Forgot your password?    
+ Reply to Thread
Results 1 to 3 of 3

Thread: Automatic Memory Management in 11g

  1. #1
    Expert Oracle Administrator
    Join Date
    Oct 2011
    Location
    Delhi, India, India
    Posts
    128

    Thumbs up Automatic Memory Management in 11g

    Automatic Memory Management in 11g
    ------------------------------------
    In Oracle 11g, the automatic memory management feature is developed. Both the system global area (SGA) and the program global area (PGA) will expand and shrink based on the instance demands. To enable this feature, you set the following new parameters:
    MEMORY_TARGET - This parameter sets the system-wide usable memory that will be used by the instance for SGA and PGA.
    MEMORY_MAX_TARGET - This parameter sets the maximum value you can set for MEMORY_TARGET parameter.

    Automatic Memory Management
    In Oracle 11g, a new parameter named as MEMORY_TARGET is added to automate memory allocation for both the SGA and PGA. When this parameter is set, the SGA and the PGA memory sizes are automatically determined by the instance based on the database workload.
    This parameter is dynamic and can be alter using the ALTER SYSTEM command as shown below:
    ALTER SYSTEM SET MEMORY_TARGET = 1024M ;
    However, if the database is not configured to use this parameter and you want to use it, you must restart the database after setting the parameter.
    When you configure the database to use MEMORY_TARGET, you should take into consideration the following:
    The parameter STATISTICS_LEVEL must be set to TYPICAL
    The parameter MEMORY_MAX_SIZE controls the maximum value you can set for MEMORY_TARGET. If you do not set a value for this parameter, it defaults to MEMORY_TARGET.
    If you set the parameters SGA_TARGET and PGA_TARGET, Oracle will consider the values as the minimum values for SGA and PGA.
    If you do not set the parameters SGA_TARGET and PGA_TARGET (or set them to zero), no minimum value is considered by Oracle for the SGA and PGA. When the instance starts, it assigns 60 percent to SGA and 40 percent to the PGA.
    When MEMORY_TARGET is configured, the following components are auto tuned: DB BUFFER CACHE, SHARED POOL, JAVA POOL, LARGE POOL and STREAMS POOL.
    To set a proper value to the parameter MEMORY_TARGET, query the view V$MEMORY_TARGET_ADVICE.
    SELECT * FROM V$MEMORY_TARGET_ADVICE;

    To display current status of the memory components, use the following query:
    SELECT COMPONENT, ROUND(CURRENT_SIZE/1024/1024) CURRENT_SIZE ,
    ROUND(MIN_SIZE/1024/1024) MIN, ROU

    To know how Oracle has modified the memory area sizes by time, issue the following query:
    select START_TIME, END_TIME, STATUS, COMPONENT, OPER_TYPE, OPER_MODE,
    PARAMETER, INITIAL_SIZE/1024/1024 INITIAL_SIZE_MB,
    TARGET_SIZE/1024/1024 TARGET_SIZE_MB, FINAL_SIZE/1024/1024 FINAL_SIZE_MB
    from V$MEMORY_RESIZE_OPS
    order by START_TIME, END_TIME


    Regards,
    -Amit

  2. #2
    Oracle DBA
    Join Date
    Oct 2011
    Posts
    17
    good one!!

  3. #3
    Expert Oracle Administrator
    Join Date
    Oct 2011
    Location
    Delhi, India, India
    Posts
    128
    Thanks Harsh!!
    Regards,
    -Amit

+ Reply to Thread

Similar Threads

  1. Oracle Applications 11i , R12 increase JVM Count and Memory
    By ajaysingh in forum Concepts,Service Management,Apache,OC4J,OPMN,JServ,Forms, Issues,Troubleshooting,
    Replies: 3
    Last Post: 03-01-2012, 02:11 PM
  2. Oracle 11g create spfile from memory.
    By ajaychandi in forum Core Database Administration and Monitoring
    Replies: 0
    Last Post: 12-22-2011, 06:10 PM
  3. Oracle 11g Memory Advisor feature.
    By ajaychandi in forum Database Performance Management,Database Links,Materialized Views
    Replies: 0
    Last Post: 12-20-2011, 02:20 AM
  4. R12 - Enable Automatic Compilation of JSP pages
    By Hemant in forum Concepts,Service Management,Apache,OC4J,OPMN,JServ,Forms, Issues,Troubleshooting,
    Replies: 1
    Last Post: 11-02-2011, 09:34 AM
  5. ORA-27125: unable to create shared memory segment
    By manishkr23 in forum Core Database Administration and Monitoring
    Replies: 3
    Last Post: 10-24-2011, 04:46 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

DBA Lounge (P) Ltd. deals in Oracle Technologies on Consulting, Resourcing, Corporate Training


Online and corporate training available on Oracle Database 11g, Oracle 11g Real Application Cluster (RAC), Oracle Applications 11i/R12, Oracle Fusion Middleware 11g, Oracle Identity Management-OIM, Oracle Internet Directory 11g-OID, Oracle Business Intelligence Enterprise Edition-OBIEE, Oracle Golden Gate, Oracle Access Management-OAM, Oracle Internet Directory-ODS, Oracle Identity Analytics Architecture-OIA Statistics