* Fix CorruptFileIT to also take last DV generation into account
We currently only prune old .liv generations. With soft_deletes it's important
to also prune DV generations.
* Fix CorruptionUtils to skip the footer bytes after the checksum is read.
Today we read a broken checksum since we also checksum the 8 footer bytes that include
the checksum algorithm and the footer magic.
Closes#36526
`PageCacheRecycler` is the class that creates and holds pages of arrays
for various uses. `BigArrays` is just one user of these pages. This
commit moves the constants that define the page sizes for the recycler
to be on the recycler class.
* Upgrae plugin to latest and expose udp
* Explicit check for windows
* Rename the properties for the port numbers
* Tasks for pre and pos container actions
Redeprecates the `/_xpack/rollup` endpoints in favor of `/_rollup`.
When we cleanup the rollup in a cluster containing 6.x nodes we need to
use `/_xpack/rollup` instead of `/_rollup` because the 6.x nodes don't
know about `/_rollup`. In those cases we must ignore the deprecation
warnings that the 7.0 node will return for the end point.
Closes#36044
Currently our handshake requests do not include a version. This is
unfortunate as we cannot rely on the stream version since it is not the
sending node's version. Instead it is the minimum compatibility version.
The handshake request is currently empty and we do nothing with it. This
should allow us to add data to the request without breaking backwards
compatibility.
This commit adds the version to the handshake request. Additionally, it
allows "future data" to be added to the request. This allows nodes to craft
a version compatible response. And will properly handle additional data in
future handshake requests. The proper handling of "future data" is useful
as this is the only request where we do not know the other node's version.
Finally, it renames the TcpTransportHandshaker to
TransportHandshaker.
This commit modifies BigArrays to take a circuit breaker name and
the circuit breaking service. The default instance of BigArrays that
is passed around everywhere always uses the request breaker. At the
network level, we want to be using the inflight request breaker. So this
change will allow that.
Additionally, as this change moves away from a single instance of
BigArrays, the class is modified to not be a Releasable anymore.
Releasing big arrays was always dispatching to the PageCacheRecycler,
so this change makes the PageCacheRecycler the class that needs to be
managed and torn-down.
Finally, this commit closes#31435 be making the serialization of
transport messages use the inflight request breaker. With this change,
we no longer push the global BigArrays instnace to the network level.
Added helper methods to ESRestTestCase for checking warnings in mixed and current-version-only clusters.
This is supported by a new VersionSpecificWarningsHandler class with associated unit test.
Closes#36251
1. CCR tests work without any changes
2. `testDanglingIndices` require changes the source code (added TODO).
3. `testIndexDeletionWhenNodeRejoins` because it's using just two
nodes, adding the node to exclusions is needed on restart.
4. `testCorruptTranslogTruncationOfReplica` starts dedicated master
one, because otherwise, the cluster does not form, if nodes are stopped
and one node is started back.
5. `testResolvePath` needs TEST cluster, because all nodes are stopped
at the end of the test and it's not possible to perform checks needed
by SUITE cluster.
6. `SnapshotDisruptionIT`. Without changes, the test fails because Zen2
retries snapshot creation as soon as network partition heals. This
results into the race between creating snapshot and test cleanup logic
(deleting index). Zen1 on the
other hand, also schedules retry, but it takes some time after network
partition heals, so cleanup logic executes latter and test passes. The
check that snapshot is eventually created is added to
the end of the test.
The following updates were made:
- Add a new untyped endpoint `{index}/_explain/{id}`.
- Add deprecation warnings to Rest*Action, plus tests in Rest*ActionTests.
- For each REST yml test, make sure there is one version without types, and another legacy version that retains types (called *_with_types.yml).
- Deprecate relevant methods on the Java HLRC requests/ responses.
- Update documentation (for both the REST API and Java HLRC).
Allow `auto_date_histogram` as a valid parent agg for derivative,
cumulative sum, moving average, moving function and serial
differencing pipeline aggregations.
Since all these aggs share the same requirement (sequentially
ordered parent aggs), this commit also refactors to share
the same validation code so that any newly added aggs won't
be forgotten.
Closes#35578
This change adds a way to provide the content type of the rest serialization
tests when creating random instances. This is used by SearchHitsTests to ensure
that the internal members of the class are created with the same xContentType
and that equals can be used to compare an instances created from an XContent
view.
