On the read path, the compacting reader is applied only to the sstable
reader. This can cause an expired tombstone from an sstable to be purged
from the request before it has a chance to merge with deleted data in
the memtable leading to data resurrection.
Fix this by checking the memtables before deciding to purge tombstones
from the request on the read path. A tombstone will not be purged if a
key exists in any of the table's memtables with a minimum live timestamp
that is lower than the maximum purgeable timestamp.
Fixes#20916
`perf-simple-query` stats before and after this fix :
`build/Dev/scylla perf-simple-query --smp=1 --flush` :
```
// Before this Fix
// ---------------
94941.79 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59393 insns/op, 24029 cycles/op, 0 errors)
97551.14 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59376 insns/op, 23966 cycles/op, 0 errors)
96599.92 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59367 insns/op, 23998 cycles/op, 0 errors)
97774.91 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59370 insns/op, 23968 cycles/op, 0 errors)
97796.13 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59368 insns/op, 23947 cycles/op, 0 errors)
throughput: mean=96932.78 standard-deviation=1215.71 median=97551.14 median-absolute-deviation=842.13 maximum=97796.13 minimum=94941.79
instructions_per_op: mean=59374.78 standard-deviation=10.78 median=59369.59 median-absolute-deviation=6.36 maximum=59393.12 minimum=59367.02
cpu_cycles_per_op: mean=23981.67 standard-deviation=32.29 median=23967.76 median-absolute-deviation=16.33 maximum=24029.38 minimum=23947.19
// After this Fix
// --------------
95313.53 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59392 insns/op, 24058 cycles/op, 0 errors)
97311.48 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59375 insns/op, 24005 cycles/op, 0 errors)
98043.10 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59381 insns/op, 23941 cycles/op, 0 errors)
96750.31 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59396 insns/op, 24025 cycles/op, 0 errors)
93381.21 tps ( 71.1 allocs/op, 0.0 logallocs/op, 14.1 tasks/op, 59390 insns/op, 24097 cycles/op, 0 errors)
throughput: mean=96159.93 standard-deviation=1847.88 median=96750.31 median-absolute-deviation=1151.55 maximum=98043.10 minimum=93381.21
instructions_per_op: mean=59386.60 standard-deviation=8.78 median=59389.55 median-absolute-deviation=6.02 maximum=59396.40 minimum=59374.73
cpu_cycles_per_op: mean=24025.13 standard-deviation=58.39 median=24025.17 median-absolute-deviation=32.67 maximum=24096.66 minimum=23941.22
```
This PR fixes a regression introduced in ce96b472d3 and should be backported to older versions.
Closesscylladb/scylladb#20985
* github.com:scylladb/scylladb:
topology-custom: add test to verify tombstone gc in read path
replica/table: check memtable before discarding tombstone during read
compaction_group: track maximum timestamp across all sstables
When writing to some tables with materialized views, we need to read from the base table first to perform a delete of the old view row. When doing so, the memory used for the read is tracked by the user read concurrency semaphore. When we have a large number of such reads, we may use up all of the semaphore units, causing the following reads to be queued. When we have some user reads coming at the same time, these reads can have very high latency due to the write workload on the base table. We want to avoid this, so that the write workload doesn't have a high impact on the latency of the read workload.
This is fixed in this patch by adding a separate read concurrency semaphore just for view update read-before-writes. With the new semaphore, even if there are many view update read-before-writes, they will be queued on a different semaphore than the user reads, and they won't impact their latency.
The second issue fixed by this patch is the concurrency of the view updates that is currently unlimited. Because of that view updates may take up so much memory that they we may run out of memory.
This is fixed by using the read admission on the view update concurrency semaphore.
This limits the number of concurrent view update reads to
max_count_concurrent_view_update_reads, all other incoming view update reads are
queued using just a small chunk of memory. Without this, the reads would also get
queued after exceeding view_update_reader_concurrency_semaphore_serialize_limit_multiplier, but they would take much more memory while staying in the queue.
