What are 11g New Features
1) Automatic Diagnostic
Repository [ADR]
2) Database Replay
3) Automatic Memory Tuning
4) Case sensitive password
5) Virtual columns and indexes
6) Interval Partition and System
Partition
7) The Result Cache
8) ADDM RAC Enhancements
9) SQL Plan Management and SQL
Plan Baselines
10) SQL Access Advisor &
Partition Advisor
11) SQL Query Repair Advisor
12) SQL Performance Analyzer
(SPA) New
13) DBMS_STATS Enhancements
14) The Result Cache
15) Total Recall (Flashback Data
Archive)
Note: The above are only top new
features, there are other features as well introduced in 11g which will be
included subsequently
11G Background Processes?
The following process are added
in 11g as new background processes.
1 dbrm DB resource manager
2 dia0 Diagnosability process
3 fbda Flashback data archiver
process
4 vktm Virtual Timekeeper
5 w000 Space Management
Co-ordination process
6 smc0 Space Manager process
NOTE : The above six are
mandatory processes.
DBWn writes when __ ?
• Checkpoint occurs
• Dirty buffers reach threshold
• There are no free buffers
• Timeout occurs
• RAC ping request is made
• Tablespace OFFLINE
• Tablespace READ ONLY
• Table DROP or TRUNCATE
• Tablespace BEGIN BACKUP
Log Writer (LGWR) writes:
• At commit
• When 1/3rd full
• When there is 1 MB of redo
• Every 3 seconds
• Before DBWn writes
What are the Responsibilities of System Monitor (SMON) ?
• Instance recovery
– Rolls forward changes in redo
logs
– Opens database for user access
– Rolls back uncommitted
transactions
• Coalesces free space
• Deallocates temporary segments.
Process Monitor (PMON) Cleans up
after failed processes by:
• Rolling back the transaction
• Releasing locks
• Releasing other resources
• Restarting dead dispatchers
Checkpoint (CKPT) Responsible
for:
• Signaling DBWn at checkpoints
• Updating datafile headers with
checkpoint information
• Updating control files with
checkpoint information
Archiver (ARCn)
• Optional background process
• Automatically archives online
redo logs when ARCHIVELOG mode is set
• Preserves the record of all
changes made to the database
Why should we use separate ASM
home?
ASM should be installed
separately from the database software in its own ORACLE_HOME directory. This
will allow you the flexibility to patch and upgrade ASM and the database
software independently.
How many ASM instances should one
have?
Several databases can share a
single ASM instance. So, although one can create multiple ASM instances on a
single system, normal configurations should have one and only one ASM instance
per system.
What is ASM Rebalancing?
The rebalancing speed is
controlled by the ASM_POWER_LIMIT initialization parameter. Setting it to 0
will disable disk rebalancing
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