OceanBase Database is single-process. In OceanBase Database, a part of threads are system threads that maintain the distributed database services, and other threads are worker threads that manage database loads.
Types of OceanBase Database threads
OceanBase Database threads are classified into the following types:
Tenant threads: Tenant threads handle tenant requests, such as SQL statements and transaction requests. Tenant threads are named in the
TNT_L<n>_<tenant id>format.System threads:
net io: handles network I/O.
disk io: handles disk I/O.
dag thread: executes tasks such as dump (mini and minor compactions), merge (major compactions), and migration of partitions.
clog writer: writes clogs.
election worker: performs leader election.
misc timer: a set of background timer threads that are used to clear resources.
In addition, there are RootServer dedicated threads, which are not detailed here.
OceanBase Database also uses background threads for specific purposes. If you are a beginner with OceanBase Database, you do not need to learn about these threads.
Each tenant has specific tenant threads that execute requests of the tenant. System threads ensure the normal running of the observer process on the node, process requests, and are shared by tenants.
More information
For more information about OceanBase Database threads, see Thread introduction.