The issue is that FileInputStream is created with try-with-resources, so its close() is called right after the try sentence.
FileInputStream is a finalize class, when this object is garbage collected, its close() is called again.
To avoid this double-free resources, add guard against it.
Signed-off-by: stack <stack@apache.org>
Don't have every handler update regionserver metrics on each
scan#nextRaw; instead, do a batch update just before Scan
returns. Otherwise, all running handlers end up contending
on metrics update.
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
Update of regionserver metrics counters moved out to caller where
can be done as a batch update instead of per-next.
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionServer.java
Class doc to encourage batch updating metrics.
Remove the single update as unused anymore.
M hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RSRpcServices.java
Count calls to nextRaw. Update regionserver count in finally block when
scan is done rather than per nextRaw call. Move all metrics updates to
finally.
Signed-off-by: Reid Chan <reidchan@apache.org>
Signed-off-by: Baiqiang Zhao <ZhaoBQ>
Introduces a new metric that tracks number of replication sources that are stuck in initialization.
Signed-off-by: Xu Cang <xucang@apache.org>
Signed-off-by: Bharath Vissapragada <bharathv@apache.org>
(cherry picked from commit ff3821814a)
Add a toString to all split policy implementations listing name and
vitals. Use this toString in the Region open message. Ditto for flush
policy for the Region.
Signed-off-by: Huaxiang Sun<huaxiangsun@apache.org>
Turn down the amount we log. If you want to see the full exception
enable TRACE-level logging.
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: shahrs87
Close the stream using a try-with-resources block.
Reviewed-by: Aman Poonia <aman.poonia.29@gmail.com>
Signed-off-by: Wei-Chiu Chuang <weichiu@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
Signed-off-by: Bharath Vissapragada <bharathv@apache.org>
(cherry picked from commit 573daed419)
ServerCall.java: calling wrapWithSasl() was moved to getResponse(), so
the SASL wrapping is delayed until the reply is sent back to the client.
Signed-off-by: Peter Somogyi <psomogyi@apache.org>
ProtobufLogReader#readNext may be called by code that attempts to advance
the reader but does not necessarily expect to succeed, for example
WALEntryStream#tryAdvanceEntry. Much of the logging in this method is
at TRACE level. Other logging at WARN level will be frequently emitted, as
often as several per minute, and this will cause false positive assessment
from operators that they are experiencing a bug. Fix the mixed intent with
respect to log levels in readNext. Log at only DEBUG level or below.
Signed-off-by: Sean Busbey <busbey@apache.org>
* HBASE-25542 Add client detail to scan name so when lease expires, we have clue on who was scanning
When we create a scanner lease, record client ip and port (removed
unnecessary store of scannerName).
Signed-off-by: Clara Xiong <clarax98007@gmail.com>
Retain assignment will be useful in non-cloud scenario where RegionServer and Datanode are deployed in same machine and will avoid remote read.
Signed-off-by: Guanghao Zhang <zghao@apache.org>
Signed-off-by: Anoop Sam John <anoopsamjohn@apache.org>
(cherry picked from commit a04ea7ea44)
Adds "hbase.master.executor.merge.dispatch.threads" and defaults to 2.
Also adds additional logging that includes the number of split plans
and merge plans computed for each normalizer run.
(cherry picked from commit 36b4698cea)
Restore removed method overrides for AccessController and VisibilityController,
which are both LimitedPrivate(CONFIG) interfaces and per compatibility
guidelines cannot have methods removed in patch releases.
Signed-off-by: Andrew Purtell <apurtell@apache.org>
Some OMME can not cause the JVM to exit, like "java.lang.OutOfMemoryError: Direct buffer memory", "java.lang.OutOfMemoryError: unable to create new native thread", as they dont call vmError#next_OnError_command. So abort HMaster when uncaught exception occurs in TimeoutExecutor, the new active Hmaster will resume the suspended procedure.
