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org.apache.derby.iapi.store.raw
Interface ContainerHandle  

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public interface ContainerHandle

A Container contains a contigious address space of pages, the pages start at page number Container.FIRST_PAGE_NUMBER and are numbered sequentially. The page size is set at addContainer() time. RESOLVE: this style of coding is not currently enforced If the caller calls getPage (or one of its variants) more than once on the same page, the caller must call unlatch a corresponding number of times in order to ensure that the page is latched. For example:

    Container c;
        Page p1 = c.getPage(Container.FIRST_PAGE_NUMBER);
        Page p2 = c.getPage(Container.FIRST_PAGE_NUMBER);
        p1.unlatch();  -- Page is still latched.
        p2.unlatch();  -- Page is now unlatched.
        

There is no restriction on the order in which latching and unlatching is done. In the example, p1 could have been unlatched after p2 with no ill effects.

Open container modes ContainerHandle.MODE are used to open or create the container. Unlike TableProperties, MODEs are not permanantely associated with the container, it is effective only for the lifetime of the containerHandle itself.
A container may use any of these mode flags when it is opened.

• MODE_READONLY - Open the container in read only mode.
• MODE_FORUPDATE - Open the container in update mode, if the underlying storage does not allow updates then the container will be opned in read only mode.
• MODE_UNLOGGED - If Unset, any changes to the container are logged. If set, any user changes to the container are unlogged. It is guaranteed at commit time that all changes made during the transaction will have been flushed to disk. Using this mode automatically opens the container in container locking, isolation 3 level. The state of the container following an abort or any type of rollback is unspecified.
• MODE_CREATE_UNLOGGED - If set, not only are user changes to the container are unlogged, page allocations are also unlogged. This MODE is only useful for container is created in the same statement and no change on the container (other than the create) is ever logged. The difference between MODE_UNLOGGED and MODE_CREATE_UNLOGGED is that page allocation is also unlogged and commit of nested transaction will not cause the container to be forced from the cache. Unlike MODE_UNLOGGED, MODE_CREATE_UNLOGGED does not force the cache. It is up to the client of raw store to force the cache at the appropriate time - this allows a statement to create and open the container serveral times for bulk loading without logging or doing any synchronous I/O.
• MODE_LOCK_NOWAIT - if set, then don't wait for the container lock, else wait for the container lock. This flag only dictates whether the lock should be waited for or not. After the container is successfully opened, whether this bit is set or not has no effect on the container handle.

If neither or both of the {MODE_READONLY, MODE_FORUPDATE} modes are specified then the behaviour of the container is unspecified.
MODE_UNLOGGED must be set for MODE_CREATE_UNLOGGED to be set.

Temporary Containers
If when creating a container the segment used is ContainerHandle.TEMPORARY_SEGMENT then the container is a temporary container. Temporary containers are not logged or locked and do not live across re-boots of the system. In addition any abort or rollback including rollbacks to savepoints truncate the container if it has been opened for update since the last commit or abort. Temporary containers are private to a transaction and must only be used a single thread within the transaction at any time, these restrictions are not currently enforced.
When opening a temporary container for update access these additional mode flags may be used

• MODE_TRUNCATE_ON_COMMIT - At commit/abort time container is truncated.
• MODE_DROP_ON_COMMIT - At commit/abort time the container is dropped.
• MODE_TEMP_IS_KEPT - At commit/abort time the container is kept around.

If a temporary container is opened multiple times in the same transaction with different modes then the most severe mode is used, ie. none < truncate on commit < drop on commit. The MODE_UNLOGGED, MODE_CREAT_UNLOGGED flags are ignored when opening a temporary container, not logged is always assumed.

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Field Summary
static int	ADD_PAGE_BULK
static int	ADD_PAGE_DEFAULT
static int	DEFAULT_ASSIGN_ID
static int	DEFAULT_PAGESIZE           Used in add container.
static int	DEFAULT_SPARESPACE
static long	FIRST_PAGE_NUMBER           The first valid page number
static int	GET_PAGE_UNFILLED
static long	INVALID_PAGE_NUMBER           A page number that is guaranteed to be invalid.
static int	MODE_BASEROW_INSERT_LOCKED
static int	MODE_CREATE_UNLOGGED
static int	MODE_DEFAULT           See comments above for these modes.
static int	MODE_DROP_ON_COMMIT
static int	MODE_FLUSH_ON_COMMIT
static int	MODE_FORUPDATE
static int	MODE_LOCK_NOWAIT
static int	MODE_NO_ACTIONS_ON_COMMIT
static int	MODE_OPEN_FOR_LOCK_ONLY
static int	MODE_READONLY
static int	MODE_SECONDARY_LOCKED
static int	MODE_TEMP_IS_KEPT
static int	MODE_TRUNCATE_ON_COMMIT
static int	MODE_TRUNCATE_ON_ROLLBACK
static int	MODE_UNLOGGED
static int	MODE_USE_UPDATE_LOCKS
static int	TEMPORARY_SEGMENT

