Each OBServer runs a single observer process. An observer process uses many threads, which can be divided into worker threads and background threads.
Worker threads
A thread that processes SQL and transaction requests is referred to as a worker thread. Each tenant has its own worker threads.
Background threads
OBServer uses the following background threads:
net io: the thread that processes the network I/O.
disk io: the thread that processes disk I/O.
dag thread: the thread that performs tasks such as the minor compaction, major compaction, and migration of partitions.
clog writer: the thread that writes clogs.
election worker: the thread that is used for leader election.
misc timer: a set of background timer threads that are used to clear resources.
In addition, the RootServer contains many dedicated threads. OBServers also use other background threads for specific purposes. These threads are not described in this topic.