Rename the old version to `sstables::make_reader_v1()`, to have a
nicely searcheable eradication target.
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
gcc 10.3.1 spews the following error:
```
_test_generator::generate_scenario(std::mt19937&) const’:
test/boost/mutation_reader_test.cc:3731:28: error: comparison of integer expressions of different signedness: ‘int’ and ‘long unsigned int’ [-Werror=sign-compare]
3731 | for (auto i = 0; i < num_ranges; ++i) {
| ~~^~~~~~~~~~~~
```
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20210728073538.2467040-1-bhalevy@scylladb.com>
Soon we will switch to up-front admission which will break these tests.
No point in trying to fix them as once the switch is done we'll retire
the restricted reader too. Remove these tests now so they are not in the
way of progress.
As a preparation for up-front admission, add a permit parameter to
`make_multishard_streaming_reader()`, which will be the admitted permit
once we switch to up-front admission. For now it has to be a
non-admitted permit.
A nice side-effect of this patch is that now permits will have a
use-case specific description, instead of the generic
"multishard-streaming-reader" one
This warning prevents using std::move() where it can hurt
- on an unnamed temporary or a named automatic variable being
returned from a function. In both cases the value could be
constructed directly in its final destination, but std::move()
prevents it.
Fix the handful of cases (all trivial), and enable the warning.
Closes#8992
The factory method doesn't match the signature of
`reader_lifecycle_policy::make_reader()`, notably the permit is missing.
Add it as it is important that the wrapping evictable reader and
underlying reader share the permits.
Permits were designed such that there is one permit per read, being
shared by all readers in that read. Make sure readers created by tests
adhere to this.
When recreating the underlying reader, the evictable reader validates
that the first partition key it emits is what it expects to be. If the
read stopped at the end of a partition, it expects the first partition
to be a larger one. If the read stopped in the middle of a certain
partition it expects the first partition to be the same it stopped in
the middle of. This latter assumption doesn't hold in all circumstances
however. Namely, the partition it stopped in the middle of might get
compacted away in the time the read was paused, in which case the read
will resume from a greater partition. This perfectly valid cases however
currently triggers the evictable reader's self validation, leading to
the abortion of the read and a scary error to be logged. Relax this
check to accept any partition that is >= compared to the one the read
stopped in the middle of.
"
This series prevents broken_promise or dangling reader errors
when (resharding) compaction is stopped, e.g. during shutdown.
At the moment compaction just closes the reader unilaterally
and this yanks the reader from under the queue_reader_handle feet,
causing dangling queue reader and broken_promise errors
as seen in #8755.
Instead, fix queue_reader::close to set value on the
_full/_not_full promises and detach from the handle,
and return _consume_fut from bucket_writer::consume
if handle is terminated.
Fixes#8755
Test: unit(dev)
DTest: materialized_views_test.py:TestMaterializedViews.interrupt_build_process_and_resharding_half_to_max_test(debug)
"
* tag 'propagate-reader-abort-v3' of github.com:bhalevy/scylla:
mutation_writer: bucket_writer: consume: propagate _consume_fut if queue_reader_handle is_terminated
queue_reader_handle: add get_exception method
queue_reader: close: set value on promises on detach from handle
To prevent broken_promise exception.
Since close() is manadatory the queue_reader destructor,
that just detaches the reader from the handle, is not
needed anymore, so remove it.
Adjust the test_queue_reader unit test accordingly.
Test: test_queue_reader(dev)
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
The lifecycle of the reader lifecycle policy and all the resources the
reads use is now enclosed in that of the multishard reader thanks to its
close() method. We can now remove all the workarounds we had in place to
keep different resources as long as background reader cleanup finishes.
The purpose of the class in question is to start sharded storage
service to make its global instance alive. I don't know when exactly
it happened but no code that instantiates this wrapper really needs
the global storage service.
Ref: #2795
tests: unit(dev), perf_sstable(dev)
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Message-Id: <20210526170454.15795-1-xemul@scylladb.com>
Currently `with_cql_test_env()` is equivalent to
`with_cql_test_env_thread()`, which resulted in many tests using the
former while really needing the latter and getting away with it. This
equivalence is incidental and will go away soon, so make sure all cql
test env using tests that expect to be run in a thread use the
appropriate variant.
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20210514141614.128213-1-bdenes@scylladb.com>
The mutation_reader_test is already one of our largest test files.
Move the reader concurrency semaphore related tests to a new file,
making them easier to find making the mutation reader test a little bit
smaller too.
These two tests (restricted_reader_timeout and
restricted_reader_max_queue_length) are testing the semaphore in
reality, but through the restricted reader, which is distracting as it
needlessly brings in an additional layer into the picture. Rewrite them
to test the semaphore directly, getting much lighter in the process.
This unit test checks that the semaphore doesn't get into a deadlock
when contended, in the presence of many memory-only reads (that don't
wait for admission). This is tested by simulating the 3 kind of reads we
currently have in the system:
* memory-only: reads that don't pass admission and only own memory.
* admitted: reads that pass admission.
* evictable: admitted reads that are furthermore evictable.
The test creates and runs a large number of these reads in parallel,
read kinds being selected randomly, then creates a watchdog which
kills the test if no progress is being made.
This unit test passes a read through admission again-and-again, just
like an evictable reader would be during its lifetime. When readmitted
the read sometimes has to wait and sometimes not. This is to check that
the readmitting a previously admitted reader doesn't leak any units.
fa43d7680 recently introduced mandatory closing of readers before they
are destroyed. One reader destroy path that was left not closing the
reader before destruction is `inactive_reader_handle::abandon()`. This
path is executed when the handle is destroyed while still referring to a
non-evicted inactive read. This patch fixes it up to close the reader
and adds a small unit test which checks that this happens.