The new semaphore has half the capacity of the regular user read concurrency semahpore and is currently used only for user writes - is't used independently of the scheduling group on which we base the read semaphore selection, but we use a different code path for streaming (not database::do_apply) and we shouldn't have view updates in system writes or during compaction.
This patch also adds a test to confirm that the view update workload doesn't impact the read latency, as well as a test which confirms that we do not run out of memory even under heavy view udpate workload.
The issue of view updates causing increased latencies most often occurs in the following scenario:
* we have a medium to high write workload to a table with a materialized view which requires reading from the base table before sending the update to delete the old rows
* we have any read workload
* one replica is slower or is handling more writes due to an imbalance of data distribution
* we write with a cl<ALL, the mentioned replica is replying to write requests slower while new ones keep being sent to it.
* each write performs a read first taking resources from the user read concurrency semaphore, so when enough writes accumulate the reads using the semaphore start getting queued
* the queue is shared by regular reads and view update reads. When there's enough view update reads in the queue, regular reads start getting increased latencies
An sct test (perf-regression-latency-mv-read-concurrency) was prepared to somewhat resemble this scenario:
* the tables were prepared satisfying the conditions above
* we use a medium write workload and a very low read workload
* the imbalance is achieved by writing to just a few (10) partitions - some replicas (and shards) can have twice or more used partitions than others. We also keep writing to a limited (though high) number of rows, to cause overwrites which require reading before sending the view update
* to minimize the test case, we use a cluster of 3 nodes and rf=2, we write with cl=ONE to have background replica writes and read with cl=ALL to wait for the slower replica to respond.
In the test above:
* without the fix, the latency of reads increases over 50s
* with the fix, the latency of reads stays below 20ms
Fixes https://github.com/scylladb/scylladb/issues/8873
Fixes https://github.com/scylladb/scylladb/issues/15805
The patch is not that small and it isn't fixing a regression, so no backports
Closesscylladb/scylladb#20887
* github.com:scylladb/scylladb:
test: add test for high view update concurrency causing bad_allocs
test: add test for high view update concurrency degrading read latency
mv: add a dedicated read concurrency semaphore for view update read before writes
This helper is small enough and it's easier to understand how table
directory name is formatted without it.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Now this helper is not needed in replica code, as all manipulations of
tables' sstables now sit in the sstables/storage.cc.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
It's write-only now, all the places than wanted to know where table's
storage is (well -- "are", there can be several directories) already use
storage_options.
This finishes the work started by 9fe64b5d70.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
When writing to some tables with materialized views, we need to read from the base
table first to perform a delete of the old view row. When doing so, the memory used
for the read is tracked by the user read concurrency semaphore. When we have a large
number of such reads, we may use up all of the semaphore units, causing the following
reads to be queued. When we have some user reads coming at the same time, these reads
can have very high latency due to the write workload on the base table. We want to avoid
this, so that the write workload doesn't have a high impact on the latency of the
read workload.
This is fixed in this patch by adding a separate read concurrency semaphore just for
view update read-before-writes. With the new semaphore, even if there are many view
update read-before-writes, they will be queued on a different semaphore than the user
reads, and they won't impact their latency.
The second issue fixed by this patch is the concurrency of the view updates that is
currently unlimited. Because of that view updates may take up so much memory that
they we may run out of memory.
This is fixed by using the read admission on the view update concurrency semaphore.
This limits the number of concurrent view update reads to
max_count_concurrent_view_update_reads, all other incoming view update reads are
queued using just a small chunk of memory. Without this, the reads would also get
queued after exceeding view_update_reader_concurrency_semaphore_serialize_limit_multiplier,
but they would take much more memory while staying in the queue.
