Known Issues in Apache HBase

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

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 loading into HBase configured to use cloud storage (S3) is currently not supported

When HBase is configured to use cloud storage (S3), bulk loading data into HBase fails with the following error: 401 Authentication required.

Workaround: N/A

Apache Issue: N/A

Storing Medium Objects (MOBs) in HBase is currently not supported

Storing MOBs in HBase relies on bulk loading files, and this is not currently supported when HBase is configured to use cloud storage (S3).

Workaround: N/A

Apache Issue: N/A