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: stack <stack@apache.com>
Signed-off-by: Pankaj Kumar<pankajkumar@apache.org>
(cherry picked from commit 600be60a4b)
(cherry picked from commit ae77f81e7e)
* Using ContiguousCellFormat as a marker alone
* Commit the new file
* Fix the comparator logic that was an oversight
* Fix the sequenceId check order
* Adding few more static methods that helps in scan flow like query
matcher where we have more cols
* Remove ContiguousCellFormat and ensure compare() can be inlined
* applying negation as per review comment
* Fix checkstyle comments
* fix review comments
* Address review comments
Signed-off-by: stack <stack@apache.org>
Signed-off-by: AnoopSamJohn <anoopsamjohn@apache.org>
Signed-off-by: huaxiangsun <huaxiangsun@apache.org>
* HBASE-25277 postScannerFilterRow impacts Scan performance a lot in HBase 2.x
1. Added a check for Object class in RegionCoprocessorHost to avoid wrong initialization of hasCustomPostScannerFilterRow
2. Removed dummy implementation of postScannerFilterRow from AccessController, VisibilityController & ConstraintProcessor (which are not required currently)
Signed-off-by Ramkrishna S Vasudevan <ramkrishna@apache.org>
Signed-off-by Anoop Sam John <anoopsamjohn@apache.org>
Signed-off-by: Duo Zhang <zhangduo@apache.org>
(cherry picked from commit fb6e498b32)
Add a bit of a wait before testing if online replicas match the zk count. It might take a
while for all replicas to come online.
Signed-off-by: huaxiangsun <huaxiangsun@apache.org>
Check TEST_SKIP_REPORTING_TRANSITION and if true, skip trying to talk to
update master on state transition -- i.e. reportFileArchivalForQuotas --
as we allow for reportRegionStateTransition (For tests only)
Signed-off-by: Huaxiang Sun <huaxiangsun@apache.com>
This PR is a follow-up of HBASE-25181 (#2539), where several issues were
discussed on the PR:
1. Currently we use PBKDF2WithHmacSHA1 key generation algorithm to generate a
secret key for HFile / WalFile encryption, when the user is defining a string
encryption key in the hbase shell. This algorithm is not secure enough and
not allowed in certain environments (e.g. on FIPS compliant clusters). We are
changing it to PBKDF2WithHmacSHA384. It will not break backward-compatibility,
as even the tables created by the shell using the new algorithm will be able
to load (e.g. during bulkload / replication) the HFiles serialized with the
key generated by an old algorithm, as the HFiles themselves already contain
the key necessary for their decryption.
Smaller issues fixed by this commit:
2. Improve the documentation e.g. with the changes introduced by HBASE-25181
and also by some points discussed on the Jira ticket of HBASE-25263.
3. In EncryptionUtil.createEncryptionContext the various encryption config
checks should throw IllegalStateExceptions instead of RuntimeExceptions.
4. Test cases in TestEncryptionTest.java should be broken down into smaller
tests.
5. TestEncryptionDisabled.java should use ExpectedException JUnit rule to
validate exceptions.
closes#2676
Signed-off-by: Peter Somogyi <psomogyi@apache.org>
* HBASE-25050 - We initialize Filesystems more than once.
* Ensuring that calling the FS#get() will only ensure FS init.
* Fix for testfailures. We should pass the entire path and no the scheme
alone
* Cases where we don't have a scheme for the URI
* Address review comments
* Add some comments on why FS#get(URI, conf) is getting used
* Adding the comment as per Sean's review
Signed-off-by: Sean Busbey <busbey@apache.org>
Signed-off-by: Michael Stack <stack@apache.org>
* HBASE-25187 Improve SizeCachedKV variants initialization
* HBASE-25187 Improve SizeCachedKV variants initialization
* The BBKeyValue also can be optimized
* Change for SizeCachedKeyValue
* Addressing revew comments
* Fixing checkstyle and spot bugs comments
* Spot bug fix for hashCode
* Minor updates make the rowLen as short and some consturctor formatting
* Change two more places where there was a cast
hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSelector.java
hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSelectorFactory.java
hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaLoadBalanceSimpleSelector.java
hbase-client/src/main/java/org/apache/hadoop/hbase/client/CatalogReplicaMode.java
Make the leading license comment opener align on all these new
files.... one star rather than two.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/CatalogReplicationSource.java
Add some comment better situating the catalogreplicationsource
specialization.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java
Add comment how this differs from replicationsource factory and why no
need to keep offset up in zk.
src/main/asciidoc/_chapters/architecture.adoc
Clean up the read replica of META doc. Introduce the new read replica
liveness on META and the new 'LoadBalance' feature (with warnings).
General edit.
It adds load balance support for meta lookup in AsyncTableRegionLocator.
The existing meta replica mode is renamed as "HedgedRead", client sends scan request to the primary meta replica region first,
if response is not back within a configured amount of time, it will send scan requests to all meta replica regions and
take the first response. On top of the existing mode, a new mode "LoadBalance" is introduced. In this mode, client first
choose a meta replica region to send scan request. If the response is stale, it may send the request to another meta replica region or
the primary region. In this mode, meta scan requests are load balanced across all replica regions with the primary mode as
the ultimate source of truth.
