Опубликовано пн, 12/23/2013 - 17:03 пользователем talifa
| SMON | System Monitor | SMON mounts a database by locating and validating the database controlfile. It then opens a database by locating and validating all the datafiles and online log files. Once the database is opened and in use, SMON is responsible for various housekeeping tasks, such as coalescing free space in datafiles. Cleanup unused temporary segments |
| PMON | Process Monitor | monitors all the server processes and detects any problems with the sessions. If a session has terminated abnormally, PMON will destroy the server process, return its PGA memory to the operating system’s free memory pool |
| DBWn | Database Writer | Алгоритм DBWn скидывает на диск грязные буферы (который будет чистить их) будет выбирать только буферы, которые в последнее время не используются. What will cause DBWR to write? No free buffers, too many dirty buffers, a three-second timeout, or a checkpoint. |
| LGWR | Log Writer | |
| CKPT | Checkpoint Process | |
| MMON | Manageability Monitor | Трансфер статистики с SGA на диск через промежутки времени. И устанавливает метрики по умолчанию. |
| MMAN | Memory Manager | менеджер памяти |
| ADDM | Automatic Database Diagnostic Monitor | анализирует данные в Automatic Workload Repository (AWR) для выявления потенциальных узких мест в производительности, хранит причины и рекомендации там же в AWR |
| ARCn | Archiver | |
| RECO | Recoverer | |
1: Perform recovery at instance startup.
2: Free the resources used by a user process when it fails.
3: Cleanup the database buffer cache when a process fails.
4: Dynamically register database services with listeners.
5: Monitor sessions for idle session timeout.
6: Cleanup unused temporary segments.
7: Record the checkpoint information in control file.
A.Checkpoint (CKPT): 7
B.System Monitor (SMON): 1, 6
C.Process Monitor (PMON): 2,4,5,7
D.Database Writer (DBWR): 3,
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