users of sstable_set::all() rely on the set itself keeping a reference
to the returned list, so user can iterate through the list assuming
that it is alive all the way through.
this will change in the future though, because there will be a
compound set impl which will have to merge the all() of multiple
managed sets, and the result is a temporary value.
so even range-based loops on all() have to keep a ref to the returned
list, to avoid the list from being prematurely destroyed.
so the following code
for (auto& sst : *sstable_set.all()) { ...}
becomes
for (auto sstables = sstable_set.all(); auto& sst : *sstables) { ... }
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Currently key order validation for the mutation fragment stream
validating filter is all or nothing. Either no keys (partition or
clustering) are validated or all of them. As we suspect that clustering
key order validation would add a significant overhead, this discourages
turning key validation on, which means we miss out on partition key
monotonicity validation which has a much more moderate cost.
This patch makes this configurable in a more fine-grained fashion,
providing separate levels for partition and clustering key monotonicity
validation.
As the choice for the default validation level is not as clear-cut as
before, the default value for the validation level is removed in the
validating filter's constructor.
Commit aab6b0ee27 introduced the
controversial new IMR format, which relied on a very template-heavy
infrastructure to generate serialization and deserialization code via
template meta-programming. The promise was that this new format, beyond
solving the problems the previous open-coded representation had (working
on linearized buffers), will speed up migrating other components to this
IMR format, as the IMR infrastructure reduces code bloat, makes the code
more readable via declarative type descriptions as well as safer.
However, the results were almost the opposite. The template
meta-programming used by the IMR infrastructure proved very hard to
understand. Developers don't want to read or modify it. Maintainers
don't want to see it being used anywhere else. In short, nobody wants to
touch it.
This commit does a conceptual revert of
aab6b0ee27. A verbatim revert is not
possible because related code evolved a lot since the merge. Also, going
back to the previous code would mean we regress as we'd revert the move
to fragmented buffers. So this revert is only conceptual, it changes the
underlying infrastructure back to the previous open-coded one, but keeps
the fragmented buffers, as well as the interface of the related
components (to the extent possible).
Fixes: #5578
sstable_run_based_compaction_test assumed that sstables are freed immediately
after they are fully processed.
Hovewer, since commit b524f96a74,
mutation_reader_merger releases sstables in batches of 4, which breaks the
assumption. This fix adjusts the test accordingly.
Until now, the test only kept working by chance: by coincidence, the number of
test sstables processed by merging_reader in a single fill_buffer() call was
divisible by 4. Since the test checks happen between those calls,
the test never witnessed a situation when an sstable was fully processed,
but not released yet.
The error was noticed during the work on an upcoming patch which changes the
size of mutation_fragment, and reduces the number of test sstables processed
in a single fill_buffer() call, which breaks the test.
Add new scylla_metadata_type::SSTableOrigin.
Store and retrive a sstring to the scylla metadata component.
Pass sstable_writer_config::origin from the mx sstable writer
and ignore it in the k_l writer.
Add unit test to verify the sstable_origin extension
using both empty and a random string.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add a string describing where the sstables originated
from (e.g. memtable, repair, streaming, compaction, etc.)
If configure_writer is called with a nullptr, the origin
will be equal to an empty string.
Introduce test_env_sstables_manager that provides an overload
of configure_writer with no parmeters that calls the base-class'
configure_writer with "test" origin. This was to reduce the
code churn in this patch and to keep the tests simple.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
If possible, test the highest sstable format version,
as it's the mostly used.
If there pre-written sstables we need to load from the
test directory from an older version, either specify their
version explicitly, or use the new test_env::reusable_sst
method that looks up the latest sstable version in the
given directory and generation.
Test: unit(release)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20201210161822.2833510-1-bhalevy@scylladb.com>
"
Without interposer consumer on flush, it could happen that a new sstable,
produced by memtable flush, will not conform to the strategy invariant.
For example, with TWCS, this new sstable could span multiple time windows,
making it hard for the strategy to purge expired data. If interposer is
enabled, the data will be correctly segregated into different sstables,
each one spanning a single window.
Fixes#4617.
tests:
- mode(dev).
