Table-level replication
To enable table-level replication, you must specify the list of tables to be replicated in a given replication policy. Table-level replication enables you to replicate just the critical tables. It also helps you to speed-up the replication process and also reduces network bandwidth utilization.
You can define table-level replication using regular expressions. You can include or exclude tables in a database for Hive replication during the Hive replication policy creation process.
The following examples illustrate how you can include or exclude Hive tables in the Hive
replication policy:
- To include only table1, table2, and table3 in a database for replication, enter the database name in the Database field, and then enter table1|table2|table3 in the Tables field.
- To exclude table5, table7, and table9 and include the rest of the tables in the database, enter the database name in the Database field, and then enter (?!table5|table7|table9).+ in the Tables field.
Limitations using table-level replication
- If a table is dynamically added for replication due to changes in regular expression or added to the include list, the tables' data may not be point-in-time consistent with other tables which are already replicated incrementally. However, this inconsistency is seen for a very small duration until the completion of the next incremental replication after tables are added in the bootstrapped manner.
- Hive does not support overlapping replication policies such as db., db.[t1], and *. to the same target database but works as expected if the target databases are different.