 

Method Summary
Page	addPage()           Add an empty page to the container and obtain exclusive access to it.
Page	addPage(int flag)           Add an empty page to the container and obtain exclusive access to it.
void	close()           Close me.
void	compactRecord(RecordHandle record)           This record probably has shrunk considerably.
void	compressContainer()           Release free space to the OS.
void	flushContainer()           Flush all dirty pages of the container to disk.
void	getContainerProperties(java.util.Properties prop)           Request the system properties associated with a container.
long	getEstimatedPageCount(int flag)           Get the total estimated number of allocated (not freed, not deallocated) user pages in the container, including overflow pages.
long	getEstimatedRowCount(int flag)           Get the total estimated number of rows in the container, not including overflow rows.
Page	getFirstPage()           Obtain exclusive access to the current first page of the container.
ContainerKey	getId()           Return my identifier.
LockingPolicy	getLockingPolicy()           Return the locking policy for this open container.
Page	getNextPage(long prevNum)           Obtain exclusive access to the next valid page of the given page number in the container.
Page	getPage(long pageNumber)           Obtain exclusive access to the page with the given page number.
Page	getPageForCompress(int flag, long pageno)
Page	getPageForInsert(int flag)           Get a page for insert.
Page	getPageNoWait(long pageNumber)           Identical to getPage but returns null immediately if the desired page is already latched by another Container.
org.apache.derby.iapi.store.access.SpaceInfo	getSpaceInfo()           Get information about space used by the container.
java.lang.Object	getUniqueId()           Return my unique identifier, this identifier will be unique to each instance of an open container handle.
Page	getUserPageNoWait(long pageNumber)           Obtain exclusive access to the page with the given page number.
Page	getUserPageWait(long pageNumber)           Obtain exclusive access to the page with the given page number.
boolean	isReadOnly()           Is the container opened for read only or update?
boolean	isTemporaryContainer()           Return true if this containerHandle refers to a temporary container.
RecordHandle	makeRecordHandle(long pageNumber, int recordId)           Return a record handle that is initialized to the given segment id, container id, page number and record id.
void	preAllocate(int numPage)           Try to preallocate numPage new pages if possible.
void	removePage(Page page)           Remove this page from the container and unlatch the page.
void	setEstimatedRowCount(long count, int flag)           Set the total estimated number of rows in the container.
void	setLockingPolicy(LockingPolicy newLockingPolicy)           Set the locking policy for this open container

 

Field Detail

DEFAULT_PAGESIZE

public static final int DEFAULT_PAGESIZE

Used in add container.

See Also:

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DEFAULT_SPARESPACE

public static final int DEFAULT_SPARESPACE

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DEFAULT_ASSIGN_ID

public static final int DEFAULT_ASSIGN_ID

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MODE_DEFAULT

public static final int MODE_DEFAULT

See comments above for these modes.

See Also:

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MODE_UNLOGGED

public static final int MODE_UNLOGGED

See Also:

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MODE_CREATE_UNLOGGED

public static final int MODE_CREATE_UNLOGGED

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MODE_FORUPDATE

public static final int MODE_FORUPDATE

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MODE_READONLY

public static final int MODE_READONLY

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MODE_TRUNCATE_ON_COMMIT

public static final int MODE_TRUNCATE_ON_COMMIT

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MODE_DROP_ON_COMMIT

public static final int MODE_DROP_ON_COMMIT

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MODE_OPEN_FOR_LOCK_ONLY

public static final int MODE_OPEN_FOR_LOCK_ONLY

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MODE_LOCK_NOWAIT

public static final int MODE_LOCK_NOWAIT

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MODE_TRUNCATE_ON_ROLLBACK

public static final int MODE_TRUNCATE_ON_ROLLBACK

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MODE_FLUSH_ON_COMMIT

public static final int MODE_FLUSH_ON_COMMIT

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MODE_NO_ACTIONS_ON_COMMIT

public static final int MODE_NO_ACTIONS_ON_COMMIT

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MODE_TEMP_IS_KEPT

public static final int MODE_TEMP_IS_KEPT

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MODE_USE_UPDATE_LOCKS

public static final int MODE_USE_UPDATE_LOCKS

See Also:

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MODE_SECONDARY_LOCKED

public static final int MODE_SECONDARY_LOCKED

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MODE_BASEROW_INSERT_LOCKED

public static final int MODE_BASEROW_INSERT_LOCKED

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TEMPORARY_SEGMENT

public static final int TEMPORARY_SEGMENT

See Also:

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FIRST_PAGE_NUMBER

public static final long FIRST_PAGE_NUMBER

The first valid page number

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INVALID_PAGE_NUMBER

public static final long INVALID_PAGE_NUMBER

A page number that is guaranteed to be invalid.