- manually tested it by forcing a flush of memtable spanning many windows
"
* 'segregation_on_flush_v2' of github.com:raphaelsc/scylla:
test: Add test for TWCS interposer on memtable flush
table: Wire interposer consumer for memtable flush
table: Add write_memtable_to_sstable variant which accepts flat_mutation_reader
table: Allow sstable write permit to be shared across monitors
memtable: Track min timestamp
table: Extend cache update to operate a memtable split into multiple sstables
The test violates clustering key order on purpose to produce a corrupt
sstable (to test scrub). Disable key validation so when we move the
validator into the writer itself in the next patch it doesn't abort the
test.
The heuristic of STCS reshape is correct, and it built the compaction
descriptor correctly, but forgot to return it to the caller, so no
reshape was ever done on behalf of STCS even when the strategy
needed it.
Fixes#7774.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20201209175044.1609102-1-raphaelsc@scylladb.com>
This reverts commit dc77d128e9. It was reverted
due to a strange and unexplained diff, which is now explained. The
HEAD on the working directory being pulled from was set back, so git
thought it was merging the intended commits, plus all the work that was
committed from HEAD to master. So it is safe to restore it.
This reverts commit 0aa1f7c70a, reversing
changes made to 72c59e8000. The diff is
strange, including unrelated commits. There is no understanding of the
cause, so to be safe, revert and try again.
1. sstables: move `sstable_set` implementations to a separate module
All the implementations were kept in sstables/compaction_strategy.cc
which is quite large even without them. `sstable_set` already had its
own header file, now it gets its own implementation file.
The declarations of implementation classes and interfaces (`sstable_set_impl`,
`bag_sstable_set`, and so on) were also exposed in a header file,
sstable_set_impl.hh, for the purposes of potential unit testing.
2. mutation_reader: move `mutation_reader::forwarding` to flat_mutation_reader.hh
Files which need this definition won't have to include
mutation_reader.hh, only flat_mutation_reader.hh (so the inclusions are
in total smaller; mutation_reader.hh includes flat_mutation_reader.hh).
3. sstables: move sstable reader creation functions to `sstable_set`
Lower level functions such as `create_single_key_sstable_reader`
were made methods of `sstable_set`.
The motivation is that each concrete sstable_set
may decide to use a better sstable reading algorithm specific to the
data structures used by this sstable_set. For this it needs to access
the set's internals.
A nice side effect is that we moved some code out of table.cc
and database.hh which are huge files.
4. sstables: pass `ring_position` to `create_single_key_sstable_reader`
instead of `partition_range`.
It would be best to pass `partition_key` or `decorated_key` here.
However, the implementation of this function needs a `partition_range`
to pass into `sstable_set::select`, and `partition_range` must be
constructed from `ring_position`s. We could create the `ring_position`
internally from the key but that would involve a copy which we want to
avoid.
5. sstable_set: refactor `filter_sstable_for_reader_by_pk`
Introduce a `make_pk_filter` function, which given a ring position,
returns a boolean function (a filter) that given a sstable, tells
whether the sstable may contain rows with the given position.
The logic has been extracted from `filter_sstable_for_reader_by_pk`.
Split from #7437.
Closes#7655
* github.com:scylladb/scylla:
sstable_set: refactor filter_sstable_for_reader_by_pk
sstables: pass ring_position to create_single_key_sstable_reader
sstables: move sstable reader creation functions to `sstable_set`
mutation_reader: move mutation_reader::forwarding to flat_mutation_reader.hh
sstables: move sstable_set implementations to a separate module
For sstable versions greater or equal than md, the `min_max_column_names`
sstable metadata gives a range of position-in-partitions such that all
clustering rows stored in this sstable have positions in this range.
Partition tombstones in this context are understood as covering the
entire range of clustering keys; thus, if the sstable contains at least
one partition tombstone, the sstable position range is set to be the
range of all clustered rows.
Therefore, by checking that the position range is *not* the range of all
clustered rows we know that the sstable cannot have any partition tombstones.
Closes#7678
Lower level functions such as `create_single_key_sstable_reader`
were made methods of `sstable_set`.
The motivation is that each concrete sstable_set
may decide to use a better sstable reading algorithm specific to the
data structures used by this sstable_set. For this it needs to access
the set's internals.