This allows you to plug the behavior that the LLRC uses to handle
warnings on a per request basis.
We entertained the idea of allowing you to set the warnings behavior to
strict mode on a per request basis but that wouldn't allow the high
level rest client to fail when it sees an unexpected warning.
We also entertained the idea of adding a list of "required warnings" to
the `RequestOptions` but that won't work well with failures that occur
*sometimes* like those we see in mixed clusters.
Adding a list of "allowed warnings" to the `RequestOptions` would work
for mixed clusters but it'd leave many of the assertions in our tests
weaker than we'd like.
This behavior plugging implementation allows us to make a "required
warnings" option when we need it and an "allowed warnings" behavior when
we need it.
I don't think this behavior is going to be commonly used by used outside
of the Elasticsearch build, but I expect they'll be a few commendably
paranoid folks who could use this behavior.
We support rolling upgrades from Zen1 by keeping the master as a Zen1 node
until there are no more Zen1 nodes in the cluster, using the following
principles:
- Zen1 nodes will never vote for Zen2 nodes
- Zen2 nodes will, while not bootstrapped, vote for Zen1 nodes
- Zen2 nodes that were previously part of a mixed cluster will automatically
(and unsafely) bootstrap themselves when the last Zen1 node leaves.
This is related to #35975. It implements a basic restore functionality
for the CcrRepository. When the restore process is kicked off, it
configures the new index as expected for a follower index. This means
that the index has a different uuid, the version is not incremented, and
the Ccr metadata is installed.
When the restore shard method is called, an empty shard is initialized.
In #34474, we added a new assertion to ensure that the
LocalCheckpointTracker is always consistent with Lucene index. However,
we reset LocalCheckpoinTracker in testDedupByPrimaryTerm cause this
assertion to be violated.
This commit removes resetCheckpoint from LocalCheckpointTracker and
rewrites testDedupByPrimaryTerm without resetting the local checkpoint.
Relates #34474
Today the InternalTestClusterTests sometimes set up a cluster with a single
master, start some other ndoes, shut the original master down, and then reset
the cluster. This doesn't really work, because the original master may be
stale. This change avoids shutting down the only master in this situation.
This commit changes the format of the `hits.total` in the search response to be an object with
a `value` and a `relation`. The `value` indicates the number of hits that match the query and the
`relation` indicates whether the number is accurate (in which case the relation is equals to `eq`)
or a lower bound of the total (in which case it is equals to `gte`).
This change also adds a parameter called `rest_total_hits_as_int` that can be used in the
search APIs to opt out from this change (retrieve the total hits as a number in the rest response).
Note that currently all search responses are accurate (`track_total_hits: true`) or they don't contain
`hits.total` (`track_total_hits: true`). We'll add a way to get a lower bound of the total hits in a
follow up (to allow numbers to be passed to `track_total_hits`).
Relates #33028
The shard deletion logic (triggered by IndicesStore), which also leads to index metadata deletion on
non-master-eligible data nodes, currently races against the new cluster state persistence logic
triggered by accepting cluster states. One thread is writing the index metadata while another one is
deleting the index metadata, leading to exceptions and assertions tripping (see below). The solution
proposed by this PR is to move the cluster state persistence of non-master-eligible nodes back to
the cluster applier service, just as it used to be for Zen1. This ensures that the index metadata
deletion logic, which is triggered by the shard deletion logic, runs on the same thread on which we
persist the cluster state.
Closes#35435
- make it easier to add additional testing tasks with the proper configuration and add some where they were missing.
- mute or fix failing tests
- add a check as part of testing conventions to find classes not included in any testing task.
It is important that all shards of a given index have the same
`indexCreatedVersionMajor` to Lucene, or eg. merging those shards is going to
be considered illegal. At the moment, we use the latest Lucene version when
creating a shard, which could cause shards to have different created versions
eg. in case of forced allocation. This commit makes sure to reuse the
appropriate Lucene version in order to avoid such issues.
Closes#33826
Today we configure the soft-deletes field iff soft-deletes enabled.
Although this choice was correct, it prevents an engine with
soft-deletes disabled from opening a Lucene index with soft-deletes.
Moreover, this change should not have any side-effect if a Lucene index
does not have any soft-deletes.
Relates #36141
This commit implements proper metadata recovery for Zen2.