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ADD_PAGE_DEFAULT

public static final int ADD_PAGE_DEFAULT

See Also:

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ADD_PAGE_BULK

public static final int ADD_PAGE_BULK

See Also:

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GET_PAGE_UNFILLED

public static final int GET_PAGE_UNFILLED

See Also:

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Method Detail

getId

public ContainerKey getId()

Return my identifier.

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getUniqueId

public java.lang.Object getUniqueId()

Return my unique identifier, this identifier will be unique to each instance of an open container handle. This id is used by the locking system to group locks to an open container handle.

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isReadOnly

public boolean isReadOnly()

Is the container opened for read only or update?

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addPage

public Page addPage()
             throws org.apache.derby.iapi.error.StandardException

Add an empty page to the container and obtain exclusive access to it.

Note that the added page may not be the last page in the Container. Once the Page is no longer required the Page's unlatch() method must be called.

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compressContainer

public void compressContainer()
                       throws org.apache.derby.iapi.error.StandardException

Release free space to the OS.

As is possible release any free space to the operating system. This will usually mean releasing any free pages located at the end of the file using the java truncate() interface.

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addPage

public Page addPage(int flag)
             throws org.apache.derby.iapi.error.StandardException

Add an empty page to the container and obtain exclusive access to it.

If flag == ADD_PAGE_DEFAULT, this call is identical to addPage().
If flag == ADD_PAGE_BULK, then this call signifies to the container that this addPage is part of a large number of additional pages and it is desirable to do whatever possible to facilitate adding many subsequent pages. The actual container implementation will decide whether or not to heed this hint and what to do about it.

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preAllocate

public void preAllocate(int numPage)

Try to preallocate numPage new pages if possible.

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removePage

public void removePage(Page page)
                throws org.apache.derby.iapi.error.StandardException

Remove this page from the container and unlatch the page. Caller should commit or abort this transaction ASAP because failure to do so will slow down page allocation of this container.
The page to be removed must be latched and gotten (or added) by this ContainerHandle. The page should not be used again after this call as if it has been unlatched. If the call to removePage is successful, this page is invalid should not be gotten again with getPage.
RemovePage will guarantee to unlatch the page even if a StandardException is thrown.

Locking Policy
The page will not be freed until the transaction that removed the page commits. A special RecordHandle.DEALLOC_PROTECTION_HANDLE lock will be gotten for the transaction and which is used to prevent the page from being freed. This lock will be held regardless of the default locking policy of the transaction that called removedPage.

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getPage

public Page getPage(long pageNumber)
             throws org.apache.derby.iapi.error.StandardException

Obtain exclusive access to the page with the given page number. Once the Page is no longer required the Page's unlatch() method must be called.

The Page object is guaranteed to remain in-memory and exclusive to the caller until its unlatch() method is called.

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getPageNoWait

public Page getPageNoWait(long pageNumber)
                   throws org.apache.derby.iapi.error.StandardException

Identical to getPage but returns null immediately if the desired page is already latched by another Container.

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getUserPageNoWait

public Page getUserPageNoWait(long pageNumber)
                       throws org.apache.derby.iapi.error.StandardException

Obtain exclusive access to the page with the given page number. Will only return a valid, non-overflow user page - so can be used by routines in post commit to get pages to attempt deleted row space reclamation. If for some reason a request is made for an overflow page a null will be returned. Once the Page is no longer required the Page's unlatch() method must be called.

The Page object is guaranteed to remain in-memory and exclusive to the caller until its unlatch() method is called.

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getUserPageWait

public Page getUserPageWait(long pageNumber)
                     throws org.apache.derby.iapi.error.StandardException

Obtain exclusive access to the page with the given page number. Will only return a valid, non-overflow user page - so can be used by routines in post commit to get pages to attempt deleted row space reclamation. If for some reason a request is made for an overflow page a null will be returned. Once the Page is no longer required the Page's unlatch() method must be called.

The Page object is guaranteed to remain in-memory and exclusive to the caller until its unlatch() method is called.

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getFirstPage

public Page getFirstPage()
                  throws org.apache.derby.iapi.error.StandardException

Obtain exclusive access to the current first page of the container. Only a valid, non overflow page will be returned. Pages in the container are ordered in an internally defined ordering.

Note that once this method returns this page may no longer be the first page of the container. I.e, other threads may allocate pages prior to this page number while this page is latched. It is up to the caller of this routine to synchronize this call with addPage to assure that this is the first page.
As long as the client provide the necessary lock to ensure that no addPage is called, then this page is guaranteed to be the first page of the container in some internally defined ordering of the pages.