The new semaphore has half the capacity of the regular user read concurrency semahpore
and is currently used only for user writes - is't used independently of the scheduling
group on which we base the read semaphore selection, but we use a different code path
for streaming (not database::do_apply) and we shouldn't have view updates in system
writes or during compaction.
Fixes https://github.com/scylladb/scylladb/issues/8873
Fixes https://github.com/scylladb/scylladb/issues/15805
On the read path, the compacting reader is applied only to the sstable
reader. This can cause an expired tombstone from an sstable to be purged
from the request before it has a chance to merge with deleted data in
the memtable leading to data resurrection.
Fix this by checking the memtables before deciding to purge tombstones
from the request on the read path. A tombstone will not be purged if a
key exists in any of the table's memtables with a minimum live timestamp
that is lower than the maximum purgeable timestamp.
Fixes#20916
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
implement cassandra original schema option memtable_flush_period_in_ms:
Milliseconds before memtables associated with the table are flushed.
there are few things concerning this patch:
* milliseconds look strange and scary for this option. Unlike Cassandra
we use 60000ms (1min) minimum value for this option.
* This is limitation of Cassandra but it is impossible to set this option
for system tables. However sometimes it could be very useful to use
automatic flushing for such a tables: some system tables have small
traffic and as a result prevent tombstone garbage collection.
Fixes#20270Closesscylladb/scylladb#20999
During split prepare phase, there will be more than 1 compaction group with
overlapping token range for a given replica.
Assume tablet 1 has sstable A containing deleted data, and sstable B containing
a tombstone that shadows data in A.
Then split starts:
1) sstable B is split first, and moved from main (unsplit) group to a
split-ready group
2) now compaction runs in split-ready group before sstable A is split
tombstone GC logic today only looks at underlying group, so compaction is step
2 will discard the deleted data in A, since it belongs to another group (the
unsplit one), and so the tombstone can be purged incorrectly.
To fix it, compaction will now work with all uncompacting sstables that belong
to the same replica, since tombstone GC requires all sstables that possibly
contain shadowed data to be available for correct decision to be made.
Fixes#20044.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
The datadir keeps path to directory where local sstables can be. The very same information is now kept in table's storage options (#20542). This set fixes the remaining places that still use table::config::datadir and table::dir() and removes the datadir field.
Closesscylladb/scylladb#20675
* github.com:scylladb/scylladb:
treewide: Remove table::config::datadir
distributed_loader: Print storage options, not datadir
data_dictionary: Add formatter for storage_options
test: Construct table_for_tests with table storage options
test: Generalize pair of make_table_for_tests helpers
tests: Add helper to get snapshot directory from storage options
table: snapshot_exists: Get directory from storage options
table: snapshot_on_all_shards: Get directory from storage options
Until we automatically support rebuild for tablets-enabled
keyspaces, warn the user about them.
The reason this is not an error, is that after
increasing RF in a new datacenter, the current procedure
is to run `nodetool rebuild` on all nodes in that dc
to rebuild the new vnode replicas.
This is not required for tablets, since the additional
replicas are rebuilt automatically as part of ALTER KS.
However, `nodetool rebuild` is also run after local
data loss (e.g. due to corruption and removal of sstables).
In this case, rebuild is not supported for tablets-enabled
keyspaces, as tablet replicas that had lost data may have
already been migrated to other nodes, and rebuilding the
requested node will not know about it.
It is advised to repair all nodes in the datacenter instead.
Refs scylladb/scylladb#17575
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#20375
It's write-only now, all the places than wanted to know where table's
storage is, already use storage_options.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
When purging regular tombstone consult the min_live_timestamp, if available.
This is safe since we don't need to protect dead data from resurrection, as it is already dead.
For shadowable_tombstones, consult the min_memtable_live_row_marker_timestamp,
if available, otherwise fallback to the min_live_timestamp.
If we see in a view table a shadowable tombstone with time T, then in any row where the row marker's timestamp is higher than T the shadowable tombstone is completely ignored and it doesn't hide any data in any column, so the shadowable tombstone can be safely purged without any effect or risk resurrecting any deleted data.
