What’s New in PolarDB‑X 2.4.1? Cloud Backup, Online DDL, Physical Scaling & TTL Explained

PolarDB‑X v2.4.1 Highlights

PolarDB‑X 2.4.1 focuses on enterprise‑grade operational capabilities, adding cloud backup set restore, online DDL, physical scaling, and data TTL features to improve multi‑cloud deployment and large‑scale distributed management.

Open‑source Timeline

2021‑10: Open‑source release at Cloud Xi conference.

2022‑01: v2.0.0 – cluster scaling and binlog compatibility.

2022‑03: v2.1.0 – Paxos‑based three‑replica consensus.

2022‑05: v2.1.1 – hot/cold data separation.

2022‑10: v2.2.0 – enterprise and ARM adaptation.

2023‑03: v2.2.1 – production‑grade critical capabilities.

2023‑10: v2.3.0 – standard (centralized) edition with MySQL compatibility.

2024‑04: v2.4.0 – columnar storage node with clustered columnar index.

Cloud Backup Set Restore

PolarDB‑X supports restoring clusters from commercial backup sets, enabling multi‑cloud disaster recovery and offline testing. The process consists of importing the backup set and launching a restore task.

docker run -d -v /root/config:/config --network=host \
  --name=polardbx-backupset-importer \
  --entrypoint="/backupset-importer" \
  polardbx-opensource-registry.cn-beijing.cr.aliyuncs.com/polardbx/backupset-importer:v1.7.0 \
  -conf=/config

The operator can also create instances directly from imported backup sets via the PolarDB‑X Operator.

Online DDL with OMC Algorithm

PolarDB‑X v2.4.1 introduces a native lock‑free column modification capability called OMC (Online Modify Column), offering better incremental sync, smart throttling, and multi‑version metadata switching.

ALTER TABLE tbl_name 
    alter_option [, alter_option] ...
    ALGORITHM = OMC

Example demo:

# Create test table
CREATE TABLE t1(a int primary key, b tinyint, c varchar(10)) partition by key(a);

# Modify column types using OMC
ALTER TABLE t1 MODIFY COLUMN b int, MODIFY COLUMN c varchar(30), ALGORITHM=OMC;

# Change column name and add a new column
ALTER TABLE t1 CHANGE COLUMN b d int, ADD COLUMN e bigint AFTER d, ALGORITHM=OMC;

Physical Scaling Improvements

Version 2.4.1 replaces logical data migration with physical file‑based full‑copy, reducing CPU overhead and increasing parallelism for both scale‑out and scale‑in operations.

# Enable physical backfill migration
set global physical_backfill_enable=true;
# Disable it
set global physical_backfill_enable=false;

Benchmarks show 5‑10× speed gains across various workloads.

Data TTL Support

TTL allows automatic cleanup of cold data while optionally archiving it to object storage via columnar tables.

# Configure TTL on an existing table
ALTER TABLE `orders_test`
MODIFY TTL
SET TTL_EXPR = `date_field` EXPIRE AFTER 2 MONTH TIMEZONE '+08:00';

# Manual cleanup
ALTER TABLE `orders_test` CLEANUP EXPIRED DATA;

# Scheduled cleanup at 2 AM daily
ALTER TABLE `orders_test` MODIFY TTL 
SET TTL_JOB = CRON '0 0 2 */1 * ? *' TIMEZONE '+08:00';

# Create an archive table for expired data
CREATE TABLE `orders_test_archive`
LIKE `orders_test`
ENGINE = 'Columnar' ARCHIVE_MODE = 'TTL';

Architecture Overview

PolarDB‑X follows a shared‑nothing, storage‑separated compute design with five core components:

Compute Node (CN) – stateless SQL parsing, optimization, execution, global 2PC coordination, and enterprise features.

Data Node (DN) – Paxos‑based storage providing strong consistency and MVCC.

Global Meta Service (GMS) – maintains global metadata, accounts, permissions, and provides global timestamp service.

Change Data Capture (CDC) – MySQL‑compatible binlog subscription and replication.

Columnar Node – persistent columnar indexes stored on object storage, enabling HTAP queries.

Deployment Options

Deployment Method

Description

Installation Tool

Dependencies

RPM Package

Zero‑component dependency, manual fast deployment

RPM download & install

rpm

PXD

Proprietary fast‑deployment tool using YAML configuration

PXD install

python3, docker

K8S

Kubernetes Operator‑based deployment

K8S install

k8s, docker

The PolarDB‑X Operator (v1.7.0) provides production‑grade deployment and multi‑cloud backup/restore capabilities.

Summary

PolarDB‑X v2.4.1 delivers significant enterprise‑grade operational enhancements, including cloud backup set restore, native lock‑free DDL, physical scaling, and flexible TTL, while offering multiple deployment paths for on‑premise, multi‑cloud, and Kubernetes environments.