oracle server = instance + database
instance = SGA + background process
each server process and background process has one PGA
user process - server process - instance
database buff cache: pinned(multiple sessions wait to write to the same block. other sessions wait to access this block )
cleaned: unpinned and ready to use.
free or unused: the instance just started.
dirty: the buffer is no longer pinned but contents (data block) have changed and must beflushed to sidk by DBWn before it can be aged out.
data files: contain user or application data
online redo log files: used to recover.
archive log file: enable the recovery of restored data files
A database is devided into table spaces.
table spaces contain data files.
Table space - SYSTEM, SYSAUX are mandatory and must be on line
SYSTEM - core functinality
SYSAUX - additional db compenent(ex. Enterprise Manager Repository)
schema is a collection of db objects
instance = SGA + background process
each server process and background process has one PGA
user process - server process - instance
database buff cache: pinned(multiple sessions wait to write to the same block. other sessions wait to access this block )
cleaned: unpinned and ready to use.
free or unused: the instance just started.
dirty: the buffer is no longer pinned but contents (data block) have changed and must beflushed to sidk by DBWn before it can be aged out.
data files: contain user or application data
online redo log files: used to recover.
archive log file: enable the recovery of restored data files
A database is devided into table spaces.
table spaces contain data files.
Table space - SYSTEM, SYSAUX are mandatory and must be on line
SYSTEM - core functinality
SYSAUX - additional db compenent(ex. Enterprise Manager Repository)
schema is a collection of db objects
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