Class LUWBufferPool {Analysis} derived from: SQLObject

Documentation
DB2 Universal Database SQL Reference Version 8.1 (Vol.1 and 2)
http://www7b.software.ibm.com/dmdd/library/techarticle/0206sqlref/0206sqlref.html

Table spaces and other storage structures

Storage structures contain database objects. The basic storage structure is the table space; it contains tables, indexes, large objects, and data defined with a LONG data type.

There are two types of table spaces:
- Database managed space (DMS): a table space that is managed by the database manager.
- System managed space (SMS): a table space that is managed by the operating system.

All table spaces consist of containers. A container describes where objects are stored. A subdirectory in a file system is an example of a container.

When data is read from table space containers, it is placed in an area of memory called a buffer pool. A buffer pool is associated with a specific table space, thereby allowing control over which data will share the same memory areas for data buffering.


NUMBLOCKPAGES number-of-pages:
Specifies the number of pages that should exist in the block-based area. The number of pages must not be greater than 98 percent of the number of pages for the buffer pool (SQLSTATE 54052). Specifying the value 0 disables block I/O. The actual value of NUMBLOCKPAGES used will be a multiple of BLOCKSIZE.

BLOCKSIZE number-of-pages:
Specifies the number of pages in a block. The block size must be a value between 2 and 256 (SQLSTATE 54053). The default value is 32.

PAGESIZE integer [K]:
Defines the size of pages used for the bufferpool. The valid values for integer without the suffix K are 4 096, 8 192, 16 384 or 32 768. The valid values for integer with the suffix K are 4, 8, 16 or 32. An error occurs if the page size is not one of these values (SQLSTATE 428DE). The default is 4 096 byte (4K) pages. Any number of spaces is allowed between integer and K, including no space.

EXTENDED STORAGE
If extended storage is enabled, pages that are being evicted from this buffer pool will be cached in extended storage. (Extended storage is enabled by setting the database configuration parameters NUM_ESTORE_SEGS and ESTORE_SEG_SIZE to non-zero values.)

NOT EXTENDED STORAGE
Even if extended storage is enabled, pages that are being evicted from this buffer pool are not cached in extended storage.

Notes:
Compatibilities: for compatibility with previous versions of DB2:
- NODE can be specified in place of DBPARTITIONNUM
- NODES can be specified in place of DBPARTITIONNUMS
- NODEGROUP can be specified in place of DATABASE PARTITION GROUP

- If the buffer pool is created using the DEFERRED option, any table space created in this buffer pool will use a small system buffer pool of the same page size, until next database activation. The database has to be restarted for the buffer pool to become active and for table space assignments to the new buffer pool to take effect. The default option is IMMEDIATE.
- A buffer pool cannot be created with both extended storage and block-based support.
- There should be enough real memory on the machine for the total of all the buffer pools, as well as for the rest of the database manager and application requirements. If DB2 is unable to obtain memory for the regular buffer pools, it will attempt to start up with small system buffer pools, one for each page size (4K, 8K, 16K and 32K). In this situation, a warning will be returned to the user (SQLSTATE 01626), and the pages from all table spaces will use the system buffer pools.


Parent PackageLUWAbstractNo
Export ControlPublicAccessLink Class forNone
Class KindNormalClassCardinalityn
Space ConcurrencySequential
PersistenceNo  


Operations
NameSignatureClass
addEAnnotationEAnnotation addEAnnotation (String source)SQLObject
addEAnnotationDetailvoid addEAnnotationDetail (EAnnotation eAnnotation, String key, String value)SQLObject
getEAnnotationDetailString getEAnnotationDetail (EAnnotation eAnnotation, String key)SQLObject
setAnnotationDetailvoid setAnnotationDetail (EAnnotation eAnnotation, String key, String value)SQLObject
removeEAnnotationDetailvoid removeEAnnotationDetail (EAnnotation eAnnotation, String key)SQLObject
getEAnnotationEAnnotation getEAnnotation (String source)SQLObject
getEAnnotationEAnnotation getEAnnotation (String source)EModelElement
eClassEClass eClass ()EObject
eIsProxyboolean eIsProxy ()EObject
eResourceEResource eResource ()EObject
eContainerEObject eContainer ()EObject
eContainingFeatureEStructuralFeature eContainingFeature ()EObject
eContainmentFeatureEReference eContainmentFeature ()EObject
eContentsEEList eContents ()EObject
eAllContentsETreeIterator eAllContents ()EObject
eCrossReferencesEEList eCrossReferences ()EObject
eGetEJavaObject eGet (EStructuralFeature feature)EObject
eGetEJavaObject eGet (EStructuralFeature feature, boolean resolve)EObject
eSet eSet (EStructuralFeature feature, EJavaObject newValue)EObject
eIsSetboolean eIsSet (EStructuralFeature feature)EObject
eUnset eUnset (EStructuralFeature feature)EObject


Attributes
NameClassTypeInitial Value
createTypeLUWBufferPoolBufferPoolType 
sizeLUWBufferPoolint 
pageSizeLUWBufferPoolPageSizeTypeFOUR_K
blockSizeLUWBufferPoolint32
numBlockPagesLUWBufferPoolint 
extendedStorageLUWBufferPoolboolean 
automaticLUWBufferPoolbooleantrue
descriptionSQLObjectString 
labelSQLObjectString 
nameENamedElementString 


Associations
NameMy RoleMy ClassOther RoleOther Element
--Not Named--bufferPoolLUWBufferPooltableSpacesLUWTableSpace
--Not Named--bufferPoolLUWBufferPoolpartitionsLUWDatabasePartition
--Not Named--bufferPoolLUWBufferPoolpartitionGroupLUWPartitionGroup
--Not Named--bufferpoolsLUWBufferPooldatabaseLUWDatabase
--Not Named----Not Named--SQLObjectcommentsComment
=--Not Named--SQLObjectdependenciesDependency
--Not Named--objectSQLObjectprivilegesPrivilege
--Not Named--actionObjectsSQLObject--Not Named--Privilege
--Not Named--eModelElementEModelElementeAnnotationsEAnnotation
--Not Named--contentsEObject--Not Named--EAnnotation
--Not Named--referencesEObject--Not Named--EAnnotation
--Not Named--targetEndEObject--Not Named--Dependency


Generalization Relationships
NameClassSupplier
--Not Named--LUWBufferPoolSQLObject
--Not Named--SQLObjectENamedElement
--Not Named--ENamedElementEModelElement
--Not Named--EModelElementEObject



Property Settings

Data Modeler
dmItemFalseDMName 
IsTableFalseIsViewFalse
IsDomainFalseIsSPPackageFalse
Synonymns TableSpaceID 
SourceId SourceType 
CorrelationName SelectClause 
IsUpdateableTrueCheckOptionNone
IsSnapShotFalseIsDistinctFalse
PersistToServer IsPackageFalse