PolarDB O Edition allows you to use the cross-node parallel execution feature to query data from partitioned tables to improve the performance of your databases.

Features

The cross-node parallel execution feature allows you to perform the following operations:

  • Query data from range partitions in parallel.
  • Query data from list partitions in parallel.
  • Prune partitions.
  • Query data from partitioned tables that have indexes in parallel.

Limits

  • You can use this feature to run JOIN queries on partitioned tables. However, this feature does not support partition-wise joins. Therefore, the performance of JOIN queries on partitioned tables may be reduced.
  • This feature cannot be used to query data from hash partitions.
  • This feature cannot be used to query data from multi-level partitions.

Instructions

  1. Enable the cross-node parallel execution feature for partitioned tables.
    1. By default, the cross-node parallel execution feature is disabled for partitioned tables. To enable the feature, execute the following statement:
      SET polar_enable_px=on;
    2. To apply the feature to partitioned tables, execute the following statement:
      SET polar_px_enable_partition = true;
  2. For more information about how to create a partitioned table, modify a partitioned table, or query data from a partitioned table, see Command list for partitioned tables.