In other words, rows which might cause problems for purging a shadowable tombstone with time T are rows with row markers older or equal T. So to know if a whole sstable can cause problems for shadowable tombstone of time T, we need to check if the sstable's oldest row marker (and not oldest column) is older or equal T. And the same check applies similarly to the memtable.
If both extended timestamp statistics are missing, fallback to the legacy (and inaccurate) min_timestamp.
Fixesscylladb/scylladb#20423Fixesscylladb/scylladb#20424
> [!NOTE]
> no backport needed at this time
> We may consider backport later on after given some soak time in master/enterprise
> since we do see tombstone accumulation in the field under some materialized views workloads
Closesscylladb/scylladb#20446
* github.com:scylladb/scylladb:
cql-pytest: add test_compaction_tombstone_gc
sstable_compaction_test: add mv_tombstone_purge_test
sstable_compaction_test: tombstone_purge_test: test that old deleted data do not inhibit tombstone garbage collection
sstable_compaction_test: tombstone_purge_test: add testlog debugging
sstable_compaction_test: tombstone_purge_test: make_expiring: use next_timestamp
sstable, compaction: add debug logging for extended min timestamp stats
compaction: get_max_purgeable_timestamp: use memtable and sstable extended timestamp stats
compaction: define max_purgeable_fn
tombstone: can_gc_fn: move declaration to compaction_garbage_collector.hh
sstables: scylla_metadata: add ext_timestamp_stats
compaction_group, storage_group, table_state: add extended timestamp stats getters
sstables, memtable: track live timestamps
memtable_encoding_stats_collector: update row_marker: do nothing if missing
Migrate the `system_distributed.view_build_status` table to `system.view_build_status_v2`. The writes to the v2 table are done via raft group0 operations.
The new parameter `view_builder_version` stored in `scylla_local` indicates whether nodes should use the old or the new table.
New clusters use v2. Otherwise, the migration to v2 is initiated by the topology coordinator when the feature is enabled. It reads all the rows from the old table and writes them to the new table, and sets `view_builder_version` to v2. When the change is applied, all view_builder services are updated to write and read from the v2 table.
The old table `system_distributed.view_build_status` is set to read virtually from the new table in order to maintain compatibility.
When removing a node from the cluster, we remove its rows from the table atomically (fixes https://github.com/scylladb/scylladb/issues/11836). Also, during the migration, we remove all invalid rows.
Fixesscylladb/scylladb#15329
dtest https://github.com/scylladb/scylla-dtest/pull/4827Closesscylladb/scylladb#19745
* github.com:scylladb/scylladb:
view: test view_build_status table with node replace
test/pylib: use view_build_status_v2 table in wait_for_view
view_builder: common write view_build_status function
view_builder: improve migration to v2 with intermediate phase
view: delete node rows from view_build_status on node removal
view: sanitize view_build_status during migration
view: make old view_build_status table a virtual table
replica: move streaming_reader_lifecycle_policy to header file
view_builder: test view_build_status_v2
storage_service: add view_build_status to raft snapshot
view_builder: migration to v2
db:system_keyspace: add view_builder_version to scylla_local
view_builder: read view status from v2 table
view_builder: introduce writing status mutations via raft
view_builder: pass group0_client and qp to view_builder
view_builder: extract sys_dist status operations to functions
db:system_keyspace: add view_build_status_v2 table
To return the minimum live timestamp and live row-marker
timestamp across a compaction_group, storage_group, or
table_state.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Added a new parameter `consider_only_existing_data` to major compaction
API endpoints. When enabled, major compaction will:
- Force-flush all tables.
- Force a new active segment in the commit log.
- Compact all existing SSTables and garbage-collect tombstones by only
checking the SSTables being compacted. Memtables, commit logs, and
other SSTables not part of the compaction will not be checked, as they
will only contain newer data that arrived after the compaction
started.