Two new config knobs are added:
1. hbase.locator.meta.replicas.mode
Valid options are "None", "HedgedRead" and "LoadBalance", they are case insensitive. The default mode is "None".
2. hbase.locator.meta.replicas.mode.loadbalance.selector
The load balance alogrithm to select a meta replica to send the requests.
Only org.apache.hadoop.hbase.client.CatalogReplicaLoadBalanceReplicaSimpleSelector.class
is supported for now, which is the default as well. The algorithm works as follows:
a. Clients select a randome meta replica region to send the requests if there is no entry for the location in the stale
location cache.
b. If the location from one meta replica region is stale, a stale entry will be created in the statle location cache
for the region.
c. Clients select the primary meta region if the location is in the stale location cache.
d. The stale location cache entries time out in 3 seconds.
If there is no "hbase.locator.meta.replicas.mode" configured, it will check the config knob "hbase.meta.replicas.use".
If "hbase.meta.replicas.use" is configured, the mode will be set to "HedgedRead".
For branch-2 support, it introduces support for ReversedScan over a specific non-default replica region, this is mainly
for load balance meta scan among all its replica regions.
Remove ConnectionImplementation#setUseMetaReplicas()
warmupRegion called by Master on Region move will instatiate
the meta WALProvider as part of its action making it so
it is already created by the time we go to open the
hbsae:meta Region. Accommodate meta walProvider
being already up.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/handler/AssignRegionHandler.java
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/handler/UnassignRegionHandler.java
Pass regionInfo. Needed internally.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java
Add handling if meta wal provider already instantiated when
addCatalogReplicationSource runs.
hbase-server/src/test/java/org/apache/hadoop/hbase/replication/regionserver/TestMetaRegionReplicaReplicationEndpoint.java
Add exercising moving meta around between servers. Test replication
keeps working.
* HBASE-25055 Add ReplicationSource for meta WALs; add enable/disable when hbase:meta assigned to RS
Fill in gap left by HBASE-11183 'Timeline Consistent region replicas - Phase 2 design'.
HBASE-11183 left off implementing 'async WAL Replication' on the hbase:meta
Table; hbase:meta Table could only do Phase 1 Region Replicas reading
the primary Regions' hfiles. Here we add 'async WAL Replication' to
hbase:meta so Replicas can be more current with the primary's changes.
Adds a 'special' ReplicationSource that reads hbase:meta WAL files and replicates
all edits to the configured in-cluster endpoint (Defaults to the
RegionReadReplicaEndpoint.class -- set hbase.region.replica.catalog.replication to
target a different endpoint implementation).
Set hbase.region.replica.replication.catalog.enabled to enable async WAL
Replication for hbase:meta region replicas. Its off by default.
The CatalogReplicationSource for async WAL Replication of hbase:meta does
NOT need to keep up WAL offset or a queue of WALs-to-replicate in the
replication queue store as is done in other ReplicationSource implementations;
the CatalogReplicationSource is for Region Replicas only. General
Replication does not replicate hbase:meta. hbase:meta Region Replicas reset
on crash of the primary replica so there is no need to 'recover'
replication that was running on the crashed server.
Because it so different in operation, the CatalogReplicationSource is bolted
on to the side of the ReplicationSourceManager. It is lazily
instantiated to match the lazy instantiation of the hbase:meta
WALProvider, created and started on the open of the first Region of an
hbase:meta table. Thereafter it stays up till the process dies, even if
all hbase:meta Regions have moved off the server, in case a hbase:meta
Region is moved back (Doing this latter simplifies the implementation)
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java
Read configuration to see if we need to wait on setting a Region read-enabled
(if so, replicas will only flip to enable read after confirming a
flush of the primary so they for sure are a replica of a known point)
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/handler/AssignRegionHandler.java
If configured, on open of hbase:meta, ask the ReplicationSourceManager
to add a ReplicationSource (if it hasn't already).
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/handler/RegionReplicaFlushHandler.java
Edit log message.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/handler/UnassignRegionHandler.java
If configured, on close of hbase:meta, update ReplicationSourceManager
that a source Region has closed.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceFactory.java
javadoc and make constructor private.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceInterface.java
Add logPositionAndCleanOldLogs w/ default of the old behavior so
CatalogReplicationSource can bypass updating store with WAL position,
etc.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceManager.java
Add creation and start of an CatalogReplicationSource.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSourceShipper.java
Go via ReplicationSource when calling logPostionAndCleanOldLogs so new RS can intercept.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/WALFileLengthProvider.java
Javadoc.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/ServerRegionReplicaUtil.java
Add utility for reading configurations for hbase:meta region replicas.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WALFactory.java
Javadoc.
