Release Notes for MariaDB Xpand 6.1.1


MariaDB Xpand is a distributed SQL database. This is the second General Availability (GA) release in the MariaDB Xpand 6.1 series.

MariaDB Xpand 6.1.1 was released on 2023-03-24.

Upgrade Procedure

MariaDB Xpand 6.1.1 has a special upgrade procedure:

  1. Before upgrading to Xpand 6.1.1, execute the following GRANT statement to grant the EXECUTE privilege on the system.pdm_sync stored procedure: (XPAND-36776)

       ON PROCEDURE `system`.`pdm_sync`
       TO 'xpand'@'localhost';

    If the privilege is not granted, the upgrade procedure can fail with the following error:

    Synchronizing PDs...  ERROR
    ERROR 1045 (HY000) at line 1: [11281] Permission denied: User
    'xpand'@'localhost' is missing EXECUTE on `system`.`pdm_sync`; transaction
    Please run this statement on the cluster and try again (using install-force):
        GRANT EXECUTE ON PROCEDURE `system`.`pdm_sync` TO 'xpand'@'localhost';
  2. After the privilege has been granted, perform the normal upgrade procedure.

    For details about the normal upgrade procedure, see "Upgrades for MariaDB Xpand".

Notable Changes

Rebalance Mode

MariaDB Xpand 6.1.1 changes the default value of the rebalancer_rebalance_mode system variable from normal to noswap. (XPAND-36618)

In previous releases, when the default value was normal, the Rebalancer could swap slices between nodes as an attempt to improve data distribution, but it would sometimes swap slices too aggressively.

Starting with this release, since the default value is noswap, the Rebalancer does not swap slices between nodes to improve data distribution by default. The old default behavior can be enabled by setting rebalancer_rebalance_mode='normal' with SET GLOBAL:

SET GLOBAL rebalancer_rebalance_mode='normal';

Host Anomaly Detector

MariaDB Xpand 6.1.1 introduces the Host Anomaly Detector, which can help determine the cause of cluster-wide instability, with an initial focus on diagnosing network issues. (XPAND-35831)

Xpand's Host Anomaly Detector aggregates and analyzes the cluster logs to detect issues.

Metrics can be collected by scraping the exposed Prometheus endpoint or by configuring the monitor to export to InfluxDB directly.

For additional information, see "Host Anomaly Detector for MariaDB Xpand".

AWS Security Token Service (STS) Authentication

When performing backup/restore to AWS S3, MariaDB Xpand 6.1.1 introduces environment variable support for configuring AWS Security Token Service (STS) Authentication. (XPAND-36634)

The following environment variables are supported as alternatives to the corresponding parameters in the backup URL:


Environment Variable









Additionally, the AWS_BUCKET environment variable can be used to set the bucket.

When a bucket or parameter is specified in the URL, the URL value takes precedence over the environment variable.

For additional information, see "Fast Backup and Restore with MariaDB Xpand".

Query Optimizer Enhancements

MariaDB Xpand 6.1.1 includes multiple enhancements to the query optimizer that improve the quality of query plans. (XPAND-36184, XPAND-36470, XPAND-36600, XPAND-36612, XPAND-36624)


MariaDB Xpand 6.1.1 improves the performance of clx_import by enabling --sql-statement-shortcut by default. (XPAND-36720)

Issues Fixed

Can Result in Data Loss

  • When the softfail procedure is being performed and binary logging is enabled, Xpand does not always complete binlog reprotect before the softfailed nodes were indicated as ready to be removed, which can cause data corruption. (XPAND-36588)

Can Result in Unexpected Behavior

  • When sierra_predictive_governor is enabled and EXPLAIN is used on a query that would exceed sierra_predictive_governor_threshold if it were executed, an error is raised, and no query plan is returned. (XPAND-36675)

    • In previous releases, the following error is raised:

      ERROR 1 (HY000): [PROCESS_ID] Could not generate plan in sierra:
      sierra_predictive_governor: Excess execution predicted
    • Starting with this release, Xpand returns the query plan and does not raise an error.

  • Large backups stored in cloud storage could not be restored. (XPAND-36700)

    • In previous releases, Xpand uses a 32-bit unsigned integer to specify file size, which limits the maximum size that could be transferred.

    • Starting with this release, Xpand uses a 64-bit unsigned integer to specify file size.

  • I/O performance issues occur when the cluster uses EBS for storage. (XPAND-36678)

    • For best performance, when a cluster uses EBS, CLXNODE_ADDITIONAL_ARGS='-use-libaio' should be set in the Xpand configuration file.

Install and Upgrade

  • Upgrades could result in some tables with missing PDs (probability distributions) until PD sync occurs. (XPAND-36776)

    • Starting with this release, PD sync will be triggered as part of the upgrade process.

Installation Instructions

Upgrade Instructions