PolarDB for PostgreSQL provides the cross-node parallel execution feature. If this feature is enabled, an SQL query can be run on multiple compute nodes in a distributed manner. This improves the query performance of PolarDB for PostgreSQL, increases the I/O throughput of Polar File System (PolarFS) and the CPU utilization of the compute nodes, and improves the memory usage of the compute nodes.

Prerequisites

  • The cross-node parallel execution feature is enabled for your cluster. To apply to use the feature, submit a ticket.
  • The minor version of the PolarDB for PostgreSQL kernel is V1.1.11 or later. For more information about how to upgrade the minor version of the kernel, see Version Management.

Benefits

The cross-node parallel execution feature provides the following benefits:

  • Some hybrid transaction/analytical processing (HTAP) capabilities:
    • Analytical queries on transaction processing (TP) data can be run in real time.
    • The read-only nodes on which analytical queries are run are physically isolated from the read-only nodes on which transactional queries are run. This eliminates the impact on TP services.
  • Elastic scaling enabled by the compute-storage separation architecture of PolarDB for PostgreSQL:
    • Read-only nodes can be added based on your business requirements to increase computing resources. The added nodes are automatically included in the list of read-only nodes on which parallel execution is performed in a distributed manner. This way, the system does not need to perform resharding on data.
    • No data skew occurs.

Scenarios

This feature is suitable for business scenarios that require simple analysis, such as reconciliation.

Feature overview

  • You can use the cross-node parallel execution feature to run analytical queries. This way, you can use specific HTAP capabilities based on your business requirements. For more information, see Use the cross-node parallel execution feature to run analytical queries.

  • You can use the cross-node parallel execution feature to accelerate the process of creating indexes. For more information, see Use cross-node parallel execution to accelerate index creation.
  • You can use the cross-node parallel execution feature to scan BRIN indexes. To enable the cross-node parallel execution feature, set the polar_enable_px parameter to on. This way, you can use BRIN indexes to improve query performance.