hbase-server/src/test/java/org/apache/hadoop/hbase/replication/regionserver/TestRegionReplicaReplicationEndpoint.java
Use define.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/CatalogReplicationSource.java
Specical version of ReplicationSource for Region Replicas on hbase:meta.
hbase-server/src/main/java/org/apache/hadoop/hbase/replication/regionserver/CatalogReplicationSourcePeer.java
Needs a special peer too (peers are baked into replication though we don't use 'peers' here)
hbase-server/src/test/java/org/apache/hadoop/hbase/replication/regionserver/TestMetaRegionReplicaReplicationEndpoint.java
hbase-server/src/test/java/org/apache/hadoop/hbase/wal/TestWALProvider.java
Tests.
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Huaxiang Sun <huaxiangsun@apache.com>
Pass WALFactory to Replication instead of WALProvider. WALFactory has all
WALProviders in it, not just the user-space WALProvider. Do this so
ReplicationService has access to all WALProviders in the Server (To be
exploited by the follow-on patch in HBASE-25055)
Add new metric rpcFullScanRequestCount to track number of requests that are full region scans. Can be used to notify user to check if this is truly intended.
Signed-off-by Anoop Sam John <anoopsamjohn@apache.org>
Signed-off-by Ramkrishna S Vasudevan <ramkrishna@apache.org>
HBase UI is currently using in bootstrap 3.3.7. This version is vulnerable to 4
medium CVEs (CVE-2018-14040, CVE-2018-14041, CVE-2018-14042, and CVE-2019-8331).
Details on all the bootstrap versions and vulnerabilities is
here: https://snyk.io/vuln/npm:bootstrap
Upgrading to bootstrap 4 would be nice, but potentially more work to do. We
should at least upgrade to the latest bootstrap 3, which is 3.4.1 currently.
closes#2661
Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org>
Signed-off-by: Peter Somogyi <psomogyi@apache.org>
Prior to this patch hbase always used the MD5 hash algorithm to store a hash for encryption keys.
This hash is needed to verify the secret key of the subject. (e.g. making
sure that the same secrey key is used during encrypted HFile read and write).
The MD5 algorithm is considered weak, and can not be used in some
(e.g. FIPS compliant) clusters.
In this patch we:
- add a config parameter to globally enable/disable column family encryption (def enabled)
- introduce a backward compatible way of specifying the hash algorithm.
This enable us to use newer and more secure hash algorithms like SHA-384
or SHA-512 (which are FIPS compliant).
- add a config parameter to fail if an hfile is encountered that uses a
different hash algorithm than the one currently configured to ease validation after
migrating key hash algorithms (def disabled)
Closes#2539
Signed-off-by: Sean Busbey <busbey@apache.org>
Signed-off-by: Esteban Gutierrez <esteban@apache.org>
(cherry picked from commit 6a5c928539)
If hbase.regionserver.close.wait.abort is set to true, interrupt RPC
handler threads holding the region close lock.
Until requests in progress can be aborted, wait on the region close lock for
a configurable interval (specified by hbase.regionserver.close.wait.time.ms,
default 60000 (1 minute)). If we have failed to acquire the close lock after
this interval elapses, if allowed (also specified by
hbase.regionserver.close.wait.abort), abort the regionserver.
We will attempt to interrupt any running handlers every
hbase.regionserver.close.wait.interval.ms (default 10000 (10 seconds)) until
either the close lock is acquired or we reach the maximum wait time.
Define a subset of region operations as interruptible. Track threads holding
the close lock transiting those operations. Set the thread interrupt status
of tracked threads when trying to close the region. Use the thread interrupt
status where safe to break out of request processing.
Signed-off-by: Bharath Vissapragada <bharathv@apache.org>
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Reid Chan <reidchan@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
Wire up the `ConfigurationObserver` chain for
`RegionNormalizerManager`. The following configuration keys support
hot-reloading:
* hbase.normalizer.throughput.max_bytes_per_sec
* hbase.normalizer.split.enabled
* hbase.normalizer.merge.enabled
* hbase.normalizer.min.region.count
* hbase.normalizer.merge.min_region_age.days
* hbase.normalizer.merge.min_region_size.mb
Note that support for `hbase.normalizer.period` is not provided
here. Support would need to be implemented generally for the `Chore`
subsystem.
