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.
When built by clang this dev-mode test takes ~30 minutes to
complete. Let's reduce this time by reducing the scale of
the test if DEVEL is set.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
"
The storage service is called there to get the cached value
of db::system_keyspace::get_local_host_id(). Keeping the value
on database decouples it from storage service and kills one
more global storage service reference.
tests: unit(dev)
"
* 'br-remove-storage-service-from-counters-2' of https://github.com/xemul/scylla:
counters: Drop call to get_local_storage_service and related
counters: Use local id arg in transform_counter_update_to_shards
database: Have local id arg in transform_counter_updates_to_shards()
storage_service: Keep local host id to database
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.
There are two places that call it -- database code itself and
tests. The former already has the local host id, so just pass
one.
The latter are a bit trickier. Currently they use the value from
storage_service created by storage_service_for_tests, but since
this version of service doesn't pass through prepare_to_join()
the local_host_id value there is default-initialized, so just
default-initialize the needed argument in place.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
This abstraction is used to merge the output of multiple readers, each
opened for a single partition query, into a non-decreasing stream
of mutation_fragments.
It is similar to `mutation_reader_merger`,
but an important difference is that the new merger may select new readers
in the middle of a partition after it already returned some fragments
from that partition. It uses the new `position_reader_queue` abstraction
to select new readers. It doesn't support multi-partition (ring range) queries.
The new merger will be later used when reading from sstable sets created
by TimeWindowCompactionStrategy. This strategy creates many sstables
that are mostly disjoint w.r.t the contained clustering keys, so we can
delay opening sstable readers when querying a partition until after we have
processed all mutation fragments with positions before the keys
contained by these sstables.
A microbenchmark was added that compares the existing combining reader
(which uses `mutation_reader_merger` underneath) with a new combining reader
built using the new `clustering_order_reader_merger` and a simple queue of readers
that returns readers from some supplied set. The used set of readers is built from the following
ranges of keys (each range corresponds to a single reader):
`[0, 31]`, `[30, 61]`, `[60, 91]`, `[90, 121]`, `[120, 151]`.
The microbenchmark runs the reader and divides the result by the number of mutation fragments.
The results on my laptop were:
```
$ build/release/test/perf/perf_mutation_readers -t clustering_combined.* -r 10
single run iterations: 0
single run duration: 1.000s
number of runs: 10
test iterations median mad min max
clustering_combined.ranges_generic 2911678 117.598ns 0.685ns 116.175ns 119.482ns
clustering_combined.ranges_specialized 3005618 111.015ns 0.349ns 110.063ns 111.840ns
```
`ranges_generic` denotes the existing combining reader, `ranges_specialized` denotes the new reader.
Split from https://github.com/scylladb/scylla/pull/7437.
Closes#7688
* github.com:scylladb/scylla:
tests: mutation_source_test for clustering_order_reader_merger
perf: microbenchmark for clustering_order_reader_merger
mutation_reader_test: test clustering_order_reader_merger in memory
test: generalize `random_subset` and move to header
mutation_reader: introduce clustering_order_reader_merger
When a row was inserted into a table with no regular columns, and no
such row existed in the first place, postimage would not be produced.
Fix this.
Fixes#7716.
Closes#7723
Previously, statement_restrictions::find_idx() would happily return an
index for a non-EQ restriction (because it checked only the column
name, not the operator). This is incorrect: when the selected index
is for a non-EQ restriction, it is impossible to query that index
table.
Fixes#7659.
Tests: unit (dev)
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
Closes#7665
This abstraction is used to merge the output of multiple readers, each
opened for a single partition query, into a non-decreasing stream
of mutation_fragments.
It is similar to `mutation_reader_merger`,
an important difference is that the new merger may select new readers
in the middle of a partition after it already returned some fragments
from that partition. It uses the new `position_reader_queue` abstraction
to select new readers. It doesn't support multi-partition (ring range) queries.
The new merger will be later used when reading from sstable sets created
by TimeWindowCompactionStrategy. This strategy creates many sstables
that are mostly disjoint w.r.t the contained clustering keys, so we can
delay opening sstable readers when querying a partition until after we have
processed all mutation fragments with positions before the keys
contained by these sstables.
Fix#7680 by never using secondary index for multi-column restrictions.
