PolarDB O Edition is a next-generation cloud-native relational database service developed by Alibaba Cloud. PolarDB O Edition is highly compatible with the Oracle syntax. A PolarDB O Edition cluster has a storage capacity of up to 100 TB and can contain up to 16 nodes. PolarDB O Edition can meet the business requirements of enterprises in a variety of database application scenarios.
PolarDB O Edition decouples computing and storage. All compute nodes of a PolarDB O Edition cluster share the same physical storage. PolarDB O Edition allows you to upgrade or downgrade instance specifications within a few minutes and perform fault recovery within seconds. This service ensures global data consistency and provides data backup and disaster recovery that are free of charge. PolarDB O Edition incorporates the highlights of commercial databases, including stability, reliability, high performance, and scalability. It also has the following advantages of open source cloud databases: ease of use, openness, and self-iteration.
- Computing and storage are decoupled. A distributed storage system is shared by all compute nodes.
PolarDB O Edition 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 a large amount of storage costs.
- Each cluster consists of one primary node and multiple read-only nodes. This enables read/write splitting.
PolarDB O Edition provides services in multi-node clusters. Each PolarDB O Edition cluster consists of one primary node and at least one read-only node. You can perform both read and write operations on the primary node. A PolarDB O Edition cluster uses an internal proxy named PolarProxy to provide services for the applications that are connected to the endpoint of the cluster. The proxy forwards the requests from the applications to database nodes. You can use the proxy to implement 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 O Edition by using the same method that is used to access a single-node database.
- 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 the development of applications and reduces the O&M workload.
- Low costs
- Shared storage: PolarDB O Edition decouples computing and storage. You are charged only for the computing resources when you add read-only nodes to a PolarDB O Edition 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 set the storage to a limited 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 plan: PolarDB O Edition 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 by the hour. The subscription billing method of storage plans offers discounts. Larger discounts are provided for larger storage plans.
- High performance
PolarDB O Edition 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 O Edition decouples computing and storage and supports container-based virtualization. All compute nodes in a cluster share a storage system. Only 5 minutes is required to add or remove a node. The storage capacity is automatically scaled up without interrupting your services.
- Read consistency
Replication lag between the primary node and read-only nodes may cause inconsistency between data read operations. Therefore, log sequence numbers (LSNs) are included in the cluster endpoints to ensure global consistency for read operations.
- Millisecond-level latency in physical replication
PolarDB O Edition performs physical replication from the primary node to read-only nodes based on redo logs instead of logical replication based on binary logs. This improves the replication efficiency and stability. 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 is required to perform a full backup on a database that contains a large amount of data. During the backup, the database is not locked. This minimizes the impact of data backup on your applications. You can specify a time to back up the data based on your business requirements.
- Parallel execution
PolarDB O Edition 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 the compute nodes, such as CPUs, memory, and network resources. This improves the performance of analytical queries. For more information, see Cross-node parallel execution.
Use the service
You can use the following methods to manage PolarDB O Edition clusters. For example, you can create clusters, databases, and accounts.
- Console: The console is a web-based user interface that is easy to use.
- CLI: You can use the CLI provided by PolarDB O Edition to perform the same operations that you can perform in the console.
- SDK: You can use PolarDB O Edition SDK to perform the same operations that you can perform in the console.
- API: You can call API operations to perform the same operations that you can perform in the console.
After a PolarDB O Edition cluster is created, you can connect to the cluster by using the following methods:
- Data Management (DMS): You can connect to a PolarDB O Edition cluster by using DMS and develop databases in the DMS console. For more information, see Use DMS to connect to a PolarDB O Edition cluster.
- Client: You can use common database clients, such as pgAdmin, to connect to PolarDB O Edition clusters.
Before you purchase and use PolarDB O Edition, we recommend that you understand the following terms:
- Cluster: PolarDB O Edition provides services in clusters. A PolarDB O Edition cluster contains one primary node and a maximum of 15 read-only nodes.
- Region: A region is a geographic area where a data center is deployed. In most cases, a PolarDB O Edition cluster must be deployed in the same region as the Elastic Compute Service (ECS) instance that is used to access the cluster. This optimizes the cluster 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.
- ECS: ECS instances are cloud servers. If you want to access a PolarDB O Edition cluster, we recommend that you use an ECS instance that is deployed in the same region to connect to the cluster over an internal network. This ensures the optimal cluster performance. ECS instances are commonly used to access PolarDB O Edition clusters.
- ApsaraDB for Redis: ApsaraDB for Redis is a database service that supports in-memory storage and persistent storage. You can combine ECS instances, PolarDB O Edition clusters, and ApsaraDB for Redis instances to handle a large number of read requests and reduce the response time.
- ApsaraDB for MongoDB: ApsaraDB for MongoDB is a stable, reliable, and automatically scalable database service that is fully compatible with MongoDB protocols. If a variety of data structures are used to organize your data, you can store structured data in PolarDB O Edition and unstructured data in ApsaraDB for MongoDB.
- DTS: You can use Data Transmission Service (DTS) to migrate on-premises databases to PolarDB O Edition 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.