com.sleepycat.je.utilint

Class DbLsn

java.lang.Object

com.sleepycat.je.utilint.DbLsn

public class DbLsn
extends Object

DbLsn is a class that operates on Log Sequence Numbers (LSNs). An LSN is a long comprised of a file number (32b) and offset within that file (32b) which references a unique record in the database environment log. While LSNs are represented as long's, we operate on them using an abstraction and return longs from these methods so that we don't have to worry about the lack of unsigned quantities.

Field Summary

Fields

Modifier and Type	Field and Description
static long	MAX_FILE_NUM
static long	MAX_FILE_OFFSET
static long	NULL_LSN

Method Summary

Modifier and Type	Method and Description
static int	compareTo(long lsn1, long lsn2)
static long	convertIntFileOffsetToLong(int storedLsn)
static String	dumpString(long lsn, int nSpaces)
static long	getFileNumber(long lsn) Return the file number for this DbLsn.
static long	getFileOffset(long lsn) Return the file offset for this DbLsn.
static int	getFileOffsetAsInt(long lsn)
static long	getNoCleaningDistance(long thisLsn, long otherLsn, long logFileSize) Return the logsize in bytes between these two LSNs.
static String	getNoFormatString(long lsn)
static long	getTrueDistance(long thisLsn, long otherLsn, FileManager fileManager) Returns the number of bytes between two LSNs, counting the true size of each intermediate file.
static long	getWithCleaningDistance(long thisLsn, long otherLsn, long logFileSize, FileManager fileManager) Return the logsize in bytes between these two LSNs.
static boolean	isTransient(long lsn) A transient LSN is defined as one with a file number of MAX_FILE_NUM.
static boolean	isTransientOrNull(long lsn)
static long	longToLsn(Long lsn)
static long	makeLsn(long fileNumber, int fileOffset) This flavor of makeLsn is used when the file offset has been stored in 32 bits, as is done in the VLSNBucket.
static long	makeLsn(long fileNumber, long fileOffset)
static long	makeTransientLsn(long fileOffset) For transient LSNs we use the MAX_FILE_NUM and the ascending sequence of offsets.
static String	toString(long lsn)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAX_FILE_OFFSET

public static final long MAX_FILE_OFFSET

See Also:

Constant Field Values

MAX_FILE_NUM

public static final long MAX_FILE_NUM

See Also:

Constant Field Values

NULL_LSN

public static final long NULL_LSN

See Also:

Constant Field Values

Method Detail

makeLsn

public static long makeLsn(long fileNumber,
                           long fileOffset)

makeLsn

public static long makeLsn(long fileNumber,
                           int fileOffset)

This flavor of makeLsn is used when the file offset has been stored in 32 bits, as is done in the VLSNBucket.

makeTransientLsn

public static long makeTransientLsn(long fileOffset)

For transient LSNs we use the MAX_FILE_NUM and the ascending sequence of offsets.

isTransient

public static boolean isTransient(long lsn)

A transient LSN is defined as one with a file number of MAX_FILE_NUM.

isTransientOrNull

public static boolean isTransientOrNull(long lsn)

longToLsn

public static long longToLsn(Long lsn)

getFileNumber

public static long getFileNumber(long lsn)

Return the file number for this DbLsn.

Returns:

the number for this DbLsn.

getFileOffset

public static long getFileOffset(long lsn)

Return the file offset for this DbLsn.

Returns:

the offset for this DbLsn.

getFileOffsetAsInt

public static int getFileOffsetAsInt(long lsn)

convertIntFileOffsetToLong

public static long convertIntFileOffsetToLong(int storedLsn)

compareTo

public static int compareTo(long lsn1,
                            long lsn2)

toString

public static String toString(long lsn)

getNoFormatString

public static String getNoFormatString(long lsn)

dumpString

public static String dumpString(long lsn,
                                int nSpaces)

getNoCleaningDistance

public static long getNoCleaningDistance(long thisLsn,
                                         long otherLsn,
                                         long logFileSize)

Return the logsize in bytes between these two LSNs. This is an approximation; the logs might actually be a little more or less in size. This assumes that no log files have been cleaned.

getWithCleaningDistance

public static long getWithCleaningDistance(long thisLsn,
                                           long otherLsn,
                                           long logFileSize,
                                           FileManager fileManager)

Return the logsize in bytes between these two LSNs. This is an approximation; the logs might actually be a little more or less in size. This assumes that log files might have been cleaned.

getTrueDistance

public static long getTrueDistance(long thisLsn,
                                   long otherLsn,
                                   FileManager fileManager)

Returns the number of bytes between two LSNs, counting the true size of each intermediate file. Assumes that all files in the LSN range are currently protected from cleaner deletion, e.g., during recovery. Uses File.length and does not perturb the FileManager's file handle cache.