Modify expr::is_supported_by() to handle multi-column correctly.
Tests: unit (dev)
Closes#7699
* github.com:scylladb/scylla:
cql3/expr: Clarify multi-column doesn't use indexing
cql3: Don't use index for multi-column restrictions
test: Add eventually_require_rows
Reject the previously accepted case where the multi-column restriction
applied to just a single column, as it causes a crash downstream. The
user can drop the parentheses to avoid the rejection.
Fixes#7710
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
Closes#7712
"
This series adds maybe_yield called from
cleanup_compaction::get_ranges_for_invalidation
to avoid reactor stalls.
To achieve that, we first extract bool_class can_yield
to utils/maybe_yield.hh, and add a convience helper:
utils::maybe_yield(can_yield) that conditionally calls
seastar::thread::maybe_yield if it can (when called in a
seastar thread).
With that, we add a can_yield parameter to dht::to_partition_ranges
and dht::partition_range::deoverlap (defaults to false), and
use it from cleanup_compaction::get_ranges_for_invalidation,
as the latter is always called from `consume_in_thread`.
Fixes#7674
Test: unit(dev)
"
* tag 'unstall-get_ranges_for_invalidation-v2' of github.com:bhalevy/scylla:
compaction: cleanup_compaction: get_ranges_for_invalidation: add yield points
dht/i_partitioner: to_partition_ranges: support yielding
locator: extract can_yield to utils/maybe_yield.hh
The downstream code expects a single-column restriction when using an
index. We could fix it, but we'd still have to filter the rows
fetched from the index table, unlike the code that queries the base
table directly. For instance, WHERE (c1,c2,c3) = (1,2,3) with an
index on c3 can fetch just the right rows from the base table but all
the c3=3 rows from the index table.
Fixes#7680
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
After a node becomes leader it needs to do two things: send an append
message to establish its leadership and commit one entry to make sure
all previous entries with smaller terms are committed as well.
Move the definition of bool_class can_yield to a standalone
header file and define there a maybe_yield(can_yield) helper.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
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
Now that CDC is GA, it should be enabled in all the tests by default.
To achieve that the PR adds a special db::config::add_cdc_extension()
helper which is used in cql_test_envm to make sure CDC is usable in
all the tests that use cql_test_env.m As a result, cdc_tests can be
simplified.
Finally, some trailing whitespaces are removed from cdc_tests.
Tests: unit(dev)
Closes#7657
* github.com:scylladb/scylla:
cdc: Remove trailing whitespaces from cdc_tests
cdc: Remove mk_cdc_test_config from tests
config: Add add_cdc_extension function for testing
cdc: Add missing includes to cdc_extension.hh
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 qctx is global object that references query processor and
database to let the rest of the code query system keyspace.
As the first step of de-globalizing it -- remove the database
reference from it. After the set the qctx remains a simple
wrapper over the query processor (which is already de-globalized)
and the query processor in turn is mostly needed only to parse
the query string into prepared statement only. This, in turn,
makes it possible to remove the qctx later by parsing the
query strings on boot and carrying _them_ around, not the qctx
itself.
tests: unit(dev), dtest(simple_cluster_driver_test:dev), manual start/stop
"
* 'br-remove-database-from-qctx' of https://github.com/xemul/scylla:
query-context: Remove database from qctx
schema-tables: Use query processor referece in save_system(_keyspace)?_schema
system-keyspace: Rewrite force_blocking_flush
system-keyspace: Use cluster_name string in check_health
system-keyspace: Use db::config in setup_version
query-context: Kill global helpers
test: Use cql_test_env::evecute_cql instead of qctx version
code: Use qctx::evecute_cql methods, not global ones
system-keyspace: Do not call minimal_setup for the 2nd time
system-keyspace: Fix indentation after previous patch
system-keyspace: Do not do invoke_on_all by hands
system-keyspace: Remove dead code
Similar to previous patch, but for tests. Since cql_test_env
does't have qctx on board, the patch makes one step forward
and calls what is called by qctx::execute_cql.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Now that CDC is GA and enabled by default, there's no longer a need
for a specific config in CDC tests.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
"
We've recently seen failures in this unit test as follows:
```
test/boost/network_topology_strategy_test.cc(0): Entering test case "testCalculateEndpoints"
unknown location(0): fatal error: in "testCalculateEndpoints": std::out_of_range: _Map_base::at
./seastar/src/testing/seastar_test.cc(43): last checkpoint
test/boost/network_topology_strategy_test.cc(0): Leaving test case "testCalculateEndpoints"; testing time: 15192us
test/boost/network_topology_strategy_test.cc(0): Entering test case "test_invalid_dcs"
network_topology_strategy_test: ./seastar/include/seastar/core/future.hh:634: void seastar::future_state<seastar::internal::monostate>::set(A &&...) [T = seastar::internal::monostate, A = <>]: Assertion `_u.st == state::future' failed.
