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
(cherry picked from commit 76f0d5e35b)
Closes#17694
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
(cherry picked from commit ee9bfb583c)
Closes#14605
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.
After the fix, the evictable reader starts generating some redundant (but expected) range tombstone change fragments since it's now being paused and resumed. For this we need to adjust mutation source tests which were a bit too specific. We modify `flat_mutation_reader_assertions` to squash the redundant `r_t_c`s.
Fixes#13491Closes#14375
* github.com:scylladb/scylladb:
readers: evictable_reader: don't accidentally consume the entire partition
test: flat_mutation_reader_assertions: squash `r_t_c`s with the same position
(cherry picked from commit 586102b42e)
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
(cherry picked from commit 72003dc35c)
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.
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
"
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()
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
One is a reincarnation of the recently removed
test_multishard_combining_reader_non_strictly_monotonic_positions. The
latter was actually targeting the evictable reader but through the
multishard reader, probably for historic reasons (evictable reader was
part of the multishard reader family).
The other one checks that active range tombstones changes are properly
terminated when the partition ends abruptly after recreating the reader.
Before we add a v2 output option to the compactor, we want to get rid of
all the v1 inputs to make it simpler. This means that for a while the
compacting reader will be in a strange place of having a v2 input and a
v1 output. Hopefully, not for long.
Fast forwarding is delegated to the underlying reader and assumes the
it's supported. The only corner case requiring special handling that has
shown up in the tests is producing partition start mutation in the
forwarding case if there are no other fragments.
compacting state keeps track of uncompacted partition start, but doesn't
emit it by default. If end of stream is reached without producing a
mutation fragment, partition start is not emitted. This is invalid
behaviour in the forwarding case, so I've added a public method to
compacting state to force marking partition as non-empty. I don't like
this solution, as it feels like breaking an abstraction, but I didn't
come across a better idea.
Tests: unit(dev, debug, release)
Message-Id: <20220128131021.93743-1-mikolaj.sieluzycki@scylladb.com>
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
Move replica-oriented classes to the replica namespace. The main
classes moved are ::database, ::keyspace, and ::table, but a few
ancillary classes are also moved. There are certainly classes that
should be moved but aren't (like distributed_loader) but we have
to start somewhere.
References are adjusted treewide. In many cases, it is obvious that
a call site should not access the replica (but the data_dictionary
instead), but that is left for separate work.
scylla-gdb.py is adjusted to look for both the new and old names.
The database, keyspace, and table classes represent the replica-only
part of the objects after which they are named. Reading from a table
doesn't give you the full data, just the replica's view, and it is not
consistent since reconciliation is applied on the coordinator.
As a first step in acknowledging this, move the related files to
a replica/ subdirectory.
The gc_grace_seconds is a very fragile and broken design inherited from
Cassandra. Deleted data can be resurrected if cluster wide repair is not
performed within gc_grace_seconds. This design pushes the job of making
the database consistency to the user. In practice, it is very hard to
guarantee repair is performed within gc_grace_seconds all the time. For
example, repair workload has the lowest priority in the system which can
be slowed down by the higher priority workload, so that there is no
guarantee when a repair can finish. A gc_grace_seconds value that is
used to work might not work after data volume grows in a cluster. Users
might want to avoid running repair during a specific period where
latency is the top priority for their business.
To solve this problem, an automatic mechanism to protect data
resurrection is proposed and implemented. The main idea is to remove the
tombstone only after the range that covers the tombstone is repaired.
In this patch, a new table option tombstone_gc is added. The option is
used to configure tombstone gc mode. For example:
1) GC a tombstone after gc_grace_seconds
cqlsh> ALTER TABLE ks.cf WITH tombstone_gc = {'mode':'timeout'} ;
This is the default mode. If no tombstone_gc option is specified by the
user. The old gc_grace_seconds based gc will be used.
2) Never GC a tombstone
cqlsh> ALTER TABLE ks.cf WITH tombstone_gc = {'mode':'disabled'};
3) GC a tombstone immediately
cqlsh> ALTER TABLE ks.cf WITH tombstone_gc = {'mode':'immediate'};
4) GC a tombstone after repair
cqlsh> ALTER TABLE ks.cf WITH tombstone_gc = {'mode':'repair'};
In addition to the 'mode' option, another option 'propagation_delay_in_seconds'
is added. It defines the max time a write could possibly delay before it
eventually arrives at a node.
A new gossip feature TOMBSTONE_GC_OPTIONS is added. The new tombstone_gc
option can only be used after the whole cluster supports the new
feature. A mixed cluster works with no problem.
Tests: compaction_test.py, ninja test
Fixes#3560
[avi: resolve conflicts vs data_dictionary]
