Constraints on the Resource Pooling Architecture

Description

openGauss resource pooling is a new cluster architecture launched by openGauss. The DMS and DSS components are used to implement underlying shared storage among multiple nodes in a cluster and real-time memory sharing among nodes. In this way, underlying storage resources are saved, write-once-read-many is supported in a cluster, and real-time consistent read is supported. This document describes the constraints on the resource pooling architecture.

Current Constraints

Note that these are temporary constraints and the features may be supported in the future.

No.	Constraint	Remarks
1	Only segment-page storage is supported. Page-based storage is not supported.	The table creation statement must contain with (segment = on, xxx).
2	Row-store tables are not supported.	None
3	FDW is not supported.	None
4	Unlogged tables are not supported.	None
5	Local temporary tables and global temporary tables are not supported.	None
6	Features with compression are not supported.	None
7	Materialized views are not supported.	None
8	The standby node does not support the operation of starting a transaction.	None
9	XA transactions are not supported.	None
10	When the OM is used for installation, only disk array deployment is supported. Ceph and virtual storage pools are not supported.	None
11	Publication and subscription are not supported.	None
12	The traditional primary/standby architecture cannot be deployed at the same time.	That is, a cluster cannot use both the resource pooling primary/standby mode and the traditional primary/standby mode. That is, the replconninfo or hot_standby parameter is not supported.
13	Ustore is not supported.	Flashback is not supported because flashback supports only Ustore.
14	The size of a single Xlog file is changed from 16 MB to 1 GB.	The recycling mechanism is also adapted to 1 GB, and the pg_xlogdump tool is also adapted.
15	You are not advised to disable Global SysCache.	This function is enabled by default and can be disabled through a configuration item. After this function is disabled, the connection may slow down in the case of high concurrency.