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getNextPage

public Page getNextPage(long prevNum)
                 throws org.apache.derby.iapi.error.StandardException

Obtain exclusive access to the next valid page of the given page number in the container. Only a valid, non overflow page will be returned. Pages in the container are ordered in an internally defined ordering.

Note that once this method returns this page may no longer be the next page of the container. I.e, other threads may allocate pages prior to this page number while this page is latched. It is up to the caller of this routine to synchronize this call with addPage to assure that this is the first page.
As long as the client provide the necessary lock to ensure that no addPage is called, then this page is guaranteed to be the next page of the container in some internally defined ordering of the pages.
If no pages are added or removed, then an iteration such as:

                for (Page p = containerHandle.getFirstPage();
                         p != null;
                         p = containerHandle.getNextPage(p.getPageNumber()))
                
                will guarentee to iterate thru and latched all the valid pages 
                in the container

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getPageForInsert

public Page getPageForInsert(int flag)
                      throws org.apache.derby.iapi.error.StandardException

Get a page for insert. If RawStore thinks it knows where a potentially suitable page is for insert, it will return it. If RawStore doesn't know where a suitable page for insert is, or if there are no allocated page, then null is returned. If a page is returned, it will be a valid, non-overflow page. A potentially suitable page is one which has enough space for a minium sized record.

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getPageForCompress

public Page getPageForCompress(int flag,
                               long pageno)
                        throws org.apache.derby.iapi.error.StandardException

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getContainerProperties

public void getContainerProperties(java.util.Properties prop)
                            throws org.apache.derby.iapi.error.StandardException

Request the system properties associated with a container.

Request the value of properties that are associated with a table. The following properties can be requested: derby.storage.pageSize derby.storage.pageReservedSpace derby.storage.minimumRecordSize

To get the value of a particular property add it to the property list, and on return the value of the property will be set to it's current value. For example: get_prop(ConglomerateController cc) { Properties prop = new Properties(); prop.put("derby.storage.pageSize", ""); cc.getTableProperties(prop); System.out.println( "table's page size = " + prop.getProperty("derby.storage.pageSize"); }

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close

public void close()

Close me. After using this method the caller must throw away the reference to the Container object, e.g.

                        ref.close();
                        ref = null;
                

The container will be closed automatically at the commit or abort of the transaction if this method is not called explictly.
Any pages that were obtained using me and have not been released using Page's unlatch method are released, and references to them must be thrown away.

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getEstimatedRowCount

public long getEstimatedRowCount(int flag)
                          throws org.apache.derby.iapi.error.StandardException

Get the total estimated number of rows in the container, not including overflow rows. This number is a rough estimate and may be grossly off.

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setEstimatedRowCount

public void setEstimatedRowCount(long count,
                                 int flag)
                          throws org.apache.derby.iapi.error.StandardException

Set the total estimated number of rows in the container. Often, after a scan, the client of RawStore has a much better estimate of the number of rows in the container then what RawStore has. Use this better number for future reference.
It is OK for a ReadOnly ContainerHandle to set the estimated row count.

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getEstimatedPageCount

public long getEstimatedPageCount(int flag)
                           throws org.apache.derby.iapi.error.StandardException

Get the total estimated number of allocated (not freed, not deallocated) user pages in the container, including overflow pages. this number is a rough estimate and may be grossly off.

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flushContainer

public void flushContainer()
                    throws org.apache.derby.iapi.error.StandardException

Flush all dirty pages of the container to disk. Used mainly for UNLOGGED or CREATE_UNLOGGED operation.

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getLockingPolicy

public LockingPolicy getLockingPolicy()

Return the locking policy for this open container.

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setLockingPolicy

public void setLockingPolicy(LockingPolicy newLockingPolicy)

Set the locking policy for this open container

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makeRecordHandle

public RecordHandle makeRecordHandle(long pageNumber,
                                     int recordId)
                              throws org.apache.derby.iapi.error.StandardException

Return a record handle that is initialized to the given segment id, container id, page number and record id.

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compactRecord

public void compactRecord(RecordHandle record)
                   throws org.apache.derby.iapi.error.StandardException

This record probably has shrunk considerably. Free its reserved space or compact it.

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isTemporaryContainer

public boolean isTemporaryContainer()
                             throws org.apache.derby.iapi.error.StandardException

Return true if this containerHandle refers to a temporary container.

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getSpaceInfo

public org.apache.derby.iapi.store.access.SpaceInfo getSpaceInfo()
                                                          throws org.apache.derby.iapi.error.StandardException

Get information about space used by the container.

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> iapi >> store >> [ raw overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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