Known Issues in Apache HBase

This topic describes known issues and workarounds for using HBase in this release of Cloudera Runtime.

HBASE-24885: If an operator uses HBCK2 to invoke multiple `assigns` operations against one Region or happens to invoke HBCK2 `assigns` while HBase is re-assigning a Region, it is possible that the Region will be abnormally assigned. For example, unassigned, stuck in transition, and doubly-assigned.

Obtain a fix for this issue. Operators should definitely not schedule multiple assigns for a single Region at the same time, however there is still a potential race condition.

OpDB Data Hub cluster fails to initialize if you are reusing a cloud storage location that was used by an older OpDB Data Hub cluster

Workaround: Stop HBase using Cloudera Manager before deleting an operational database Data Hub cluster.

IntegrationTestReplication fails if replication does not finish before the verify phase begins

During IntegrationTestReplication, if the verify phase starts before the replication phase finishes, the test will fail because the target cluster does not contain all of the data. If the HBase services in the target cluster does not have enough memory, long garbage-collection pauses might occur.

Workaround: Use the -t flag to set the timeout value before starting verification.

HDFS encryption with HBase

Cloudera has tested the performance impact of using HDFS encryption with HBase. The overall overhead of HDFS encryption on HBase performance is in the range of 3 to 4% for both read and update workloads. Scan performance has not been thoroughly tested.

Workaround: N/A

AccessController postOperation problems in asynchronous operations

When security and Access Control are enabled, the following problems occur:

• If a Delete Table fails for a reason other than missing permissions, the access rights are removed but the table may still exist and may be used again.
• If hbaseAdmin.modifyTable() is used to delete column families, the rights are not removed from the Access Control List (ACL) table. The portOperation is implemented only for postDeleteColumn().
• If Create Table fails, full rights for that table persist for the user who attempted to create it. If another user later succeeds in creating the table, the user who made the failed attempt still has the full rights.

Workaround: N/A

Apache Issue: HBASE-6992

Bulk load is not supported when the source is the local HDFS

The bulk load feature (the completebulkload command) is not supported when the source is the local HDFS and the target is an object store, such as S3/ABFS.

Workaround: Use distcp to move the HFiles from HDFS to S3 and then run bulk load from S3 to S3.

Apache Issue: N/A