The `consider_only_existing_data` is passed down to the compaction
descriptor's `gc_check_only_compacting_sstables` option to ensure that
only the existing data is considered for garbage collection.
The option is also passed to the `maybe_flush_commitlog` method to make
sure all the tables are flushed and a new active segment is created in
the commit log.
Fixes#19728
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Major compaction flushes all tables as a part of flushing the commitlog.
After forcing new active segments in the commitlog, all the tables are
flushed to enable reclaim of older commitlog segments. The main goal is
to flush the commitlog and flushing all the table is just a dependency.
Rename maybe_flush_all_tables to maybe_flush_commitlog so that it
reflects the actual intent of the major compaction code. Added a new
wrapper method to database::flush_all_tables(),
database::flush_commitlog(), that is now called from
maybe_flush_commitlog.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
To prevent stalls due to large number of tokens.
For example, large cluster with say 70 nodes can have
more than 16K tokens.
Fixes#19757Closesscylladb/scylladb#19758
* github.com:scylladb/scylladb:
abstract_replication_strategy: make get_ranges async
database: get_keyspace_local_ranges: get vnode_effective_replication_map_ptr param
compaction: task_manager_module: open code maybe_get_keyspace_local_ranges
alternator: ttl: token_ranges_owned_by_this_shard: let caller make the ranges_holder
alternator: ttl: can pass const gms::gossiper& to ranges_holder
alternator: ttl: ranges_holder_primary: unconstify _token_ranges member
alternator: ttl: refactor token_ranges_owned_by_this_shard
To prevent stalls due to large number of tokens.
For example, large cluster with say 70 nodes can have
more than 16K tokens.
Fixes#19757
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Prepare for making the function async.
Then, it will need to hold on to the erm while getting
the token_ranges asynchronously.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
It is used only here and can be simplified by
checking if the keyspace replication strategy
is per table by the caller.
Prepare for making get_keyspace_local_ranges async.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
There's parse_table_directory_name() static helper in database.cc code
that is used by methods that parse table tree layout for snapshot.
Export this helper for external usage and rename to fit the format_...
one introduced by previous patch.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The one makes table directory (not full path) out of table name and
uuid. This is to be symmetrical with yet another helper that converts
dirctory name back to table name and uuid (next patch)
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Currently, database::tables_metadata::add_table needs to hold a write
lock before adding a table. So, if we update other classes keeping
track of tables before calling add_table, and the method yields,
table's metadata will be inconsistent.
Set all table-related info in tables_metadata::add_table_helper (called
by add_table) so that the operation is atomic.
Analogically for remove_table.
Fixes: #19833.
Closesscylladb/scylladb#20064
Consider the following:
```
T
0 split prepare starts
1 repair starts
2 split prepare finishes
3 repair adds unsplit sstables
4 repair ends
5 split executes
```
If repair produces sstable after split prepare phase, the replica will not split that sstable later, as prepare phase is considered completed already. That causes split execution to fail as replicas weren't really prepared. This also can be triggered with load-and-stream which shares the same write (consumer) path.
The approach to fix this is the same employed to prevent a race between split and migration. If migration happens during prepare phase, it can happen source misses the split request, but the tablet will still be split on the destination (if needed). Similarly, the repair writer becomes responsible for splitting the data if underlying table is in split mode. That's implemented in replica::table for correctness, so if node crashes, the new sstable missing split is still split before added to the set.
Fixes#19378.
Fixes#19416.
**Please replace this line with justification for the backport/\* labels added to this PR**
Closesscylladb/scylladb#19427
* github.com:scylladb/scylladb:
tablets: Fix race between repair and split
compaction: Allow "offline" sstable to be split
The reconcilable_result is built as it would be constructed for
forward read queries for tables with reversed order.
Mutations constructed for reversed queries are consumed forward.
