pack-priv Class RAFContainer

Implements abstract org.apache.derby.impl.store.raw.data.FileContainer.backupContainer.

Backup the container. The container is written to the backup by reading the pages through the page cache, and then writing into the backup container. If the container is dropped(commitetd drop), only container stub is copied to the backup using simple file copy. MT - At any given time only one backup thread is allowed, but when backup in progress DML/DDL operations can run in parallel. Pages are latched while writing them to the backup to avoid copying partial changes to the pages. Online backup does not acquire any user level locks , so users can drop tables when backup is in progress. So it is possible that Container Removal request can come in when container backup is in progress. This case is handled by using the synchronization on this object monitor and using inRemove and inBackup flags. Conatiner removal checks if backup is in progress and wait for the backup to yield to continue the removal. Basic idea is to give preference to remove by stopping the backup of the container temporarily, when the remove container is requested by another thread. Generally, it takes more time to backup a regular container than the stub becuase stub is just one page. After each page copy, a check is made to find if a remove is requested and if it is then backup of the container is aborted and the backup thread puts itself into the wait state until remove request thread notifies that the remove is complete. When remove request compeletes stub is copied into the backup. Compress is blocked when backup is in progesss, so truncation of the container can not happen when backup is in progess. No need to synchronize backup of the container with truncation.

Parameters

handle:BaseContainerHandle

the container handle.

backupLocation:String

location of the backup container.

Exceptions

StandardException:

Derby Standard error policy

Implements abstract org.apache.derby.impl.store.raw.data.BaseContainer.encryptOrDecryptContainer.

Creates encrypted or decrypted version of the container. Reads all the pages of the container from the original container through the page cache, then either encrypts page data with the new encryption mechanism or leaves the page data un-encrypted, and finally writes the data to the specified new container file.

The encryption and decryption engines used to carry out the cryptographic operation(s) are configured through the raw store, and accessed via the data factory. Note that the pages have already been decrypted before being put into the page cache.

Parameters

handle:BaseContainerHandle

the container handle

newFilePath:String

file to store the new version of the container in

doEncrypt:boolean

tells whether to encrypt or not

Exceptions

StandardException:

Derby Standard error policy

Implements abstract org.apache.derby.impl.store.raw.data.BaseContainer.flushAll.

flush the cache to ensure all of my pages are written to disk

Exceptions

StandardException:

Standard Derby error policy

Implements abstract org.apache.derby.impl.store.raw.data.FileContainer.preAllocate.

Preallocate some pages if need be

Parameters

lastPreallocPagenum:long

Doc from org.apache.derby.impl.store.raw.data.FileContainer.preAllocate.

the last preallocated page number as known by the allocation page

preAllocSize:int

Doc from org.apache.derby.impl.store.raw.data.FileContainer.preAllocate.

try to preallocate this page number of pages. Since only the container knows how many pages are actually on disk, it may determine that certain number of pages that the allocation page thinks need to be preallocated is already allocated, in those case, act as if the preallocation is successful.

Returns:int

Doc from org.apache.derby.impl.store.raw.data.FileContainer.preAllocate.

number of successfully preallocated page, or 0 if no page has been preallocated

Implements abstract org.apache.derby.impl.store.raw.data.FileContainer.readPage.

Read a page into the supplied array.
MT - thread safe

Exceptions

IOException:

exception reading page

StandardException:

Standard Derby error policy

Implements abstract org.apache.derby.impl.store.raw.data.BaseContainer.removeContainer.

Remove the container

Parameters

leaveStub:boolean

Doc from org.apache.derby.impl.store.raw.data.BaseContainer.removeContainer.

if true, leave a stub. If false, remove everything

Exceptions

StandardException:

Standard Derby error policy

Only used by RAFContainer4 (NIO) to reopen RAF when its channel gets closed due to interrupts.

Exceptions

StandardException:

standard exception policy

Implements abstract org.apache.derby.impl.store.raw.data.BaseContainer.truncatePages.

Truncate pages of a container.

Truncate all pages from lastValidPagenum+1 through the end of the file.

Parameters

lastValidPagenum:long

The page number of the last valid page of the file. All pages after this one are truncated.

Exceptions

StandardException:

Standard exception policy.

Updates the page array with container header if the page is a first allocation page and encrypts the page data if the database is encrypted.

Parameters

pageNumber:long

the page number of the page

pageData:byte[]

byte array that has the actual page data.

encryptionBuf:byte[]

buffer that is used to store encrypted version of the page, or null if encryption is to be skipped

encryptWithNewEngine:boolean

whether to use the new encryption engine for encryption (only considered if encryptionBuf != null)

Returns:byte[]

byte array of the the page data as it should be on the disk.

Implements abstract org.apache.derby.impl.store.raw.data.FileContainer.writePage.

Write a page from the supplied array.
MT - thread safe

Exceptions

IOException:

IO error accessing page

StandardException:

Standard Derby error policy