Signed-off-by: Bharath Vissapragada <bharathv@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
Signed-off-by: Aman Poonia <aman.poonia.29@gmail.com>
The core change here is to the loop in
`SimpleRegionNormalizer#computeMergeNormalizationPlans`. It's a nested
loop that walks the table's region chain once, looking for contiguous
sequences of regions that meet the criteria for merge. The outer loop
tracks the starting point of the next sequence, the inner loop looks
for the end of that sequence. A single sequence becomes an instance of
`MergeNormalizationPlan`.
Signed-off-by: Huaxiang Sun <huaxiangsun@apache.org>
Remove the RegionStates.include method as its name is ambiguous.
Add more comments to describe the logic on why we filter region like
this.
Signed-off-by: Toshihiro Suzuki <brfrn169@gmail.com>
Modified compared to main branch to deprecate obviated MasterObserver interface methods instead of remove them.
Signed-off-by: Sean Busbey <busbey@apache.org>
(cherry picked from commit c5ca191921)
Conflicts:
hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/VerifyingRSGroupAdmin.java
hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestWithDisabledAuthorization.java
* HBASE-25065 - WAL archival to be done by a separate thread
* Fix checkstyle comments
* Fix compile issue
* Fix checkstyle and make the failing test more reliable
* Remove unused import
Implement a rate limiter for the normalizer. Implemented in terms of
MB/sec of affacted region size (the same metrics used to make
normalization decisions). Uses Guava `RateLimiter` to perform the
resource accounting. `RateLimiter` works by blocking (uninterruptible
😖) the calling thread. Thus, the whole construction of the normalizer
subsystem needed refactoring. See the provided `package-info.java` for
an overview of this new structure.
Introduces a new configuration,
`hbase.normalizer.throughput.max_bytes_per_sec`, for specifying a
limit on the throughput of actions executed by the normalizer. Note
that while this configuration value is in bytes, the minimum honored
valued `1_000_000`. Supports values configured using the
human-readable suffixes honored by `Configuration.getLongBytes`
Signed-off-by: Viraj Jasani <vjasani@apache.org>
Signed-off-by: Huaxiang Sun <huaxiangsun@apache.com>
Signed-off-by: Michael Stack <stack@apache.org>
Make it so WALPlayer can replay recovered.edits files.
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/WALInputFormat.java
Allow for WAL files that do NOT have a startime in their name.
Use the 'generic' WAL-filename parser instead of the one that
used be local here. Implement support for 'startTime' filter.
Previous was just not implemented.
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/WALPlayer.java
Checkstyle.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/AbstractFSWALProvider.java
Use the new general WAL name timestamp parser.
hbase-server/src/main/java/org/apache/hadoop/hbase/wal/WAL.java
Utility for parsing timestamp from WAL filename.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRecoveredEdits.java
Export attributes about the local recovered.edits test file
so other tests can play with it.
Signed-off-by: Wellington Chevreuil <wchevreuil@apache.org>
Change the test to wait for evidence that the active master has seen
that the backup master killed by the test has gone away. This is done
before proceeding to validate that the dead backup is correctly
omitted from the ClusterStatus report.
Also, minor fixup to several assertions, using `assertEquals` instead
of `assertTrue(...equals(...))` and correcting expected vs. actual
ordering of assertion arguments.
Signed-off-by: Michael Stack <stack@apache.org>
Give the comparator a more descriptive name, a better location,
and make it work even when passed hbase:meta WAL files.
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Guanghao Zhang <zghao@apache.org>
Pass WALFactory to Replication instead of WALProvider. WALFactory has all
WALProviders in it, not just the user-space WALProvider. Do this so
ReplicationService has access to all WALProviders in the Server (To be
exploited by the follow-on patch in HBASE-25055)
Signed-off-by: Duo Zhang <zhangduo@apache.org>
huaxiangsun
Toshihiro Suzuki
shahrs87
haxiaolin
Michael Stack
Sandeep Pal
stack
bitterfox
Baiqiang Zhao
Duo Zhang
Peter Somogyi
meiyi
Wellington Ramos Chevreuil
Anoop Sam John
Narges Shadab
Andrew Purtell
Rahul Kumar
Akshay Sudheer
Mohammad Arshad
Balazs Meszaros
XinSun
pustota2009
YutSean
Pankaj
Bharath Vissapragada
Aman Poonia
Christine Feng
Anjan Das
Tak Lon (Stephen) Wu
caroliney14
Viraj Jasani
xijiawen
Bo Cui
lujiefsi
ramkrish86
Sandeep Pal
GeorryHuang
Lokesh Khurana
Qi Yu
Mate Szalay-Beko
niuyulin
Huaxiang Sun
gkanade
WenFeiYi
gvprathyusha6
bsglz
Nick Dimiduk
Minji Kim
Reid Chan
Andor Molnár
Joseph295