Use the cross-node parallel execution feature to query data from partitioned tables

Overview

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.
• Query data from hash partitions in parallel.
• Prune partitions.
• Query data from partitioned tables that have indexes in parallel.
• Use JOIN to query data from partitioned tables.
• This feature cannot be used to query data from multi-level partitions.

Limits

This feature cannot be used to query data from hash partitions in which data is partitioned by more than one column.

Usage

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 enable the cross-node parallel execution feature for partitioned tables, execute the following statement:

   SET polar_px_enable_partition = true;

3. To enable the cross-node parallel execution feature for multi-level partitioned tables, execute the following statement:

   set  polar_px_optimizer_multilevel_partitioning = true;