GatewayService is responsible for the recovery. In Zen1 GatewayService
creates an instance of Gateway, that is used to reach out to other cluster
nodes, get their state and calculate the most up-to-date state based on
versions. After that Gateway performs upgrade and archival of
ClusterSettings and closes bad indices. Then recovered state is passed to GatewayService.GatewayRecoveryListener that mixes up current state
and restored state, removes state not recovered block, creates the
routing table and performs re-routing.
In Zen2 we should perform this kind of logic on cluster startup, except
mixing state (because there is nothing to mix) and opening routing table.
This commit refactors out all `ClusterUpdate` functions in a separate class
`ClusterStateUpdaters`, which is used by `Gateway` and `GatewayService`
in case of Zen1, and by `GatewayMetaState` and `GatewayService` in case of
Zen2.
This commit also switches all integration tests that are already using Zen2 from
InMemoryPersistedState to GatewayMetaState.
This test suite can stop all the shared master-eligible nodes, which breaks the
cluster since any non-shared master-eligible nodes are stopped first in the
reset process between tests.
Since this test suite can leave the cluster in this somewhat broken state, it
seems best that it uses a new cluster for each test.
When building a query Lucene distinguishes two cases, queries that require to produce a score and queries that only need to match. We cloned this mechanism in the QueryBuilders in order to be able to produce different queries based on whether they need to produce a score or not. However the only case in es that require this distinction is the BoolQueryBuilder that sets a different minimum_should_match when a `bool` query is built in a filter context..
This behavior doesn't seem right because it makes the matching of `should` clauses different when the score is not required.
Closes#35293
This fixes a failure of InternalTestClusterTests#testBeforeTest which checks
that the cluster is set up the same when starting from the same seed. Trappily,
using ESTestCase#randomIntBetween() is no good, we have to use
InternalTestCluster#random via RandomNumbers#randomIntBetween() instead.
Today, we allow all nodes in an integration test to bootstrap. However this
seems to lead to test failures due to post-election instability. The change
avoids this instability by only bootstrapping a single node in the cluster.
Empty buckets don't need to be added when performing an incremental reduction step, they can be added later in the final reduction step. This will allow us to later remove the max buckets limit when performing non final reduction.
This is a follow-up to #35144. That commit made the underlying
connection opening process in TcpTransport asynchronous. However the
method still blocked on the process being complete before returning.
This commit moves the blocking to the ConnectionManager level. This is
another step towards the top-level TransportService api being async.
This commit removes the `MockTcpTransport` as a transport option for
`ESIntegTestCase`. It is the first step in replacing the usages of
`MockTcpTransport` with `MockNioTransport`.
CompositeBytesReference#slice has two bugs:
- One that makes it fail if the reference is empty and an empty slice is
created, this is #35950 and is fixed by special-casing empty-slices.
- One performance bug that makes it always create a composite slice when
creating a slice that ends on a boundary, this is fixed by computing `limit`
as the index of the sub reference that holds the last element rather than
the next element after the slice.
Closes#35950
This is related to #34405 and a follow-up to #34753. It makes a number
of changes to our current keepalive pings.
The ping interval configuration is moved to the ConnectionProfile.
The server channel now responds to pings. This makes the keepalive
pings bidirectional.
On the client-side, the pings can now be optimized away. What this
means is that if the channel has received a message or sent a message
since the last pinging round, the ping is not sent for this round.
When wiping rollup jobs, if we are in a mixed cluster with < v7.0 nodes
we need to fall back to the deprecated endpoint because we may talk
to a 6.x node.
Today the default for USE_ZEN2 is false and it is overridden in many places. By
defaulting it to true we can be sure that the only places in which Zen2 does
not work are those in which it is explicitly set to false.
This commit removes the dedicated `setSoLinger` method. This simplifies
the `TcpChannel` interface. This method has very little effect as the
SO_LINGER is not set prior to the channels being closed in the abstract
transport test case. We still will set SO_LINGER on the
`MockNioTransport`. However we can do this manually.
Today GatewayMetaState is capable of atomically storing MetaData to
disk. We've also moved fields that are needed to be persisted in Zen2
from ClusterState to ClusterState.MetaData.CoordinationMetaData.
This commit implements PersistedState interface.
version and currentTerm are persisted as a part of Manifest.