A nice side effect is that we moved some code out of table.cc
and database.hh which are huge files.
The variable 'observer' (an std::optional) may be left uninitialized
if 'incremental_enabled' is false. However, it is used afterwards
with a call to disconnect, accessing garbage.
Fix by accessing it via the optional wrapper. A call to optional::reset()
destroys the observable, which in turn calls disconnect().
Closes#7380
We want to start tracking the memory consumption of mutation fragments.
For this we need schema and permit during construction, and on each
modification, so the memory consumption can be recalculated and pass to
the permit.
In this patch we just add the new parameters and go through the insane
churn of updating all call sites. They will be used in the next patch.
Not used yet, this patch does all the churn of propagating a permit
to each impl.
In the next patch we will use it to track to track the memory
consumption of `_buffer`.
sstables_manager will soon be closed asynhronously, with a future-returning
close() function. To prepare for that, make the following changes
- replace on-stack test_env with test_env::do_with()
- use the variant of column_family_for_tests that accepts an sstables_manager
- replace test_sstables_manager with an sstables_manager obtained from test_env
These changes allow lifetime management of the sstables_manager used
in the tests to be centralized in test_env.
Since test_env now calls await_background_jobs on termination, those
calls are dropped.
The pattern
return function_returning_a_future().get();
is legal, but confusing. It returns an unexpected std::tuple<>. Here,
it doesn't do any harm, but if we try to coerce the surrounding code
into a signature (void ()), then that will fail.
Remove the unneeded and unexpected return.
Stopping a table will soon close its sstables; so the next check will fail
as the number of sstables for the table will be zero.
Reorder the stop() call to make it safe.
We don't need the stop() for the check, since the previous loop made sure
compactions completed.
The database is available at both places that create the options --
tests and API perform_cleanup call.
Options object doesn't over-survive the returned future, so it's
safe to keep the reference on it.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
After 8014c7124, cleanup can potentially pick a compacting SSTable.
Upgrade and scrub can also pick a compacting SSTable.
The problem is that table::candidates_for_compaction() was badly named.
It misleads the user into thinking that the SSTables returned are perfect
candidates for compaction, but manager still need to filter out the
compacting SSTables from the returned set. So it's being renamed.
When the same SSTable is compacted in parallel, the strategy invariant
can be broken like overlapping being introduced in LCS, and also
some deletion failures as more than one compaction process would try
to delete the same files.
Let's fix scrub, cleanup and ugprade by calling the manager function
which gets the correct candidates for compaction.
Fixes#6938.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200811200135.25421-1-raphaelsc@scylladb.com>
C++20 introduced `contains` member functions for maps and sets for
checking whether an element is present in the collection. Previously
`count` function was often used in various ways.
`contains` does not only express the intend of the code better but also
does it in more unified way.
This commit replaces all the occurences of the `count` with the
`contains`.
Tests: unit(dev)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <b4ef3b4bc24f49abe04a2aba0ddd946009c9fcb2.1597314640.git.piotr@scylladb.com>
"
This series adds support for the "md" sstable format.
Support is based on the following:
* do not use clustering based filtering in the presence
of static row, tombstones.
* Disabling min/max column names in the metadata for
formats older than "md".
* When updating the metadata, reset and disable min/max
in the presence of range tombstones (like Cassandra does
and until we process them accurately).
* Fix the way we maintain min/max column names by:
keeping whole clustering key prefixes as min/max
rather than calculating min/max independently for
each component, like Cassandra does in the "md" format.
