PolarDB is a new-generation Cloud-native database that is developed by Alibaba Group. This service decouples computing from storage and uses integrated software and hardware. PolarDB is a secure and reliable database service that provides auto scaling, high performance, and mass storage. PolarDB is highly compatible with Oracle.

PolarDB for Oracle uses an architecture that decouples computing from storage. All compute nodes share one set of data. PolarDB allows you to upgrade or downgrade specifications within minutes, and supports disaster recovery within seconds. PolarDB ensures that global data is consistent and offers data backup and disaster recovery for free. PolarDB for Oracle provides the benefits of both commercial databases and open source cloud databases. The benefits of commercial databases include stability, reliability, high performance, and scalability. The benefits of open source cloud databases include ease of use, openness, and self iteration.

  • Computing and storage are decoupled. A distributed storage system is shared by all compute nodes.

    PolarDB for Oracle decouples computing and storage. This way, you can use auto scaling to meet the requirements of your business. All compute nodes share the same underlying storage PolarStore by using the distributed file system PolarFileSystem. This reduces storage costs.

  • Each cluster consists of one primary node and multiple read-only nodes. This allows PolarDB to provide read/write splitting.

    PolarDB for Oracle uses multi-node clusters to provide services. Each PolarDB cluster consists of one primary node and at least one read-only node. You can perform read and write operations on the primary node. PolarDB for Oracle uses PolarProxy to provide external services for the applications that are connected to cluster endpoints. PolarProxy forwards the requests from the applications to database nodes. You can use the proxy to perform authentication, data protection, and automatic read/write splitting. The proxy parses SQL statements, sends write requests to the primary node, and evenly distributes read requests to multiple read-only nodes. The proxy allows applications to access PolarDB for Oracle by using the same method that is used to access a single-node database.


You can use PolarDB for Oracle in the same way as you use Oracle. Compared with traditional databases, PolarDB for Oracle has the following advantages:
  • Large storage capacity

    The maximum storage capacity of a cluster is 100 TB. You do not need to purchase instances for database sharding due to the storage limit of a single host. This simplifies application development and reduces the O&M workload.

  • Low costs
    • Shared storage: PolarDB for Oracle decouples computing and storage. You are charged only for the computing resources when you add read-only nodes to a PolarDB for Oracle cluster. In traditional database solutions, you are charged for both computing and storage resources when you add read-only nodes.
    • Elastic storage: You do not need to specify the storage capacity. The storage capacity is automatically scaled based on the data volume. You are charged on an hourly basis only for the storage that you use.
    • Storage plans: PolarDB for Oracle provides storage plans that are billed based on the subscription billing method. We recommend that you use storage plans to offset the cost of large amounts of data. No discounts are available for storage that is paid for on an hourly basis. The subscription billing method of storage plans offers discounts. Larger discounts are provided for larger storage plans.
  • High performance

    PolarDB for Oracle improves online transaction processing (OLTP) performance and supports more than 500,000 read requests per second and more than 150,000 write requests per second.

  • Elastic scaling within minutes

    PolarDB supports rapid scaling for computing. This is based on container virtualization, shared distributed storage, and compute-storage separation. It requires only 5 minutes to add or remove a node. The storage capability is automatically scaled up. During the scale-up process, your services are not interrupted.

  • Read consistency

    PolarDB uses log sequence numbers (LSNs) for cluster endpoints that have read/write splitting enabled. This ensures global consistency for read operations and prevents the inconsistency that is caused by the replication delay between the primary node and read-only nodes.

  • Millisecond-level latency in physical replication

    PolarDB performs physical replication from the primary node to read-only nodes based on redo logs. The physical replication replaces the logical replication that is based on binary logs. This way, the replication efficiency and stability are improved. No delays occur even if you perform DDL operations on a large table, such as adding indexes or fields.

  • Data backup within seconds

    No more than 30 seconds are required to perform a full backup on a database regardless of the data volume of the database. During the backup, the database is not locked. This minimizes the impact of data backup on your applications. You can specify a point in time to back up the database data based on your business requirements.

  • Parallel execution

    PolarDB for Oracle provides the cross-node parallel execution feature. After you enable this feature, an SQL statement can be executed on multiple nodes in parallel. This way, you can make full use of the hardware resources of all compute nodes, such as CPUs, memory, and network resources. This improves the performance of analytical queries. For more information, see Cross-node parallel execution.


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

Use the service

You can use the following methods to manage PolarDB for Oracle clusters. Cluster management includes creating clusters, databases, and accounts.

  • Console: PolarDB provides a visualized web interface. This simplifies management operations.
  • CLI: You can use Alibaba Cloud CLI to perform all the operations that are available in the console.
  • SDK: You can use PolarDB for Oracle SDK to perform the same operations that you can perform in the console.
  • API: You can call API operations to perform all the operations that are available in the console.

After a PolarDB for Oracle cluster is created, you can connect to the PolarDB for Oracle cluster by using the following methods:

  • DMS: You can connect to a PolarDB cluster by using Data Management System (DMS) and develop databases on the web interface of DMS. For more information, see Use DMS to connect to a cluster.
  • Client: You can use common database clients such as pgAdmin to connect to PolarDB for Oracle clusters.


Before you purchase and use PolarDB for Oracle, we recommend that you familiarize yourself with the following terms:

  • Cluster: A PolarDB for Oracle cluster consists of a primary node and a maximum of 15 read-only nodes. PolarDB for Oracle uses a cluster architecture.
  • Region: A region is a geographic area where a data center is deployed. In most cases, PolarDB for Oracle clusters must be deployed in the same region as ECS instances to ensure optimal access performance.
  • Zone: A zone is a geographic area in a region. Each zone has an independent power supply and network. All zones in a region provide the same services.
  • Specification: A specification specifies the resources on a node. For example, the specification of a node can be 2 CPU cores and 8 GB memory.

Related services

  • ECS: ECS instances serve as cloud servers. If you connect to a PolarDB for Oracle cluster from an ECS instance that is deployed in the same region as the PolarDB cluster over an internal network, the PolarDB for Oracle cluster provides optimal performance. In a typical service architecture, ECS instances are used in combination with PolarDB for Oracle clusters.
  • ApsaraDB for Redis: ApsaraDB for Redis is a database service that supports in-memory storage and persistent storage. In scenarios in which large numbers of access requests exist, you can use ECS, PolarDB for Oracle, and ApsaraDB for Redis to improve the read IOPS and reduce the response time.
  • ApsaraDB for MongoDB: ApsaraDB for MongoDB is a stable, reliable, and scalable database service that is fully compatible with MongoDB protocols. You can store structured data in PolarDB for Oracle and unstructured data in ApsaraDB for MongoDB to meet your various business requirements.
  • Data Transmission Service (DTS): You can use DTS to migrate on-premises databases to PolarDB for Oracle clusters.
  • OSS: Object Storage Service (OSS) is a secure, cost-effective, and reliable cloud storage service that allows you to store a large amount of data.