GatewayMetaState now implements both ClusterStateApplier and
PersistedState interfaces. We started with two descendants
Zen1GatewayMetaState and Zen2GatewayMetaState, but it turned
out to be not easy to glue it.
GatewayMetaState now constructs previousClusterState (including
MetaData) and previousManifest inside the constructor so that all
PersistedState methods are usable as soon as GatewayMetaState
instance is constructed. Also, loadMetaData is renamed to
getMetaData, because it just returns
previousClusterState.metaData().
Sadly, we don't have access to localNode (obtained from
TransportService in the constructor, so getLastAcceptedState
should be called, after setLocalNode method is invoked.
Currently, when deciding whether to write IndexMetaData to disk,
we're comparing current IndexMetaData version and received
IndexMetaData version. This is not safe in Zen2 if the term has changed.
So updateClusterState now accepts incremental write
method parameter. When it's set to false, we always write
IndexMetaData to disk.
Things that are not covered by GatewayMetaStateTests are covered
by GatewayMetaStatePersistedStateTests.
This commit also adds an option to use GatewayMetaState instead of
InMemoryPersistedState in TestZenDiscovery. However, by default
InMemoryPersistedState is used and only one test in PersistedStateIT
used GatewayMetaState. In order to use it for other tests, proper
state recovery should be implemented.
Today we have a way to atomically persist global MetaData and
IndexMetaData to disk when new ClusterState is received. All other
ClusterState fields are not persisted.
However, there are other parts of ClusterState that should be
persisted, namely:
version
term
lastCommittedConfiguration
lastAcceptedConfiguration
votingTombstones
version is changed frequently, other fields are not. We decided
to group term, lastCommittedConfiguration,
lastAcceptedConfiguration and votingTombstones into
CoordinationMetaData class and make CoordinationMetaData a field
inside MetaData.
MetaData.toXContent and MetaData.fromXContent should take care of
CoordinationMetaData.
version stays as a top level field in ClusterState and will be
persisted as part of Manifest in a follow-up commit.
Also MetaData.isGlobalStateEquals should be extended to include
coordinationMetaData in comparison.
This commit favors exposing getters, such as getTerm directly in
ClusterState to avoid massive code changes.
An example of CoordinationMetaState.toXContent:
{
"term": 1,
"last_committed_config": [
"TiIuBcbBtpuXyDDVHXeD",
"ZIAoVbkjjLPLUuYLaTkw"
],
"last_accepted_config": [
"OwkXbXZNOZPJqccdFHdz",
"LouzsGYwmQzpeQMrboZe",
"fCKGRZdjLTqzXAqPUtGL",
"pLoxshjpJXwDhbgjfYJy",
"SjINLwFIlIEFZCbjrSFo",
"MDkVncJEVyZLJktopWje"
]
}
- Moves disruption tests to Zen2
- Registers a few missing settings
- Removes .put(TestZenDiscovery.USE_ZEN2.getKey(), true) from tests where Zen2 is now enabled
by default through the parent test class
- Moves QuorumGatewayIT back to Zen1, as it is not stable with Zen2 as it currently relies on
dangling indices due to the lack of proper CS persistence, which triggers secondary failures
This commit adds a rest endpoint for freezing and unfreezing an index.
Among other cleanups mainly fixing an issue accessing package private APIs
from a plugin that got caught by integration tests this change also adds
documentation for frozen indices.
Note: frozen indices are marked as `beta` and available as a basic feature.
Relates to #34352
Zen2 is now feature-complete enough to run most ESIntegTestCase tests. The changes in this PR
are as follows:
- ClusterSettingsIT is adapted to not be Zen1 specific anymore (it was using Zen1 settings).
- Some of the integration tests require persistent storage of the cluster state, which is not fully
implemented yet (see #33958). These tests keep running with Zen1 for now but will be switched
over as soon as that is fully implemented.
- Some very few integration tests are not running yet with Zen2 for other reasons, depending on
some of the other open points in #32006.
Removed extending of AbstractComponent and changed logger usage to
explicit declaration. Abstract classes still have logger
declaration using this.getClass() in order to show implementation class
name in its logs.
See #34488
This changes the test to not use a `CountDownlatch`, instead adding an assertion
for the final logging message and waiting until the `MockAppender` has seen it
before proceeding.