Fixes#4442
Tests: unit(dev), cql_query_test -t test_clustering_filtering* (debug)
md migration_test dtest from git@github.com:bhalevy/scylla-dtest.git migration_test-md-v1
"
* tag 'md-format-v4' of github.com:bhalevy/scylla: (27 commits)
config: enable_sstables_md_format by default
test: cql_query_test: add test_clustering_filtering unit tests
table: filter_sstable_for_reader: allow clustering filtering md-format sstables
table: create_single_key_sstable_reader: emit partition_start/end for empty filtered results
table: filter_sstable_for_reader: adjust to md-format
table: filter_sstable_for_reader: include non-scylla sstables with tombstones
table: filter_sstable_for_reader: do not filter if static column is requested
table: filter_sstable_for_reader: refactor clustering filtering conditional expression
features: add MD_SSTABLE_FORMAT cluster feature
config: add enable_sstables_md_format
database: add set_format_by_config
test: sstable_3_x_test: test both mc and md versions
test: Add support for the "md" format
sstables: mx/writer: use version from sstable for write calls
sstables: mx/writer: update_min_max_components for partition tombstone
sstables: metadata_collector: support min_max_components for range tombstones
sstable: validate_min_max_metadata: drop outdated logic
sstables: rename mc folder to mx
sstables: may_contain_rows: always true for old formats
sstables: add may_contain_rows
...
C++20 introduced `contains` member functions for maps and sets for
checking whether an element is present in the collection. Previously
the code pattern looked like:
<collection>.find(<element>) != <collection>.end()
In C++20 the same can be expressed with:
<collection>.contains(<element>)
This is not only more concise but also expresses the intend of the code
more clearly.
This commit replaces all the occurences of the old pattern with the new
approach.
Tests: unit(dev)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <f001bbc356224f0c38f06ee2a90fb60a6e8e1980.1597132302.git.piotr@scylladb.com>
Partition tombstones represent an implicit clustering range
that is unbound on both sides, so reflect than in min/max
column names metadata using empty clustering key prefixes.
If we don't do that, when using the sstable for filtering, we have no
other way of distinguishing range tombstones from partition tombstones
given the sstable metadata and we would need to include any sstable
with tombstones, even if those are range tombstone, for which
we can do a better filtering job, using the sstable min/max
column names metadata.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
We essentially treat min/max column names as range bounds
with min as incl_start and max as incl_end.
By generating a bound_view for min/max column names on the fly,
we can correctly track and compare also short clustering
key prefixes that may be used as bounds for range tombstones.
Extend the sstable_tombstone_metadata_check unit test
to cover these cases.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Add the sstable_version_types::md enum value
and logically extend sstable_version_types comparisons to cover
also the > sstable_version_types::mc cases.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently we compare each min/max component independently.
This may lead to suboptimal, inclusive clustering ranges
that do not indicate any actual key we encountered.
For example: ['a', 2], ['b', 1] will lead to min=['a', 1], max=['b', 2]
instead of the keys themselves.
This change keeps the min or max keys as a whole.
It considers shorter clustering prefixes (that are possible with compact
storage) as range tombstone bounds, so that a shorter key is considered
less than the minimum if the latter has a common prefix, and greater
than the maximum if the latter has a common prefix.
Extend the min_max_clustering_key_test to test for this case.
Previously {"a", "2"}, {"b", "1"} clustering keys would erronuously
end up with min={"a", "1"} max={"b", "2"} while we want them to be
min={"a", "2"} max={"b", "1"}.
Adjust sstable_3_x_test to ignore original mc sstables that were
previously computed with different min/max column names.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
"
While working on another patch I was getting odd compiler errors
saying that a call to ::make_shared was ambiguous. The reason was that
seastar has both:
template <typename T, typename... A>
shared_ptr<T> make_shared(A&&... a);
template <typename T>
shared_ptr<T> make_shared(T&& a);
The second variant doesn't exist in std::make_shared.
This series drops the dependency in scylla, so that a future change
can make seastar::make_shared a bit more like std::make_shared.
"
* 'espindola/make_shared' of https://github.com/espindola/scylla:
Everywhere: Explicitly instantiate make_lw_shared
Everywhere: Add a make_shared_schema helper
Everywhere: Explicitly instantiate make_shared
cql3: Add a create_multi_column_relation helper
main: Return a shared_ptr from defer_verbose_shutdown
In some cases estimated number of partitions can be 0, which is albeit a
legit estimation result, breaks many low-level sstable writer code, so
some of these have assertions to ensure estimated partitions is > 0.
