function<shared_sstable()>`
to generate new tables.
Rather than handcrafting them all over the place,
let sstable_test_env return such factory given a schema
(and another entry point that also gets a version)
and that uses the embedded generation_factory in the test_env
to generate new sstables with unique generations.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Rather than maintaining a running generation number,
use the default env.make_sstable(s) in sst_factory
and collect the expected generations from the resulting
shared sstable.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
For generating shared_sstables with increasing generations
(using the test_env make_sstable generations) and a given level.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Tests should just generate the highest sstable version
available. There is no need to ontinue testing old versions,
in particular partially supported ones like "la".
Use also the default values for sstable::format_types, buffer_size,
etc. if there's no particular need to override them.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
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
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
We currently have two method families to generate partition keys:
* make_keys() in test/lib/simple_schema.hh
* token_generation_for_shard() in test/lib/sstable_utils.hh
Both work only for schemas with a single partition key column of `text` type and both generate keys of fixed size.
This is very restrictive and simplistic. Tests, which wanted anything more complicated than that had to rely on open-coded key generation.
Also, many tests started to rely on the simplistic nature of these keys, in particular two tests started failing because the new key generation method generated keys of varying size:
* sstable_compaction_test.sstable_run_based_compaction_test
* sstable_mutation_test.test_key_count_estimation
These two tests seems to depend on generated keys all being of the same size. This makes some sense in the case of the key count estimation test, but makes no sense at all to me in the case of the sstable run test.
Closes#12657
* github.com:scylladb/scylladb:
test/lib/sstable_utils: remove now unused token_generation_for_shard() and friends
test/lib/simple_schema: remove now unused make_keys() and friends
test: migrate to tests::generate_partition_key[s]()
test/lib/test_services: add table_for_tests::make_default_schema()
test/lib: add key_utils.hh
test/lib/random_schema.hh: value_generator: add min_size_in_bytes
We have enabled the command line options without changing a
single line of code, we only had to replace old include
with scylla_test_case.hh.
Next step is to add x-log-compaction-groups options, which will
determine the number of compaction groups to be used by all
instantiations of replica::table.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Use the newly introduced key generation facilities, instead of the the
old inflexible alternatives and hand-rolled code.
Most of the migrations are mechanic, but there are two tests that
were tricky to migrate:
* sstable_compaction_test.sstable_run_based_compaction_test
* sstable_mutation_test.test_key_count_estimation
These two tests seems to depend on generated keys all being of the same
size. This makes some sense in the case of the key count estimation
test, but makes no sense at all to me in the case of the sstable run
test.
This fixes a long standing bug related to handling of non-full
clustering keys, issue #1446.
after_key() was creating a position which is after all keys prefixed
by a non-full key, rather than a position which is right after that
key.
This will issue will be caught by cql_query_test::test_compact_storage
in debug mode when mutation_partition_v2 merging starts inserting
sentinels at position after_key() on preemption.
It probably already causes problems for such keys.
trim_clustering_row_ranges_to() is broken for non-full keys in reverse
mode. It will trim the range to
position_in_partition_view::after_key(full_key) instead of
position_in_partition_view::before_key(key), hence it will include the
key in the resulting range rather than exclude it.
Fixes#12180
Refs #1446
Mainly this PR removes global db::config and feature service that are used by sstables::test_env as dependencies for embedded sstables_manager. Other than that -- drop unused methods, remove nested test_env-s and relax few cases that use two temp dirs at a time for no gain.
Closes#12155
* github.com:scylladb/scylladb:
test, utils: Use only one tempdir
sstable_compaction_test: Dont create nested envs
mutation_reader_test: Remove unused create_sstable() helper
tests, lib: Move globals onto sstables::test_env
tests: Use sstables::test_env.db_config() to access config
features: Mark feature_config_from_db_config const
sstable_3_x_test: Use env method to create sst
sstable_3_x_test: Indentation fix after previous patch
sstable_3_x_test: Use sstable::test_env
test: Add config to sstable::test_env creation
config: Add constexpr value for default murmur ignore bits
`generation_type` is (supposed to be) conceptually different from
`int64_t` (even if physically they are the same), but at present
Scylla code still largely treats them interchangeably.