Resolves#23739
Today, the bootstrapping of a Zen2 cluster is driven externally, requiring
something else to wait for discovery to converge and then to inject the initial
configuration. This is hard to use in some situations, such as REST tests.
This change introduces the `ClusterBootstrapService` which brings the bootstrap
retry logic within each node and allows it to be controlled via an (unsafe)
node setting.
This pull request replaces some blocks of code that must be run once
and that are currently based on AtomicBoolean by the convient RunOnce
class added in #35489.
Refactors and simplifies the logic around stopping nodes, making sure that for a full cluster restart
onNodeStopped is only called after the nodes are actually all stopped (and in particular not while
starting up some nodes again). This change also ensures that a closed node client is not being used
anymore (which required a small change to a test).
Relates to #35049
This adds a `wait_for_completion` flag which allows the user to block
the Stop API until the task has actually moved to a stopped state,
instead of returning immediately. If the flag is set, a `timeout` parameter
can be specified to determine how long (at max) to block the API
call. If unspecified, the timeout is 30s.
If the timeout is exceeded before the job moves to STOPPED, a
timeout exception is thrown. Note: this is just signifying that the API
call itself timed out. The job will remain in STOPPING and evenutally
flip over to STOPPED in the background.
If the user asks the API to block, we move over the the generic
threadpool so that we don't hold up a networking thread.
If shutting down half or more of the master-eligible nodes, their votes must
first be explicitly withdrawn to ensure that the cluster doesn't lose its
quorum. This works via _voting tombstones_, stored in the cluster state, which
tell the reconfigurator to remove nodes from the voting configuration.
This change introduces voting tombstones to the cluster state, together with
transport APIs for adding and removing them, and makes use of these APIs in
`InternalTestCluster` to support tests which remove at least half of the
master-eligible nodes at once (e.g. shrinking from two master-eligible nodes to
one).
AbstractComponent was deprecated in #35140 and is looking like it will be
removed at some point by #34888. Today all it does is provide a logger. This
change removes the usages of AbstractComponent that live solely in the zen2
feature branch to avoid some future merge pain, and replaces it where necessary
with some directly-created loggers.
The MockTcpTransport is not friendly in regards to memory usage. It must
allocate multiple byte arrays for every message. This improves the
memory situation by failing fast if the message is improperly formatted.
Additionally, it uses reusable big arrays for at least half of the
allocated byte arrays.
This change adds a logger for the query and fetch phases that prints all requests
before their execution at the trace level. This will help debugging cases where an issue
occurs during the execution since only completed queries are logged by the slow logs.
This is related to #34483. It introduces a namespaced setting for
compression that allows users to configure compression on a per remote
cluster basis. The transport.tcp.compress remains as a fallback
setting. If transport.tcp.compress is set to true, then all requests
and responses are compressed. If it is set to false, only requests to
clusters based on the cluster.remote.cluster_name.transport.compress
setting are compressed. However, after this change regardless of any
local settings, responses will be compressed if the request that is
received was compressed.
Enables diff-based publishing, which is an optimization where only the changing parts of the cluster
state are published to the nodes in the cluster, falling back to full cluster state publishing if the
receiver does not have the previous cluster state.
- Introduces a transport API for bootstrapping a Zen2 cluster
- Introduces a transport API for requesting the set of nodes that a
master-eligible node has discovered and for waiting until this comprises the
expected number of nodes.
- Alters ESIntegTestCase to use these APIs when forming a cluster, rather than
injecting the initial configuration directly.
This change adds a `frozen` engine that allows lazily open a directory reader
on a read-only shard. The engine wraps general purpose searchers in a LazyDirectoryReader
that also allows to release and reset the underlying index readers after any and before
secondary search phases.
Relates to #34352
With this change, `Version` no longer carries information about the qualifier,
we still need a way to show the "display version" that does have both
qualifier and snapshot. This is now stored by the build and red from `META-INF`.
This is related to #29023. Additionally at other points we have
discussed a preference for removing the need to unnecessarily block
threads for opening new node connections. This commit lays the groudwork
for this by opening connections asynchronously at the transport level.
We still block, however, this work will make it possible to eventually
remove all blocking on new connections out of the TransportService
and Transport.
Today we allow the user to set the minimum size of a voting configuration. On
reflection we would rather this was simply '3' where possible, and we can use
the retirement API to control the removal of nodes more explicitly.