To avoid hitting this assert all users of the sstable writers do the
clamping, to ensure estimated partitions is at least 1. However leaving
this to the callers is error prone as #6913 has shown it. As this
clamping is standard practice, it is better to do it in the writers
themselves, avoiding this problem altogether. This is exactly what this
patch does. It also adds two unit tests, one that reproduces the crash
in #6913, and another one that ensures all sstable writers are fine with
estimated partitions being 0 now. Call sites previously doing the
clamping are changed to not do it, it is unnecessary now as the writer
does it itself.
Fixes#6913
Tests: unit(dev)
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20200724120227.267184-1-bdenes@scylladb.com>
seastar::make_lw_shared has a constructor taking a T&&. There is no
such constructor in std::make_shared:
https://en.cppreference.com/w/cpp/memory/shared_ptr/make_shared
This means that we have to move from
make_lw_shared(T(...)
to
make_lw_shared<T>(...)
If we don't want to depend on the idiosyncrasies of
seastar::make_lw_shared.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
This replaces a lot of make_lw_shared(schema(...)) with
make_shared_schema(...).
This makes it easier to drop a dependency on the differences between
seastar::make_shared and std::make_shared.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
needs_cleanup() returns true if a sstable needs cleanup.
Turns out it's very slow because it iterates through all the local
ranges for all sstables in the set, making its complexity:
O(num_sstables * local_ranges)
We can optimize it by taking into account that abstract_replication_strategy
documents that get_ranges() will return a list of ranges that is sorted
and non-overlapping. Compaction for cleanup already takes advantage of that
when checking if a given partition can be actually purged.
So needs_cleanup() can be optimized into O(num_sstables * log(local_ranges)).
With num_sstables=1000, RF=3, then local_ranges=256(num_tokens)*3, it means
the max # of checks performed will go from 768000 to ~9584.
Fixes#6730.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200629171355.45118-2-raphaelsc@scylladb.com>
For tombstone expiration to proceed correctly without the risk of resurrecting
data, the sstable set must be present.
Regular compaction and derivatives provide the sstable set, so they're able
to expire tombstones with no resurrection risk.
Resharding, on the other hand, can run on any shard, not necessarily on the
same shard that one of the input sstables belongs to, so it currently cannot
provide a sstable set for tombstone expiration to proceed safely.
That being said, let's only do expiration based on the presence of the set.
This makes room for the sstable set to be feeded to compaction via descriptor,
allowing even resharding to do expiration. Currently, compaction thinks that
sstable set can only come from the table, and that also needs to be changed
for further flexibility.
It's theoretically possible that a given resharding job will resurrect data if
a fully expired SSTable is resharded at a shard which it doesn't belong to.
Resharding will have no way to tell that expiring all that data will lead to
resurrection because the relevant SSTables are at different shards.
This is fixed by checking for fully expired sstables only on presence of
the sstable set.
Fixes#6600.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200605200954.24696-1-raphaelsc@scylladb.com>
New SStables are only added to backlog tracker if set_unshared() was
called on their behalf. SStables created for streaming are not being
added to the tracker because make_streaming_sstable_for_write()
doesn't call set_unshared() nor does it caller. Which results in backlog
not accounting for their existence, which means backlog will be much
lower than expected.
This problem could be fixed by adding a set_unshared() call but it
turns out we don't even need set_unshared() anymore. It was introduced
when Scylla metadata didn't exist, now a SSTable has built-in knowledge
of whether or not it's shared. Relying on every SSTable creator calling
set_unshared() is bug prone. Let's get rid of it and let the SStable
itself say whether or not it's shared. If an imported SSTable has not
Scylla metadata, Scylla will still be able to compute shards using
token range metadata.
Refs #6021.
Refs #6227.
Fixes#6441.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200512220226.134481-1-raphaelsc@scylladb.com>
"
Currently we classify queries as "system" or "user" based on the table
they target. The class of a query determines how the query is treated,
currently: timeout, limits for reverse queries and the concurrency
semaphore. The catch is that users are also allowed to query system
tables and when doing so they will bypass the limits intended for user
queries. This has caused performance problems in the past, yet the
reason we decided to finally address this is that we want to introduce a
memory limit for unpaged queries. Internal (system) queries are all
unpaged and we don't want to impose the same limit on them.