In addition to using `generation_type` in more places, we
provide (no-op) `generation_value()` and `generation_from_value()`
operations to make the smoke-and-mirrors more believable.
The churn is considerable, but all mechanical. To avoid even
more (way, way more) churn, unit test code is left untreated for
now, except where it uses the affected core APIs directly.
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
The compacting reader created using make_compacting_reader() was not
dropping range_tombstone_change fragments which were shadowed by the
partition tombstones. As a result the output fragment stream was not
minimal.
Lack of this change would cause problems in unit tests later in the
series after the change which makes memtables lazily compact partition
versions. In test_reverse_reader_reads_in_native_reverse_order we
compare output of two readers, and assume that compacted streams are
the same. If compacting reader doesn't produce minimal output, then
the streams could differ if one of them went through the compaction in
the memtable (which is minimal).
This reverts commit e0670f0bb5, reversing
changes made to 605ee74c39. It causes failures
in debug mode in
database_test.test_database_with_data_in_sstables_is_a_mutation_source_plain,
though with low probability.
Fixes#10780Reopens#652.
The compacting reader created using make_compacting_reader() was not
dropping range_tombstone_change fragments which were shadowed by the
partition tombstones. As a result the output fragment stream was not
minimal.
Lack of this change would cause problems in unit tests later in the
series after the change which makes memtables lazily compact partition
versions. In test_reverse_reader_reads_in_native_reverse_order we
compare output of two readers, and assume that compacted streams are
the same. If compacting reader doesn't produce minimal output, then
the streams could differ if one of them went through the compaction in
the memtable (which is minimal).
The only user is row level repair: it is replaced with
downgrade_to_v1(make_empty_flat_reader_v2()). The row level reader has
lots of downgrade_to_v1() calls, we will deal with these later all at
once.
Another use is the empty mutation source, this is trivially converted to
use the v2 variant.
"
First migrate all users to the v2 variant, all of which are tests.
However, to be able to properly migrate all tests off it, a v2 variant
of the restricted reader is also needed. All restricted reader users are
then migrated to the freshly introduced v2 variant and the v1 variant is
removed.
Users include:
* replica::table::make_reader_v2()
* streaming_virtual_table::as_mutation_source()
* sstables::make_reader()
* tests
This allows us to get rid of a bunch of conversions on the query path,
which was mostly v2 already.
With a few tests we did kick the can down the road by wrapping the v2
reader in `downgrade_to_v1()`, but this series is long enough already.
Tests: unit(dev), unit(boost/flat_mutation_reader_test:debug)
"
* 'remove-reader-from-mutations-v1/v3' of https://github.com/denesb/scylla:
readers: remove now unused v1 reader from mutations
test: move away from v1 reader from mutations
test/boost/mutation_reader_test: use fragment_scatterer
test/boost/mutation_fragment_test: extract fragment_scatterer into a separate hh
test/boost: mutation_fragment_test: refactor fragment_scatterer
readers: remove now unused v1 reversing reader
test/boost/flat_mutation_reader_test: convert to v2
frozen_mutation: fragment_and_freeze(): convert to v2
frozen_mutation: coroutinize fragment_and_freeze()
readers: migrate away from v1 reversing reader
db/virtual_table: use v2 variant of reversing and forwardable readers
replica/table: use v2 variant of reversing reader
sstables/sstable: remove unused make_crawling_reader_v1()
sstables/sstable: remove make_reader_v1()
readers: add v2 variant of reversing reader
readers/reversing: remove FIXME
readers: reader from mutations: use mutation's own schema when slicing
In most files it was unused. We should move these to the patch which
moved out the last interesting reader from mutation_reader.hh (and added
the corresponding new header include) but its probably not worth the
effort.
Some other files still relied on mutation_reader.hh to provide reader
concurrency semaphore and some other misc reader related definitions.
