PageLog
Transaction log mechanism. The stream contains a list of records. The data
format for a record is:
- type (0: no-op, 1: undo, 2: commit, ...)
- data
The transaction log is split into sections.
A checkpoint starts a new section.
| Methods |
|---|
| static Row |
readRow(RowFactory rowFactory, DataReader in, Data data)
Read a row from an input stream.
|
| static Row |
readRow(RowFactory rowFactory, DataReader in, Data data) throws IOException
Read a row from an input stream.
Parameters:
rowFactory - the row factory
in - the input stream
data - a temporary buffer
Returns:
the row
|
| void |
addUndo(int pageId, Data page)
Add an undo entry to the log.
|
| void |
addUndo(int pageId, Data page)
Add an undo entry to the log. The page data is only written once until
the next checkpoint.
Parameters:
pageId - the page id
page - the old page data
|
| void |
checkpoint()
Switch to a new log section.
|
| void |
checkpoint()
Switch to a new log section.
|
| void |
close()
Close without further writing.
|
| void |
close()
Close without further writing.
|
| void |
commit(int sessionId)
Mark a transaction as committed.
|
| void |
commit(int sessionId)
Mark a transaction as committed.
Parameters:
sessionId - the session
|
| void |
flush()
Flush the transaction log.
|
| void |
flush()
Flush the transaction log.
|
| void |
free()
Free up all pages allocated by the log.
|
| void |
free()
Free up all pages allocated by the log.
|
| ArrayList |
getInDoubtTransactions()
|
| ArrayList |
getInDoubtTransactions()
|
| int |
getLogFirstSectionId()
|
| int |
getLogFirstSectionId()
|
| int |
getLogPos()
|
| int |
getLogPos()
|
| int |
getLogSectionId()
|
| int |
getLogSectionId()
|
| int |
getMinPageId()
Get the smallest possible page id used.
|
| int |
getMinPageId()
Get the smallest possible page id used. This is the trunk page if only
appending at the end of the file, or 0.
Returns:
the smallest possible page.
|
| long |
getSize()
|
| long |
getSize()
|
| boolean |
getUndo(int pageId)
Check if the undo entry was already written for the given page.
|
| boolean |
getUndo(int pageId)
Check if the undo entry was already written for the given page.
Parameters:
pageId - the page
Returns:
true if it was written
|
| void |
logAddOrRemoveRow(Session session, int tableId, Row row, boolean add)
A record is added to a table, or removed from a table.
|
| void |
logAddOrRemoveRow(Session session, int tableId, Row row, boolean add)
A record is added to a table, or removed from a table.
Parameters:
session - the session
tableId - the table id
row - the row to add
add - true if the row is added, false if it is removed
|
| void |
logTruncate(Session session, int tableId)
A table is truncated.
|
| void |
logTruncate(Session session, int tableId)
A table is truncated.
Parameters:
session - the session
tableId - the table id
|
| void |
openForReading(int newLogKey, int newFirstTrunkPage, int newFirstDataPage)
Open the log for reading.
|
| void |
openForReading(int newLogKey, int newFirstTrunkPage, int newFirstDataPage)
Open the log for reading.
Parameters:
newLogKey - the first expected log key
newFirstTrunkPage - the first trunk page
newFirstDataPage - the index of the first data page
|
| void |
openForWriting(int newFirstTrunkPage, boolean atEnd)
Open the log for writing.
|
| void |
openForWriting(int newFirstTrunkPage, boolean atEnd)
Open the log for writing. For an existing database, the recovery
must be run first.
Parameters:
newFirstTrunkPage - the first trunk page
atEnd - whether only pages at the end of the file should be used
|
| void |
prepareCommit(Session session, String transaction)
Prepare a transaction.
|
| void |
prepareCommit(Session session, String transaction)
Prepare a transaction.
Parameters:
session - the session
transaction - the name of the transaction
|
| boolean |
recover(int stage)
Run one recovery stage.
|
| boolean |
recover(int stage)
Run one recovery stage. There are three recovery stages: 0: only the undo
steps are run (restoring the state before the last checkpoint). 1: the
pages that are used by the transaction log are allocated. 2: the
committed operations are re-applied.
Parameters:
stage - the recovery stage
Returns:
whether the transaction log was empty
|
| void |
recoverEnd()
Called after the recovery has been completed.
|
| void |
recoverEnd()
Called after the recovery has been completed.
|
| void |
removeUntil(int firstUncommittedSection)
Remove all pages until the given log (excluding).
|
| void |
removeUntil(int firstUncommittedSection)
Remove all pages until the given log (excluding).
Parameters:
firstUncommittedSection - the first log section to keep
|
| void |
setInDoubtTransactionState(int sessionId, int pageId, boolean commit)
Set the state of an in-doubt transaction.
|
| void |
setInDoubtTransactionState(int sessionId, int pageId, boolean commit)
Set the state of an in-doubt transaction.
Parameters:
sessionId - the session
pageId - the page where the commit was prepared
commit - whether the transaction should be committed
|
NOOP
= 0
No operation.
RECOVERY_STAGE_UNDO
= 0
The recovery stage to undo changes (re-apply the backup).
RECOVERY_STAGE_ALLOCATE
= 1
The recovery stage to allocate pages used by the transaction log.
UNDO
= 1
An undo log entry. Format: page id: varInt, size, page. Size 0 means
uncompressed, size 1 means empty page, otherwise the size is the number
of compressed bytes.
COMMIT
= 2
A commit entry of a session.
Format: session id: varInt.
RECOVERY_STAGE_REDO
= 2
The recovery stage to redo operations.
PREPARE_COMMIT
= 3
A prepare commit entry for a session.
Format: session id: varInt, transaction name: string.
ROLLBACK
= 4
Roll back a prepared transaction.
Format: session id: varInt.
ADD
= 5
Add a record to a table.
Format: session id: varInt, table id: varInt, row.
REMOVE
= 6
Remove a record from a table.
Format: session id: varInt, table id: varInt, row.
TRUNCATE
= 7
Truncate a table.
Format: session id: varInt, table id: varInt.
CHECKPOINT
= 8
Perform a checkpoint. The log section id is incremented.
Format: -
FREE_LOG
= 9
Free a log page.
Format: count: varInt, page ids: varInt