This series uses scheduling groups to distinguish user and system
workloads, based on the assumption that user workloads will run in the
statement scheduling group, while system workloads will run in the main
(or default) scheduling group, or perhaps something else, but in any
case not in the statement one. Currently the scheduling group of reads
and writes is lost when going through the messaging service, so to be
able to use scheduling groups to distinguish user and system reads this
series refactors the messaging service to retain this distinction across
verb calls. Furthermore, we execute some system reads/writes as part of
user reads/writes, such as auth and schema sync. These processes are
tagged to run in the main group.
This series also centralises query classification on the replica and
moves it to a higher level. More specifically, queries are now
classified -- the scheduling group they run in is translated to the
appropriate query class specific configuration -- on the database level
and the configuration is propagated down to the lower layers.
Currently this query class specific configuration consists of the reader
concurrency semaphore and the max memory limit for otherwise unlimited
queries. A corollary of the semaphore begin selected on the database
level is that the read permit is now created before the read starts. A
valid permit is now available during all stages of the read, enabling
tracking the memory consumption of e.g. the memtable and cache readers.
This change aligns nicely with the needs of more accurate reader memory
tracking, which also wants a valid permit that is available in every layer.
The series can be divided roughly into the following distinct patch
groups:
* 01-02: Give system read concurrency a boost during startup.
* 03-06: Introduce user/system statement isolation to messaging service.
* 07-13: Various infrastructure changes to prepare for using read
permits in all stages of reads.
* 14-19: Propagate the semaphore and the permit from database to the
various table methods that currently create the permit.
* 20-23: Migrate away from using the reader concurrency semaphore for
waiting for admission, use the permit instead.
* 24: Introduce `database::make_query_config()` and switch the database
methods needing such a config to use it.
* 25-31: Get rid of all uses of `no_reader_permit()`.
* 32-33: Ban empty permits for good.
* 34: querier_cache: use the queriers' permits to obtain the semaphore.
Fixes: #5919
Tests: unit(dev, release, debug),
dtest(bootstrap_test.py:TestBootstrap.start_stop_test_node), manual
testing with a 2 node mixed cluster with extra logging.
"
* 'query-class/v6' of https://github.com/denesb/scylla: (34 commits)
querier_cache: get semaphore from querier
reader_permit: forbid empty permits
reader_permit: fix reader_resources::operator bool
treewide: remove all uses of no_reader_permit()
database: make_multishard_streaming_reader: pass valid permit to multi range reader
sstables: pass valid permits to all internal reads
compaction: pass a valid permit to sstable reads
database: add compaction read concurrency semaphore
view: use valid permits for reads from the base table
database: use valid permit for counter read-before-write
database: introduce make_query_class_config()
reader_concurrency_semaphore: remove wait_admission and consume_resources()
test: move away from reader_concurrency_semaphore::wait_admission()
reader_permit: resource_units: introduce add()
mutation_reader: restricted_reader: work in terms of reader_permit
row_cache: pass a valid permit to underlying read
memtable: pass a valid permit to the delegate reader
table: require a valid permit to be passed to most read methods
multishard_mutation_query: pass a valid permit to shard mutation sources
querier: add reader_permit parameter and forward it to the mutation_source
...
GC writer, used for incremental compaction, cannot be currently used if interposer
consumer is used. That's because compaction assumes that GC writer will be operated
only by a single compaction writer at a given point in time.
With interposer consumer, multiple writers will concurrently operate on the same
GC writer, leading to race condition which potentially result in use-after-free.
Let's disable GC writer if interposer consumer is enabled. We're not losing anything
because GC writer is currently only needed on strategies which don't implement an
interposer consumer. Resharding will always disable GC writer, which is the expected
behavior because it doesn't support incremental compaction yet.
The proper fix, which allows GC writer and interposer consumer to work together,
will require more time to implement and test, and for that reason, I am postponing
it as #6472 is a showstopper for the current release.
Fixes#6472.
tests: mode(dev).
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Reviewed-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <20200526195428.230472-1-raphaelsc@scylladb.com>
And use it to obtain any query-class specific configuration that was
obtained from `table::config` before, such as the read concurrency
semaphore and the max memory limit for unlimited queries. As all users
of these items get these from the query class config now, we can remove
them from `table::config`.
