oracle 11g oracle DB writer process DBWR
Database writer DBWn =
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1 database writer process writes dirty value from buffer to disk.
The database writer process writes dirty buffers to disk under the following conditions:
a. When the database issues a checkpoint
b. When a server process can’t find a clean reusable buffer after checking a threshold number of buffers
c. Every 3 seconds
2 DBWn uses least recently used LRU algorithm to write from memory to disk.
3 Oracle provides for the use of multiple database writer processes to share heavy data modification
workloads. You can have a maximum of 20 database writer processes
DBW0 through DBW9, and DBWa through DBWj.
4 show parameter DB_WRITER_PROCESSES
NOTE- dirty value (When a user modify data inside buffer, it is not immediately made permanent
by the database writer process