Seastar is an external library from Scylla's point of view so
we should use the angle bracket #include style. Most of the source
follows this, this patch fixes a few stragglers.
Also fix cases of #include which reached out to seastar's directory
tree directly, via #include "seastar/include/sesatar/..." to
just refer to <seastar/...>.
Closes#10433
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.
The flat_mutation_reader files were conflated and contained multiple
readers, which were not strictly necessary. Splitting optimizes both
iterative compilation times, as touching rarely used readers doesn't
recompile large chunks of codebase. Total compilation times are also
improved, as the size of flat_mutation_reader.hh and
flat_mutation_reader_v2.hh have been reduced and those files are
included by many file in the codebase.
With changes
real 29m14.051s
user 168m39.071s
sys 5m13.443s
Without changes
real 30m36.203s
user 175m43.354s
sys 5m26.376s
Closes#10194
Although its API was long converted to v2, its implementation stayed v1
because the memtable and mutation API were still v1. Now that the
memtable flush returns a v2 reader we can have a second look at
converting this. While the mutation API still uses v1, this can easily
be worked around by using going through `mutation_rebuilder_v2`.
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20220302145945.189607-1-bdenes@scylladb.com>
"
Also convert the foreign_reader used by it in the process.
Tests: unit(dev)
"
* 'multishard-writer-v2/v1' of https://github.com/denesb/scylla:
mutation_writer/multishard_writer: remove now unused v1 factory overloads
test/boost/mutation_writer_test: test the v2 variant of distribute_reader_and_consume_on_shards()
flat_mutation_reader: add v2 variant of make_generating_reader()
mutation_reader: multishard_writer: migrate implementation to v2
mutation_reader: convert foreign_reader to v2
streaming/consumer: convert to v2
mutation_writer/multishard_writer: add v2 variant of distribute_reader_and_consume_on_shards()
Just the factory function itself. The underlying machinery stays v1 for
now. Behind the scenes the v2 variant still invokes the v1 one, with the
necessary conversions.
This allows migrating users to the v2 interface, migrating the machinery
later.
Memtables are a replica-side entity, and so are moved to the
replica module and namespace.
Memtables are also used outside the replica, in two places:
- in some virtual tables; this is also in some way inside the replica,
(virtual readers are installed at the replica level, not the
cooordinator), so I don't consider it a layering violation
- in many sstable unit tests, as a convenient way to create sstables
with known input. This is a layering violation.
We could make memtables their own module, but I think this is wrong.
Memtables are deeply tied into replica memory management, and trying
to make them a low-level primitive (at a lower level than sstables) will
be difficult. Not least because memtables use sstables. Instead, we
should have a memtable-like thing that doesn't support merging and
doesn't have all other funky memtable stuff, and instead replace
the uses of memtables in sstable tests with some kind of
make_flat_mutation_reader_from_unsorted_mutations() that does
the sorting that is the reason for the use of memtables in tests (and
live with the layering violation meanwhile).
Test: unit (dev)
Closes#10120
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
Just a facade using converters behind the scenes. The actual segregator
is not worth migrating to v2 while mutation and the flushing readers
don't have a v2 versions. Still, migrating all users to a v2 API allows
the conversion to happen at a single point where more work is necessary,
instead of scattered around all the users.
We leave the v1 version in place to aid incremental migration to the v2
one.
Since we have multiple writers using this that we don't want to migrate
all at once, we create a v2 version of said classes so we can migrate
them incrementally.
Due to an error in transforming the above routine, readers who have <= a
buffer worth of content are dropped without consuming them.
This is due to the outer consume loop being conditioned on
`is_end_of_stream()`, which will be set for readers that eagerly
pre-fill their buffer and also have no more data then what is in their
buffer.
Change the condition to also check for `is_buffer_empty()` and only drop
the reader if both of these are true.
Fixes: #9594
Tests: unit(mutation_writer_test --repeat=200, dev)
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20211108092923.104504-1-bdenes@scylladb.com>
The current method of segregating partitions doesn't work well for huge
number of small partitions. For especially bad input, it can produce
hundreds or even thousands of buckets. This patch adds a new segregator
specialized for this use-case. This segregator uses a memtable to sort
out-of-order partitions in-memory. When the memtable size reaches the
provided max-memory limit, it is flushed to disk and a new empty one is
created. In-order partitions bypass the sorting altogether and go to the
fast-path bucket.
The new method is not used yet, this will come in the next patch.
Recently we observed an OOM caused by the partition based splitting
writer going crazy, creating 1.7K buckets while scrubbing an especially
broken sstable. To avoid situations like that in the future, this patch
provides a max limit for the number of live buckets. When the number of
buckets reach this number, the largest bucket is closed and replaced by
a bucket. This will end up creating more output sstables during scrub
overall, but now they won't all be written at the same time causing
insane memory pressure and possibly OOM.
Scrub compaction sets this limit to 100, the same limit the TWCS's
timestamp based splitting writer uses (implemented through the
classifier -
time_window_compaction_strategy::max_data_segregation_window_count).