Aborting on shard 0.
```
This series fixes 2 issues in this test:
1. The core issue where std::out_of_range exception
is not handled in calculate_natural_endpoints().
2. A secondary issue where the static `snitch_inst` isn't
stopped when the first exception is hit, failing
the next time the snitch is started, as it wasn't
stopped properly.
Test: network_topology_strategy_test(release)
"
* tag 'nts_test-harden-calculate_natural_endpoints-v1' of github.com:bhalevy/scylla:
test: network_topology_strategy_test: has_sufficient_replicas: handle empty dc endpoints case
test: network_topology_strategy_test: fixup indentation
test: network_topology_strategy_test: always stop_snitch after create_snitch
We saw this intermittent failure in testCalculateEndpoints:
```
unknown location(0): fatal error: in "testCalculateEndpoints": std::out_of_range: _Map_base::at
```
It turns out that there are no endpoints associated with the dc passed
to has_sufficient_replicas in the `all_endpoints` map.
Handle this case by returning true.
The dc is still required to appear in `dc_replicas`,
so if it's not found there, fail the test gracefully.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Currently stop_snitch is not called if the test fails on exception.
This causes a failure in create_snitch where snitch_inst fails to start
since it wasn't stopped earlier.
For example:
```
test/boost/network_topology_strategy_test.cc(0): Entering test case "testCalculateEndpoints"
unknown location(0): fatal error: in "testCalculateEndpoints": std::out_of_range: _Map_base::at
./seastar/src/testing/seastar_test.cc(43): last checkpoint
test/boost/network_topology_strategy_test.cc(0): Leaving test case "testCalculateEndpoints"; testing time: 15192us
test/boost/network_topology_strategy_test.cc(0): Entering test case "test_invalid_dcs"
network_topology_strategy_test: ./seastar/include/seastar/core/future.hh:634: void seastar::future_state<seastar::internal::monostate>::set(A &&...) [T = seastar::internal::monostate, A = <>]: Assertion `_u.st == state::future' failed.
Aborting on shard 0.
Backtrace:
0x0000000002825e94
0x000000000282ffa9
0x00007fd065f971df
/lib64/libc.so.6+0x000000000003dbc4
/lib64/libc.so.6+0x00000000000268a3
/lib64/libc.so.6+0x0000000000026788
/lib64/libc.so.6+0x0000000000035fc5
0x0000000000b484cf
0x0000000002a7c69f
0x0000000002a7c62f
0x0000000000b47b9e
0x0000000002595da2
0x0000000002595913
0x0000000002a83a31
```
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
scoped_critical_alloc_section was recently introduced to replace
disable_failure_guard and made the old class deprecated.
This patch replaces all occurences of disable_failure_guard with
scoped_critical_alloc_section.
Without this patch the build prints many warnings like:
warning: 'disable_failure_guard' is deprecated: Use scoped_critical_section instead [-Wdeprecated-declarations]
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
Message-Id: <ca2a91aaf48b0f6ed762a6aa687e6ac5e936355d.1605621284.git.piotr@scylladb.com>
As requested in #7057, allow certain alterations of system_auth tables. Potentially destructive alterations are still rejected.
Tests: unit (dev)
Closes#7606
* github.com:scylladb/scylla:
auth: Permit ALTER options on system_auth tables
auth: Add command_desc
auth: Add tests for resource protections
These alterations cannot break the database irreparably, so allow
them.
Expand command_desc as required.
Add a type (rather than command_desc) parameter to
has_column_family_access() to minimize code changes.
Fixes#7057
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
Add new alternator-streams experimental flag for
alternator streams control.
CDC becomes GA and won't be guarded by an experimental flag any more.
