Memory structure

As shown in the preceding figure, the total memory (OBServer Total Memory) of OceanBase Database is a proportion of the memory of the server and can be configured to an absolute value. Some of the memory is used for system running (System Memory for OBServer), and some for tenants (Allocatable Memory for Tenant). A tenant is equivalent to an instance in a conventional database. Except for the sys tenant, other tenants share the same memory modules. The sys tenant does not have a corresponding meta tenant and its memory consists of a MemStore (Tenant MemStore) for storing incremental data and a KVCache (Tenant Cache Memory). Each user tenant has a corresponding meta tenant. Therefore, the memory for a user tenant consists of the memory for the user tenant itself (Tenant1 MemStore) and the memory for the corresponding meta tenant (Tenant1_meta MemStore). Both the memory for the user tenant itself and the memory for the corresponding meta tenant consist of a MemStore for storing incremental data and a KVCache.