Replicating Data to Impala Clusters
Impala metadata is replicated as part of regular Hive/Impala replication operations.
Replicating Impala Metadata
Impala metadata replication is performed as a part of Hive replication. Impala replication is only supported between two CDH clusters. The Impala and Hive services must be running on both clusters.
- Schedule Hive replication.
- Confirm that the Replicate Impala Metadata option is set to Yes on the Advanced tab in the Create Hive Replication dialog.
Invalidating Impala Metadata
For Impala clusters that do not use LDAP authentication, you can
configure Hive/Impala replication jobs to automatically invalidate
Impala metadata after replication completes. If the clusters use Sentry,
the Impala user should have permissions to run
The configuration causes the Hive/Impala replication job to run the
INVALIDATE METADATA statement per table on the
destination cluster after completing the replication. The statement
purges the metadata of the replicated tables and views within the
destination cluster's Impala upon completion of replication, allowing
other Impala clients at the destination to query these tables
successfully with accurate results. However, this operation is
potentially unsafe if DDL operations are being performed on any of the
replicated tables or views while the replication is running. In general,
directly modifying replicated data/metadata on the destination is not
recommended. Ignoring this can lead to unexpected or incorrect behavior
of applications and queries using these tables or views.
- Schedule a Hive/Impala replication.
- On the Advanced tab, select the Invalidate Impala Metadata on Destination option.
Alternatively, you can run the
INVALIDATE METADATA statement manually for