Alternator Streams stay experimental so now they need to be controlled
by their own experimental flag.
Signed-off-by: Piotr Jastrzebski <piotr@scylladb.com>
"
This series is a rebased version of 3 patchsets that were sent
separately before:
1. [PATCH v4 00/17] Cleanup storage_service::update_pending_ranges et al.
This patchset cleansup service/storage_service use of
update_pending_ranges and replicate_to_all_cores.
It also moves some functionality from gossiping_property_file_snitch::reload_configuration
into a new method - storage_service::update_topology.
This prepares storage_service for using a shared ptr to token_metadata,
updating a copy out of line under a semaphore that serializes writers,
and eventually replicating to updated copy to all shards and releasing
the lock. This is a follow up to #7044.
2. [PATCH v8 00/20] token_metadata versioned shared ptr
Rather than keeping references on token_metadata use a shared_token_metadata
containing a lw_shared_ptr<token_metadata> (a.k.a token_metadata_ptr)
to keep track of the token_metadata.
Get token_metadata_ptr for a read-only snapshot of the token_metadata
or clone one for a mutable snapshot that is later used to safely update
the base versioned_shared_object.
token_metadata_ptr is used to modify token_metadata out of line, possibly with
multiple calls, that could be preeempted in-between so that readers can keep a consistent
snapshot of it while writers prepare an updated version.
Introduce a token_metadata_lock used to serialize mutators of token_metadata_ptr.
It's taken by the storage_service before cloning token_metadata_ptr and held
until the updated copy is replicated on all shards.
In addition, this series introduces token_metadata::clone_async() method
to copy the tokne_metadata class using a asynchronous function with
continuations to avoid reactor stalls as seen in #7220.
Fixes#7044
3. [PATCH v3 00/17] Avoid stalls in token_metadata and replication strategy
This series uses the shared_token_metadata infrastructure.
First patches in the series deal wth cloning token_metadata
using continuations to allow preemption while cloning (See #7220).
Then, the rest of the series makes sure to always run
`update_pending_ranges` and `calculate_pending_ranges_for_*` in a thread,
it then adds a `can_yield` parameter to the token_metadata and abstract_replication_strategy
`get_pending_ranges` and friends, and finally it adds `maybe_yield` calls
in potentially long loops.
Fixes#7313Fixes#7220
Test: unit (dev)
Dtest: gating(dev)
"
* tag 'replication_strategy_can_yield-v4' of github.com:bhalevy/scylla: (54 commits)
token_metadata_impl: set_pending_ranges: add can_yield_param
abstract_replication_strategy: get rid of get_ranges_in_thread
repair: call get_ranges_in_thread where possible
abstract_replication_strategy: add can_yield param to get_pending_ranges and friends
abstract_replication_strategy: define can_yield bool_class
token_metadata_impl: calculate_pending_ranges_for_* reindent
token_metadata_impl: calculate_pending_ranges_for_* pass new_pending_ranges by ref
token_metadata_impl: calculate_pending_ranges_for_* call in thread
token_metadata: update_pending_ranges: create seastar thread
abstract_replication_strategy: add get_address_ranges method for specific endpoint
token_metadata_impl: clone_after_all_left: sort tokens only once
token_metadata: futurize clone_after_all_left
token_metadata: futurize clone_only_token_map
token_metadata: use mutable_token_metadata_ptr in calculate_pending_ranges_for_*
repair: replace_with_repair: use token_metadata::clone_async
storage_service: reindent token_metadata blocks
token_metadata: add clone_async
abstract_replication_strategy: accept a token_metadata_ptr in get_pending_address_ranges methods
abstract_replication_strategy: accept a token_metadata_ptr in get_ranges methods
boot_strapper: get_*_tokens: use token_metadata_ptr
...
To facilitate that, keep a const shared_token_metadata& in class database
rather than a const token_metadata&
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
In preparation to chaging network_topology_strategy to
accept a const shared_token_metadata& rather than token_metadata&.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
And use it to get a token_metadata& compatible
with current usage, until the services are converted to
use token_metadata_ptr.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
If the consumer happens to check the EOS flag before it hits the
exception injected by the abort (by calling fill_buffer()), they can
think the stream ended normally and expect it to be valid. However this
is not guaranteed when the reader is aborted. To avoid consumers falsely
thinking the stream ended normally, don't set the EOS flag on abort at
all.
