This topic describes PolarDB for PostgreSQL Standard Edition.
What is PolarDB for PostgreSQL Standard Edition?
PolarDB has supported thousands of customer applications and offered outstanding performance in a real business environment. With its excellent performance, superior stability, and enterprise-tailored advanced features, PolarDB can deliver an unprecedented database experience.
In its early days, PolarDB Enterprise Edition was launched to cater for large enterprises and customers with particular needs. This edition is built on highly customized physical machines and uses PolarStore, a distributed storage developed by Alibaba Cloud. This edition ensures extreme performance and stability, and therefore the cost is relatively high.
With advancing technology and ever-changing market, PolarDB Standard Edition featured by cost-effectiveness is launched. Unlike Enterprise Edition, Standard Edition makes full use of cloud deployment and standardized computing and storage resources. Kernel optimization enables Standard Edition to combine high performance with cost-effectiveness. This ensures deep integration with ECS and cloud disks and offers abundant and flexible computing and storage options. The following figure shows the architecture of PolarDB for PostgreSQL Standard Edition.
PolarDB for PostgreSQL Standard Edition offers higher cost-effectiveness and delivers extreme performance, elasticity, and stability of the cloud-native architecture to more customers.
Differences between Standard Edition and Enterprise Edition
Standard Edition and Enterprise Edition are similar in terms of core architecture and main features. This means that no matter which edition you choose, you can obtain PolarDB core benefits. Standard Edition and Enterprise Edition are different only in hardware and software at the computing and storage layers.
At the computing layer, compute nodes of Enterprise Edition use physical machines without virtualization overheads. Standard Edition uses Elastic Compute Service (ECS) instances.
At the storage layer, Enterprise Edition provides two options: PolarStore Level 4 (PSL4) and PSL5. The two options vary in their performance metrics, such as input/output operations per second (IOPS) and read/write bandwidth. These performance metrics depend on the specifications of compute nodes and are independent of the actual storage capacity. This design ensures consistent and predictable performance for Enterprise users regardless of storage capacity.
Standard Edition has more storage options. Standard Edition uses standard cloud disk technology in the cloud and offers multiple performance options such as PL0, PL1, PL2, PL3, and AutoPL. In contrast to Enterprise Edition, the performance metrics for these options vary with the storage capacity. A low bandwidth (about 50 IOPS per GB) is provided when you have a small amount of data. The storage performance increases with your data volume to provide a smooth experience for your applications.
Storage and data reliability
PolarDB for PostgreSQL Standard Edition uses a shared storage architecture and stores data in enterprise SSDs (ESSDs). ESSDs use a distributed multi-replica mechanism to provide low latency, high performance, high durability, and high reliability.
ESSDs are ultra-high performance disks developed by Alibaba Cloud. ESSDs use a next-generation distributed block storage architecture and support 25 Gigabit Ethernet networks and Remote Direct Memory Access (RDMA). Each ESSD has low one-way latency and can deliver up to 1 million random read/write IOPS. ESSDs are provided in the following performance levels (PLs):
PL0 ESSD: A PL0 ESSD delivers the basic performance of an ESSD.
PL1 ESSD: A PL1 ESSD provides five times the IOPS and roughly double the throughput compared to a PL0 ESSD.
PL2 ESSD: A PL2 ESSD delivers IOPS and throughput that are approximately twice the IOPS and throughput delivered by a PL1 ESSD.
PL3 ESSD: A PL3 ESSD delivers IOPS that is up to ten times that delivered by a PL2 ESSD and throughput that is up to five times that delivered by the PL2 ESSD. The ESSDs are suitable for business scenarios in which highly concurrent requests must be processed with high I/O performance and at low read and write latencies.
ESSD AutoPL disk: Compared with an ESSD at one of the preceding PLs, an ESSD AutoPL disk decouples IOPS and storage, gives you the flexibility to configure IOPS and storage, and allows you to make some adjustments as needed. This reduces the overall Total Cost of Ownership (TCO).
For more information about the ESSD performance, see ESSDs.
After the storage of an ESSD is exhausted, the disk is locked. In this case, the disk handles only read operations.
Data reliability
ESSDs use a distributed triplicate mechanism to ensure 99.9999999% (nine 9's) data durability. If your business is interrupted within a zone due to hardware failures, data within the zone is copied to an available disk in another zone to ensure data durability and availability. For more information, see Triplicate storage.
Purchase or migrate data to a Standard Edition cluster
You can purchase a PolarDB for PostgreSQL Standard Edition cluster on the PolarDB buy page.
If you are not familiar with PolarDB for PostgreSQL Standard Edition, you can use the PolarDB free trial version first.
PolarDB also allows you to migrate data from ApsaraDB RDS feature. You can migrate data from ApsaraDB RDS to PolarDB when you purchase a new cluster at no additional costs.
You can use Data Transmission Service (DTS) to migrate data from a self-managed PostgreSQL database or an ApsaraDB RDS for PostgreSQL instance to a PolarDB for PostgreSQL cluster.
You can use the pg_dump and pg_restore tools provided in the open source community to migrate data.