Filter
Top Products
System Architecture 2-33
OnLine Daemon Processes
OnLine Daemon Processes
Daemon processes are OnLine user processes that perform system-wide
tasks. Unlike database server processes, a daemon process is not associated
with a corresponding application development tool process.
The OnLine system employs three different types of daemons, which are
listed below.
■ tbinit, the master daemon
■ tbundo, the undertaker daemon
■ tbpgcl, a page-cleaner daemon
Daemon processes are identified in tbstat -u output by a D (daemon) flag or
an F (page cleaner or “flusher”) flag in the fourth flag position of the user
entry.
tbinit Daemon
The tbinit daemon is spawned by the tbinit process early in the initialization
process. The tbinit daemon occupies the first entry in the shared-memory
user table, which is represented by the first entry in tbstat -u output.
The tbinit daemon is responsible for most of the tasks of disk space and
shared-memory initialization. (Refer to page 2-7.)
The tbinit daemon also schedules the work of the page-cleaner daemons. If
no page-cleaner daemons exist, tbinit takes over page-cleaning responsibil-
ities. (Refer to page 2-74 for a detailed explanation of buffer page flushing,
which is the responsibility of the page-cleaner daemons.)