Additionally make sure the producer is aborted too on abort. In theory
this is not needed as they are the one initiating the abort, but better
to be safe then sorry.
Fixes: #7411
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20201102100732.35132-1-bdenes@scylladb.com>
"
Today, if scylla crashes mid-way in sstable::idempotent-move-sstable
or sstable::create_links we may end up in an inconsistent state
where it refuses to restart due to the presence of the moved-
sstable component files in both the staging directory and
main directory.
This series hardens scylla against this scenario by:
1. Improving sstable::create_links to identify the replay condition
and support it.
2. Modifying the algorithm for moving sstables between directories
to never be in a state where we have two valid sstable with the
same generation, in both the source and destination directories.
Instead, it uses the temporary TOC file as a marker for rolling
backwards or forewards, and renames it atomically from the
destination directory back to the source directory as a commit
point. Before which it is preparing the sstable in the destination
dir, and after which it starts the process of deleting the sstable
in the source dir.
Fixes#7429
Refs #5714
"
* tag 'idempotent-move-sstable-v3' of github.com:bhalevy/scylla:
sstable: create_links: support for move
sstable_directory: support sstables with both TemporaryTOC and TOC
sstable: create_links: move automatic sstring variables
sstable: create_links: use captured comps
sstable: create_links: capture dir by reference
sstable: create_links: fix indentation
sstable: create_links: no need to roll-back on failure anymore
sstable: create_links: support idempotent replay
sstable: create_links: cleanup style
sstable: create_links: add debug/trace logging
sstable: move_to_new_dir: rm TOC last
sstable: move_to_new_dir: io check remove calls
test: add sstable_move_test
I noticed that we require filtering for continuous clustering key, which is not necessary. I dropped the requirement and made sure the correct data is read from the storage proxy.
The corresponding dtest PR: https://github.com/scylladb/scylla-dtest/pull/1727
Tests: unit (dev,debug), dtest (next-gating, cql*py)
Closes#7460
* github.com:scylladb/scylla:
cql3: Delete some newlines
cql3: Drop superfluous ALLOW FILTERING
cql3: Drop unneeded filtering for continuous CK
When moving a sstable between directories, we would like to
be able to crash at any point during the algorithm with a
clear way to either roll the operation forwards or backwards.
To achieve that, define sstable::create_links_common that accepts
a `mark_for_removal` flag, implementing the following algorithm:
1. link src.toc to dst.temp_toc.
until removed, the destination sstable is marked for removal.
2. link all src components to dst.
crashing here will leave dst with both temp_toc and toc.
3.
a. if mark_for_removal is unset then just remove dst.temp_toc.
this is commit the destination sstable and complete create_links.
b. if mark_for_removal is set then move dst.temp_toc to src.temp_toc.
this will atomically toggle recovery after crash from roll-back
to roll-forward.
here too, crashing at this point will leave src with both
temp_toc and toc.
Adjust the unit test for the revised algorithm.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Keep descriptors in a map so it could be searched easily by generation.
and possibly delete the descriptor, if found, in the presence of
a temporary toc component.
A following patch will add support to create_links for moving
sstables between directories. It is based on keeping a TemporaryTOC
file in the destination directory while linking all source components.
If scylla crashes here, the destination sstable will have both
its TemporaryTOC and TOC components and it needs to be removed
to roll the move backwards.
Then, create_links will atomically move the TemporaryTOC from
the destination back to the source directory, to toggle rolling
back to rolling forward by marking the source sstable for removal.
If scylla crashes here, the source sstable will have both
its TemporaryTOC and TOC components and it needs to be removed
to roll the move forward.
Add unit test for this case.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Handle the case where create_link is replayed after crashing in the middle.
In particular, if we restart when moving sstables from staging to the base dir,
right after create_links completes, and right before deleting the source links,
we end up with seemingly 2 valid sstables, one still in staging and the other
already in the base table directory, both are hard linked to the same inodes.
Make create_links idempotent so it can replay the operation safely if crashed and
restarted at any point of its operation.
Add unit tests for replay after partial create_links that is expected to succeed,
and a test for replay when an sstable exist in the destination that is not
hard-linked to the source sstable; create_links is expected to fail in this case.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