This change replaces the old reconfigurator setting with a new one,
`cluster.auto_shrink_voting_configuration`, which determines whether
Elasticsearch should automatically remove nodes from the voting configuration
or not.
When the engine is asked for historical operations, we check if some of the requested operations
are not yet refreshed and if so we refresh before returning the operations. The refresh check is
based on capturing the local checkpoint before each refresh and comparing that value to the one
requested when `newChangesSnapshot` was called. If the requested range is above the captured
local checkpoint we issue a refresh.
This can currently cause unneeded extra refreshes if the method is called concurrently which may cause unwanted degradation in indexing performance. This is especially relevant for CCR where we always ask for a range below the global checkpoint. That range is guaranteed to be below the local
checkpoint of the shard and one refresh is enough to serve multiple changes requests.
This commit fixes this by introducing a dedicated mutex to make sure the test for whether a refresh
is needed actually wait for concurrents for concurrent refreshes that were caused by another
change refresh.
Note that this is not a big change in semantics as refreshes are serialized by lucene anyway. I also
opted not to keep the synchronization to the changes snapshot request only even if in theory we
can apply it to all refreshes, not matter where they come from.
Currently we create a new netty event loop group for client connections
and all server profiles. Each new group creates new threads for io
processing. This means 2 * num of processors new threads for each group.
A single group should be able to handle all io processing (for the
transports). This also brings the netty module inline with what we do
for nio.
Additionally, this PR renames the worker threads to be the same for
netty and nio.
* Introduce property to set version qualifier
- VersionProperties.elasticsearch is now a string which can have qualifier
and snapshot too
- The Version class in the build no longer cares about snapshot and
qualifier.
Stop passing `Settings` to `AbstractComponent`'s ctor. This allows us to
stop passing around `Settings` in a *ton* of places. While this change
touches many files, it touches them all in fairly small, mechanical
ways, doing a few things per file:
1. Drop the `super(settings);` line on everything that extends
`AbstractComponent`.
2. Drop the `settings` argument to the ctor if it is no longer used.
3. If the file doesn't use `logger` then drop `extends
AbstractComponent` from it.
4. Clean up all compilation failure caused by the `settings` removal
and drop any now unused `settings` isntances and method arguments.
I've intentionally *not* removed the `settings` argument from a few
files:
1. TransportAction
2. AbstractLifecycleComponent
3. BaseRestHandler
These files don't *need* `settings` either, but this change is large
enough as is.
Relates to #34488
* NETWORKING: MockTransportService Wait for Close
* Make `MockTransportService` wait `30s` for close listeners to run before failing the assertion
* Closes#34990
Today when ESIntegTestCase starts some nodes it writes out the unicast hosts
files each time a node starts its transport service. This does mean that a
number of nodes can start and perform their first pinging round without any
unicast hosts which, if the timing is unlucky and a lot of nodes are all
started at the same time, can lead to a split brain as in #35052.
Prior to #33554 this was unlikely to happen since the MockUncasedHostsProvider
would always have yielded the existing hosts, so the timing would have to have
been implausibly unlucky. Since #33554, however, it's more likely because the
race occurs between the start of the first round of pinging and the writing of
the unicast hosts file. It is realistic that new nodes will be configured with
the existing nodes from startup, so this change reinstates that behaviour.
Closes#35052.
The java yaml test runner supports sending request headers, yet not all clients support headers. This commit makes sure that we enforce adding a skip section with feature "headers" whenever headers are used in a do section as part of a test. That decreases the chance for new tests to break client builds due to the missing skip section.
Closes#34650
Simon Willnauer
Tim Brooks
Alpar Torok
Nik Everett
Mayya Sharipova
markharwood
Andrey Ershov
Julie Tibshirani
Jernej Klancic
Jim Ferenczi
David Turner
Nhat Nguyen
Yannick Welsch
Adrien Grand
Armin Braun
Luca Cavanna
Zachary Tong
Zachary Tong
Jason Tedor
Christophe Bismuth
Andrey Ershov
Christoph Büscher
Gordon Brown
Arthur Gavlyukovskiy
Lee Hinman
Tanguy Leroux
Nick Knize
Boaz Leskes
Colin Goodheart-Smithe
Tal Levy
Igor Motov
Seong-hyun, Oh