Drop overloaded reversed functions that reverse read_command and
reconcilable_result directly and keep only those requiring smart
pointers. They are not used any more.
Remove schema reversing in query() and query_mutations() methods.
Instead, a reversed schema shall be passed for reversed queries.
Rename a schema variable from s into query_schema for readability.
Reverse reads have already been with us for a while, thus this back
door option to read entire paritions forward and reversing them after
can be retired.
Consider the following:
T
0 split prepare starts
1 repair starts
2 split prepare finishes
3 repair adds unsplit sstables
4 repair ends
5 split executes
If repair produces sstable after split prepare phase, the replica
will not split that sstable later, as prepare phase is considered
completed already. That causes split execution to fail as replicas
weren't really prepared. This also can be triggered with
load-and-stream which shares the same write (consumer) path.
The approach to fix this is the same employed to prevent a race
between split and migration. If migration happens during prepare
phase, it can happen source misses the split request, but the
tablet will still be split on the destination (if needed).
Similarly, the repair writer becomes responsible for splitting
the data if underlying table is in split mode. That's implemented
in replica::table for correctness, so if node crashes, the new
sstable missing split is still split before added to the set.
Fixes#19378.
Fixes#19416.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
If parent_info argument of compaction_manager::perform_compaction
is std::nullopt, then created compaction executor isn't tracked by task
manager. Currently, all compaction operations should by visible in task
manager.
Modify split methods to keep split executor in task manager. Get rid of
the option to bypass task manager.
Closesscylladb/scylladb#19995
* github.com:scylladb/scylladb:
compaction: replace optional<task_info> with task_info param
compaction: keep split executor in task manager
Commit ad0e6b79 (replica: Remove all_datadir from keyspace config) removed all_datadirs from keyspace config, now it's datadir turn. After this change keyspace no longer references any on-disk directories, only the sstables's storage driver attached to keyspace's tables does.
refs #12707Closesscylladb/scylladb#19866
* github.com:scylladb/scylladb:
replica: Remove keyspace::config::datadir
sstables/storage: Evaluate path for keyspace directory in storage
sstables/storage: Add sstables_manager arg to init_keyspace_storage()
assert() is traditionally disabled in release builds, but not in
scylladb. This hasn't caused problems so far, but the latest abseil
release includes a commit [1] that causes a 1000 insn/op regression when
NDEBUG is not defined.
Clearly, we must move towards a build system where NDEBUG is defined in
release builds. But we can't just define it blindly without vetting
all the assert() calls, as some were written with the expectation that
they are enabled in release mode.
To solve the conundrum, change all assert() calls to a new SCYLLA_ASSERT()
macro in utils/assert.hh. This macro is always defined and is not conditional
on NDEBUG, so we can later (after vetting Seastar) enable NDEBUG in release
mode.
[1] 66ef711d68Closesscylladb/scylladb#20006
compaction_manager::perform_compaction does not create task manager
task for compaction if parent_info is set to std::nullopt. Currently,
we always want to create task manager task for compaction.
Remove optional from task info parameters which start compaction.
Track all compactions with task manager.
It's finally no longer used. Now only sstables storage code "knows" that
keyspace may have its on-disk directory.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
This is in preparation for the following patch that adds abort_source
variable to the sstables_manager.
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
It was added to make integration of storage groups easier, but it's
complicated since it's another source of truth and we could have
problems if it becomes inconsistent with the group map.
Fixes#18506.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
We currently disable tombstone GC for compaction done on the read path of streaming and repair, because those expired tombstones can still prevent data resurrection. With time-based tombstone GC, missing a repair for long enough can cause data resurrection because a tombstone is potentially GC'd before it could be spread to every node by repair. So repair disseminating these expired tombstones helps clusters which missed repair for long enough. It is not a guarantee because compaction could have done the GC itself, but it is better than nothing.
This last resort is getting less important with repair-based tombstone GC. Furthermore, we have seen this cause huge repair amplification in a cluster, where expired tombstones triggered repair replicating otherwise identical rows.
