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    PolarDB:What is PolarDB for PostgreSQL (Compatible with Oracle)

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    PolarDB:What is PolarDB for PostgreSQL (Compatible with Oracle)

    Last Updated:Jan 24, 2026

    PolarDB is a next-generation cloud-native database from Alibaba Cloud. It uses a storage-compute disaggregation architecture and leverages software-hardware integration to provide a secure and reliable database service that features high performance, mass storage, and elasticity in seconds. PolarDB for PostgreSQL (Compatible with Oracle) is highly compatible with Oracle syntax.

    PolarDB for PostgreSQL (Compatible with Oracle) uses a compute-storage separated architecture. All compute nodes share a single copy of data. It provides resource scaling in minutes, fault recovery in seconds, global data consistency, and free data backup and disaster recovery. PolarDB for PostgreSQL (Compatible with Oracle) combines the stability, reliability, high performance, and scalability of commercial databases with the simplicity, openness, and rapid iteration of open-source databases.

    • Decoupled compute and storage with shared distributed storage.

      It uses a compute-storage decoupled design to meet the business requirements for elastic scaling. Compute nodes share the underlying storage (PolarStore) through the distributed file system (PolarFileSystem), which greatly reduces your storage costs.

    • One writer and multiple readers for read/write splitting.

      PolarDB for PostgreSQL (Compatible with Oracle) uses a multi-node cluster architecture. A cluster has one primary node for read and write operations and one or more read-only nodes. When an application uses the cluster endpoint, PolarDB for PostgreSQL (Compatible with Oracle) provides services through an internal proxy layer (PolarProxy). Application requests are first sent to the proxy before they access the database nodes. The proxy layer handles security authentication and protection. It also parses SQL statements, sends write operations to the primary node, and load-balances read operations across the read-only nodes to implement automatic read/write splitting. For an application, this makes using the cluster as simple as using a single-node database.

    Benefits

    You can use PolarDB for PostgreSQL (Compatible with Oracle) just as you would use Oracle. In addition, PolarDB for PostgreSQL (Compatible with Oracle) offers advantages over traditional Oracle databases:

    • Large capacity

      By default, the storage capacity is up to 500 TB. You no longer need to purchase multiple instances for sharding due to the storage limit of a single instance. This simplifies application development and reduces maintenance overhead.

      Note

      PolarStore (PSL4/PSL5) supports petabyte-level storage. If you require petabyte-level storage, you can contact us to reserve resources.

    • Low cost

      • Shared storage: Because compute and storage are decoupled, you are charged only for computing resources when you add a read-only node. In contrast, traditional read-only nodes include both compute and storage resources, which means you pay an additional storage fee for each added node.

      • Elastic storage: You do not need to configure storage space. Storage space automatically scales based on your data volume. You pay only for the data you use, billed by the hour.

    • High performance

      It greatly improves online transactional processing (OLTP) performance. It supports over 500,000 read requests per second and over 150,000 write requests per second.

    • Scaling within minutes

      The service is based on a compute-storage separation architecture, container virtualization technologies, and shared storage. This lets you add or remove a node in only 5 minutes. The storage capacity automatically scales out online. During the scale-out process, your services are not interrupted.

    • Read consistency

      Cluster endpoints use Log Sequence Numbers (LSNs) to ensure global consistency for read operations. This avoids inconsistencies caused by replication delays between the primary and read-only nodes.

    • Millisecond-level latency (physical replication)

      It uses redo-based physical replication instead of binary log-based logical replication. This improves the efficiency and stability of primary-replica replication. Even Data Definition Language (DDL) operations on large tables, such as adding an index or a field, do not cause replication latency.

    • Fast backup within seconds

      A full database backup takes only 30 seconds, regardless of the data volume. The backup process does not lock the database and has almost no impact on your applications. You can perform backups 24/7.

    • Cross-node parallel execution

      SQL statements can be executed in parallel on multiple nodes. This makes full use of the hardware resources of all compute nodes, such as CPU, memory, and network resources, and accelerates Analytical Query Performance. For more information, see Cross-node parallel execution.

    Pricing

    For more information, see Billable items and visit the buy page of PolarDB clusters.

    Product usage

    You can manage PolarDB for PostgreSQL (Compatible with Oracle) clusters in the following ways. You can perform management tasks such as creating clusters, databases, and accounts.

    • Console: A graphical web interface for ease of use.

    • CLI: You can perform all console operations using the CLI.

    • SDK: You can perform all console operations using the software development kit (SDK).

    • API: You can perform all console operations by making API calls.

    After a PolarDB for PostgreSQL (Compatible with Oracle) cluster is created, you can connect to the PolarDB for PostgreSQL (Compatible with Oracle) cluster in the following ways:

    • DMS: You can connect to a PolarDB cluster using DMS and perform database development tasks on the web-based interface.

    • Client: You can use common database client tools, such as pgAdmin, to connect to PolarDB for PostgreSQL (Compatible with Oracle) clusters.

    Terms

    Understanding the following terms will help you better select and use PolarDB for PostgreSQL (Compatible with Oracle):

    • Cluster: PolarDB for PostgreSQL (Compatible with Oracle) uses a cluster architecture. A cluster contains one primary node and up to 15 read-only nodes.

    • Region: A region is a physical data center. Generally, a PolarDB for PostgreSQL (Compatible with Oracle) cluster should be in the same region as an ECS instance for optimal access performance.

    • Zone: A zone is a physical area within a region that has an independent power supply and network. There is no substantial difference between zones in the same region.

    • Specification: The resource configuration of each node, such as 2 cores and 8 GB of memory.

    Related services

    • ECS: An Elastic Compute Service instance. Accessing a PolarDB for PostgreSQL (Compatible with Oracle) cluster from an ECS instance in the same region over an internal network ensures optimal performance for the PolarDB for PostgreSQL (Compatible with Oracle) cluster. Using an ECS instance with a PolarDB for PostgreSQL (Compatible with Oracle) cluster is a typical business access architecture.

    • Redis: Redis provides a persistent in-memory database service. For high-traffic workloads, you can combine ECS, PolarDB for PostgreSQL (Compatible with Oracle), and Redis to support more read requests and reduce response times.

    • MongoDB: A stable, reliable, and scalable database service that is fully compatible with the MongoDB protocol. If your data structures are diverse, you can store structured data in PolarDB for PostgreSQL (Compatible with Oracle) and unstructured data in MongoDB to meet your various storage needs.

    • DTS: You can use Data Transmission Service (DTS) to migrate on-premises databases to a PolarDB for PostgreSQL (Compatible with Oracle) cluster to the cloud.

    • OSS: Object Storage Service (OSS) is a massive, secure, low-cost, and highly reliable cloud storage service from Alibaba Cloud.