public class FileTxnLog extends Object implements TxnLog, Closeable
The format of a Transactional log is as follows:
LogFile: FileHeader TxnList ZeroPad FileHeader: { magic 4bytes (ZKLG) version 4bytes dbid 8bytes } TxnList: Txn || Txn TxnList Txn: checksum Txnlen TxnHeader Record 0x42 checksum: 8bytes Adler32 is currently used calculated across payload -- Txnlen, TxnHeader, Record and 0x42 Txnlen: len 4bytes TxnHeader: { sessionid 8bytes cxid 4bytes zxid 8bytes time 8bytes type 4bytes } Record: See Jute definition file for details on the various record types ZeroPad: 0 padded to EOF (filled during preallocation stage)
Modifier and Type | Class and Description |
---|---|
static class |
FileTxnLog.FileTxnIterator
this class implements the txnlog iterator interface
which is used for reading the transaction logs
|
TxnLog.TxnIterator
Modifier and Type | Field and Description |
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static String |
LOG_FILE_PREFIX |
static int |
TXNLOG_MAGIC |
static int |
VERSION |
Constructor and Description |
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FileTxnLog(File logDir)
constructor for FileTxnLog.
|
Modifier and Type | Method and Description |
---|---|
boolean |
append(TxnHeader hdr,
Record txn)
append an entry to the transaction log
|
boolean |
append(TxnHeader hdr,
Record txn,
TxnDigest digest)
Append a request to the transaction log with a digset
|
void |
close()
close all the open file handles
|
void |
commit()
commit the logs.
|
long |
getCurrentLogSize()
Return the current on-disk size of log size.
|
long |
getDbId()
the dbid of this transaction database
|
long |
getLastLoggedZxid()
get the last zxid that was logged in the transaction logs
|
static File[] |
getLogFiles(File[] logDirList,
long snapshotZxid)
Find the log file that starts at, or just before, the snapshot.
|
long |
getTotalLogSize()
Gets the total size of all log files
|
long |
getTxnLogSyncElapsedTime() |
boolean |
isForceSync()
the forceSync value.
|
protected Checksum |
makeChecksumAlgorithm()
creates a checksum algorithm to be used
|
TxnLog.TxnIterator |
read(long zxid)
start reading all the transactions from the given zxid
|
TxnLog.TxnIterator |
read(long zxid,
boolean fastForward)
start reading all the transactions from the given zxid.
|
void |
rollLog()
rollover the current log file to a new one.
|
static void |
setPreallocSize(long size)
method to allow setting preallocate size
of log file to pad the file.
|
void |
setServerStats(ServerStats serverStats)
Setter for ServerStats to monitor fsync threshold exceed
|
void |
setTotalLogSize(long size)
Sets the total size of all log files
|
static void |
setTxnLogSizeLimit(long size)
Set log size limit
|
boolean |
truncate(long zxid)
truncate the current transaction logs
|
public static final int TXNLOG_MAGIC
public static final int VERSION
public static final String LOG_FILE_PREFIX
public FileTxnLog(File logDir)
logDir
- the directory where the txnlogs are storedpublic static void setPreallocSize(long size)
size
- the size to set to in bytespublic void setServerStats(ServerStats serverStats)
setServerStats
in interface TxnLog
serverStats
- used to update fsyncThresholdExceedCountpublic static void setTxnLogSizeLimit(long size)
public long getCurrentLogSize()
public void setTotalLogSize(long size)
TxnLog
setTotalLogSize
in interface TxnLog
public long getTotalLogSize()
TxnLog
getTotalLogSize
in interface TxnLog
protected Checksum makeChecksumAlgorithm()
public void rollLog() throws IOException
rollLog
in interface TxnLog
IOException
public void close() throws IOException
close
in interface Closeable
close
in interface AutoCloseable
close
in interface TxnLog
IOException
public boolean append(TxnHeader hdr, Record txn) throws IOException
append
in interface TxnLog
hdr
- the header of the transactiontxn
- the transaction part of the entry
returns true iff something appended, otw falseIOException
public boolean append(TxnHeader hdr, Record txn, TxnDigest digest) throws IOException
TxnLog
append
in interface TxnLog
hdr
- the transaction headertxn
- the transaction itselfdigest
- transaction digest
returns true iff something appended, otw falseIOException
public static File[] getLogFiles(File[] logDirList, long snapshotZxid)
logDirList
- array of filessnapshotZxid
- return files at, or before this zxidpublic long getLastLoggedZxid()
getLastLoggedZxid
in interface TxnLog
public void commit() throws IOException
commit
in interface TxnLog
IOException
public long getTxnLogSyncElapsedTime()
getTxnLogSyncElapsedTime
in interface TxnLog
public TxnLog.TxnIterator read(long zxid) throws IOException
read
in interface TxnLog
zxid
- the zxid to start reading transactions fromIOException
public TxnLog.TxnIterator read(long zxid, boolean fastForward) throws IOException
zxid
- the zxid to start reading transactions fromfastForward
- true if the iterator should be fast forwarded to point
to the txn of a given zxid, else the iterator will point to the
starting txn of a txnlog that may contain txn of a given zxidIOException
public boolean truncate(long zxid) throws IOException
truncate
in interface TxnLog
zxid
- the zxid to truncate the logs toIOException
public long getDbId() throws IOException
getDbId
in interface TxnLog
IOException
public boolean isForceSync()
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