Make flat_mutation_reader::impl::close pure virtual
so that all implementations are required to implemnt it.
With that, provide a trivial implementation to
all implementations that currently use the default,
trivial close implementation.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
In addition to clear_inactive_reads, that's currently called when
the database object is destroyed, introduce a stop() method that will:
1. wait on all background closes of inactive_reads.
2. close all present inactive_reads and waits on their close.
3. signal waiters on the wait_list via broken() with a proper
exception indicating that the semaphore was closed.
In addition, assert in the semaphore's destructor
that it has no remaining inactive reads.
Stop must be called from whoever owns the r_c_s.
Mainly, from database::stop.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Move the logic in ~foreign_reader to close()
to wait on the read_ahead future and close the underlying
reader on the remote shard. Still call close in the background
in ~foreign_reader if destroyed without closing to keep the current
behavior, but warn about it, until it's proved to be unneeded.
Also, added on_iternal_error in close if _read_ahead_future
is engaged but _reader is not, since this must never happen
and we wait on the _read_ahead_future without the _reader.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
When a particular partition exists in at least one sstable, the cache
expects any single-partition query to this partition to return a `partition_start`
fragment, even if the result is empty.
In `time_series_sstable_set::create_single_key_sstable_reader` it could
happen that all sstables containing data for the given query get
filtered out and only sstables without the relevant partition are left,
resulting in a reader which immediately returns end-of-stream (while it
should return a `partition_start` and if not in forwarding mode, a
`partition_end`). This commit fixes that.
We do it by extending the reader queue (used by the clustering reader
merger) with a `dummy_reader` which will be returned by the queue as
the very first reader. This reader only emits a `partition_start` and,
if not in forwarding mode, a `partition_end` fragment.
Fixes#8447.
Closes#8448
The merger could return end-of-stream if some (but not all) of the
underlying readers were empty (i.e. not even returning a
`partition_start`). This could happen in places where it was used
(`time_series_sstable_set::create_single_key_sstable_reader`) if we
opened an sstable which did not have the queried partition but passed
all the filters (specifically, the bloom filter returned a false
positive for this sstable).
The commit also extends the random tests for the merger to include empty
readers and adds an explicit test case that catches this bug (in a
limited scope: when we merge a single empty reader).
It also modifies `test_twcs_single_key_reader_filtering` (regression
test for #8432) because the time where the clustering key filter is
invoked changes (some invocations move from the constructor of the
merger to operator()). I checked manually that it still catches the bug
when I reintroduce it.
Fixes#8445.
Closes#8446
Broken by the move to an intrusive container (9cbbf40), which caused
said method to only clear the container but not destroy the inactive
reads contained therein. This patch restores the previous behaviour and
also adds a call the destructor (to ensure inactive reads are cleaned up
under any circumstances), as well as a unit test.
The multishard combining reader currently assumes that all shards have
data for the read range. This however is not always true and in extreme
cases (like reading a single token) it can lead to huge read
amplification. Avoid this by not pushing shards to
`_shard_selection_min_heap` if the first token they are expected to
produce falls outside of the read range. Also change the read ahead
algorithm to select the shards from `_shard_selection_min_heap`, instead
of walking them in shard order. This was wrong in two ways:
* Shards may be ordered differently with respect to the first partition
they will produce; reading ahead on the next shard in shard order
might not bring in data on the next shard the read will continue on.
Shard order is only correct when starting a new range and shards are
iterated over in the order they own tokens according to the sharding
algorithm.
* Shards that may not have data relevant to the read range are also
considered for read ahead.
After this patch, the multishard reader will only read from shards that
have data relevant to the read range, both in the case of normal reads
and also for read-ahead.
Fixes: #8161
Tests: unit(release)
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20210226132536.85438-1-bdenes@scylladb.com>
`_range_override` is used to store the modified range the reader reads
after it has to be recreated (when recreating a reader it's read range
is reduced to account for partitions it already read). When engaged,
this field overrides the `_pr` field as the definitive range the reader
is supposed to be currently reading. Fast forwarding conceptually
overrides the range the reader is currently reading, however currently
it doesn't reset the `_range_override` field. This resulted in
`_range_override` (containing the modified pre-fast-forward range)
incorrectly overriding the fast-forwarded-to range in `_pr` when
validating the first partition produced by the just recreated reader,
resulting in a false-positive validation failure.
Fixes: #8059
Tests: unit(release)
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20210217164744.420100-1-bdenes@scylladb.com>
The off-by-one error would cause
test_multishard_combining_reader_non_strictly_monotonic_positions to fail if
the added range_tombstones filled the buffer exactly to the end.
In such situation, with the old loop condition,
make_fragments_with_non_monotonic_positions would add one range_tombstone too
many to the deque, violating the test assumptions.
The sstable_mutation_reader, like all other mutation readers expects
that the partition-range passed to it is kept alive by its creator
for the duration of its lifetime. However, the single-key constructor
of the sstable reader was more tolerant, as it only extracted the key
from the range, essentially requiring only the key to be kept alive (but
not the containing range). Naturally in time some code come to rely on
it and ended up passing temporary ranges to the reader. This behaviour
will no longer be acceptable as we are about to consolidate the various
sstable reader constructors, uniformly requiring that the range is kept
alive. So this patch fixes up the tests so they work with this stricter
requirement. Only two occurences were found.
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>
`multishard_combining_reader` currently only works under the assumption
that every table uses the same sharder configured using the node's number
of shards. But we could potentially specify a different sharder for a chosen table,
e.g. one that puts everything on shard 0.
Then this assumption will be broken and the reader causes a segfault.
Fixes#7945.