Fixes: #9400
Tests: unit(dev)
Closes#9401
When the queue_reader_handle is terminated it was
either explicitly aborted or the reader was closed prematurely.
In this case _consume_fut should hold the root-cause error
(e.g. when compaction is stopped). Return it instead
of trying to push the mutation fragment.
If no error is returned from _consume_fut, make to sure to
return either the queue_reader_handle error, if available,
or a generic error since the writer.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Put the reader_consumer declaration in flat_mutation_reader.hh
and include it instead of declaring the same `using reader_consumer`
declaration in several places.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20210607075020.31671-1-bhalevy@scylladb.com>
Add a new segregator which segregates a stream, potentially containing
duplicate or even out-of-order partitions, into multiple output streams,
such that each output stream has strictly monotonic partitions.
This segregator will be used by a new scrub compaction mode which is
meant to fix sstables containing duplicate or out-of-order data.
bucket_writer::close waits for the _consumer_fut.
It is called both after consume_end_of_stream()
and after abort().
_consumer_fut is expected to return an exception
on the abort path. Wait for it and drop any exception
so it won't be abandoned as seen in #7904.
With that moved to close() time, consume_end_of_stream
doesn't need to return a future and is made void
all the way in the stack. This is ok since
queue_reader_handle::push_end_of_stream is synchronous too.
Added a unit test that aborts the reader consumer
during `segregate_by_timestamp`, reproducing the
Exceptional future ignored issue without the fix.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Consolidate shard_based_splitting_writer::shard_writer
and timestamp_based_splitting_writer::bucket_writer
common code into mutation_writer::bucket_writer.
This provides a common place to handle consume_end_of_stream()
and abort(), and in particular the handling of the underlying
_conmsumer_fut.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
After 61520a33d6
feed_writers doesn't call consume_end_of_stream
after abort() so no need to test
if (!_handle.is_terminated()) {
and consume_end_of_stream is now called in then_wrapped
rather than `finally` so it's ok if it throws.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
feed_writer() eats exception and transforms it into an end of stream
instead. Downstream validators hate when this happens.
Fixes#7482
Message-Id: <20201216090038.GB3244976@scylladb.com>
Require a schema and an operation name to be given to each permit when
created. The schema is of the table the read is executed against, and
the operation name, which is some name identifying the operation the
permit is part of. Ideally this should be different for each site the
permit is created at, to be able to discern not only different kind of
reads, but different code paths the read took.
As not all read can be associated with one schema, the schema is allowed
to be null.
The name will be used for debugging purposes, both for coredump
debugging and runtime logging of permit-related diagnostics.
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`.
std::out-of-range does not have a default constructor, yet gcc somehow
accepts a no-argument construction. Clang (correctly) doesn't, so add
a parameter.
C++17 introduced try_emplace for maps to replace a pattern:
if(element not in a map) {
map.emplace(...)
}
try_emplace is more efficient and results in a more concise code.
This commit introduces usage of try_emplace when it's appropriate.
Tests: unit(dev)
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <4970091ed770e233884633bf6d46111369e7d2dd.1597327358.git.piotr@scylladb.com>
The seastar api v4 changes the return type of when_all_succeed. This
patch adds discard_result when that is best solution to handle the
change.
This doesn't do the actual update to v4 since there are still a few
issues left to fix in seastar. A patch doing just the update will
follow.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Message-Id: <20200617233150.918110-1-espindola@scylladb.com>
Seastar recently lost support for the experimental Concepts Technical
Specification (TS) and gained support for C++20 concepts. Re-enable
concepts in Scylla by updating our use of concepts to the C++20
standard.
This change:
- peels off uses of the GCC6_CONCEPT macro
- removes inclusions of <seastar/gcc6-concepts.hh>
- replaces function-style concepts (no longer supported) with
equation-style concepts
- semicolons added and removed as needed
- deprecated std::is_pod replaced by recommended replacement
- updates return type constraints to use concepts instead of
type names (either std::same_as or std::convertible_to, with
std::same_as chosen when possible)
No attempt is made to improve the concepts; this is a specification
update only.
Message-Id: <20200531110254.2555854-1-avi@scylladb.com>
rt is moved before rt.tomb.timestamp is retrieved, so there's a
something that looks like use-after-move here (but really isn't).
found it while auditting the code.
[avi: adjusted changelog to note that it's not really a use-after-move]
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
Message-Id: <20200525141047.168968-1-raphaelsc@scylladb.com>
When using interposers, cancelling compactions can leave futures
that are not waited for (resharding, twcs)
The reason is when consume_end_of_stream gets called, it tries to
push end_of_stream into the queue_reader_handle. Because cancelling
a compaction is done through an exception, the queue_reader_handle
is terminated already at this time. Trying to push to it generates
another exception and prevents us from returning the future right
below it.
This patch adds a new method is_terminated() and if we detect
that the queue_reader_handle is already terminated by this point,
we don't try to push. We call it is_terminated() because the check
is to see if the queue_reader_handle has a _reader. The reader is
also set to null on successful destruction.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Reviewed-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20200430175839.8292-1-glauber@scylladb.com>