This series makes tombstone GC on the streaming/repair compaction path configurable with a config item. This new config item defaults to `false` (current behaviour), setting it to `true`, will enable tombstone GC.
Fixes: https://github.com/scylladb/scylladb/issues/19015
Not a regression, no backport needed
Closesscylladb/scylladb#19016
* github.com:scylladb/scylladb:
test/topology_custom/test_repair: add test for enable_tombstone_gc_for_streaming_and_repair
replica/table: maybe_compact_for_streaming(): toggle tombstone GC based on the control flag
replica: propagate enable_tombstone_gc_for_streaming_and_repair to maybe_compact_for_streaming()
db/config: introduce enable_tombstone_gc_for_streaming_and_repair
Currently, a pending replica that applies a write on a table that has
materialized views, will build all the view updates as a normal replica,
only to realize at a late point, in db::view::get_view_natural_endpoint(),
that it doesn't have a paired view replica to send the updates to. It will
then either drop the view updates, or send them to a pending view
replica, if such exists.
This work is unnecessary since it may be dropped, and even if there is a
pending view replica to send the updates to, the updates that are built
by the pending replica may be wrong since it may have incomplete
information.
This commit fixes the inefficiency by skipping the view update building
step when applying an update on a pending replica.
The metric total_view_updates_on_wrong_node is added to count the cases
that a view update is determined to be unnecessary.
The test reproduces the scenario of writing to a table and applying
the update on a pending replica, and verifies that the pending replica
doesn't try to build view updates.
Fixesscylladb/scylladb#19152Closesscylladb/scylladb#19488
flat_mutation_reader_v2 was introduced in a pair of commits in 2021:
e3309322c3 "Clone flat_mutation_reader related classes into v2 variants"
08b5773c12 "Adapt flat_mutation_reader_v2 to the new version of the API"
as a replacement for flat_mutation_reader, using range_tombstone_change
instead of range_tombstone to represent represent range tombstones. See
those commits for more information.
The transition was incremental; the last use of the original
flat_mutation_reader was removed in 2022 in commit
026f8cc1e7 "db: Use mutation_partition_v2 in mvcc"
In turn, flat_mutation_reader was introduced in 2017 in commit
748205ca75 "Introduce flat_mutation_reader"
To transition from a mutation_reader that nested rows within
a partition in a separate stream, to a flat reader that streamed
partitions and rows in the same stream.
Here, we reclaim the original name and rename the awkward
flat_mutation_reader_v2 to mutation_reader.
Note that mutation_fragment_v2 remains since we still use the original
for compatibilty, sometimes.
Some notes about the transition:
- files were also renamed. In one case (flat_mutation_reader_test.cc), the
rename target already existed, so we rename to
mutation_reader_another_test.cc.
- a namespace 'mutation_reader' with two definitions existed (in
mutation_reader_fwd.hh). Its contents was folded into the mutation_reader
class. As a result, a few #includes had to be adjusted.
Closesscylladb/scylladb#19356
Normally, the space overhead for TWCS is 1/N, where is number of windows. But during off-strategy, the overhead is 100% because input sstables cannot be released earlier.
Reshaping a TWCS table that takes ~50% of available space can result in system running out of space.
That's fixed by restricting every TWCS off-strategy job to 10% of free space in disk. Tables that aren't big will not be penalized with increased write amplification, as all input (disjoint) sstables can still be compacted in a single round.
Fixes#16514.
Closesscylladb/scylladb#18137
* github.com:scylladb/scylladb:
compaction: Reduce twcs off-strategy space overhead to 10% of free space
compaction: wire storage free space into reshape procedure
sstables: Allow to get free space from underlying storage
replica: don't expose compaction_group to reshape task
compaction_group sits in replica layer and compaction layer is
supposed to talk to it through compaction::table_state only.
Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com>
