Improving the performance of rebalancing

SarahLSarahL Administrator, Moderator, Employee, Registered User, VerticaExpert, CABuser

This tip was authored by Jim Knicely.

Before performing a rebalance, Vertica by default will query system tables to compute the size of all projections involved in the rebalance task. This query can add significant overhead to the rebalance operation!

To disable this query, set the configuration parameter RebalanceQueryStorageContainers to 0.

Example:

dbadmin=> SELECT DISTINCT parameter_name, current_value, default_value, description
dbadmin->   FROM vs_configuration_parameters
dbadmin->  WHERE parameter_name = 'RebalanceQueryStorageContainers';
         parameter_name          | current_value | default_value |              description
---------------------------------+---------------+---------------+----------------------------------------
RebalanceQueryStorageContainers | 1             | 1             | Check storage containers for rebalance
(1 row)

dbadmin=> ALTER DATABASE wwt SET RebalanceQueryStorageContainers = 0;
ALTER DATABASE

dbadmin=> SELECT DISTINCT parameter_name, current_value, default_value, description
dbadmin->   FROM vs_configuration_parameters
dbadmin->  WHERE parameter_name = 'RebalanceQueryStorageContainers';
         parameter_name          | current_value | default_value |              description
---------------------------------+---------------+---------------+----------------------------------------
RebalanceQueryStorageContainers | 0             | 1             | Check storage containers for rebalance
(1 row)

Have Fun!

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