com.sleepycat.je.cleaner

Class ExpirationTracker

java.lang.Object

com.sleepycat.je.cleaner.ExpirationTracker

public class ExpirationTracker
extends Object

Tracks the expired bytes in each time window, i.e., a histogram. A separate ExpirationTracker instance is used for each tracked data file.

A copy-on-write approach is used to store a file number-to-counter mapping, and AtomicIntegers are used for the counters. This avoids blocking when tracking information for the current end-of-log file. That way, the end-of-log tracker can be used by multiple threads without holding a global mutex. This tracker is maintained by the LogManager and a new tracker is created for each file, and then flushed to disk when starting a new file as a FileExpirationLN.

An ExpirationTracker instance is used to track expired data when performing the first pass of two pass cleaning, although in that case it is only used by one thread, so the optimizations are irrelevant.

The serialize()} method is called to represent the histogram in a single byte array. This array is the record "data" in a FileExpirationLN. It is also stored in memory, in the UtilizationProfile, and used during cleaning to calculate the number of expired bytes per file.

Constructor Summary

Constructors

Constructor and Description
ExpirationTracker(long fileNum)

Method Summary

Modifier and Type	Method and Description
int	getExpiredBytes(long time) Computes the current expired bytes for the given time.
long	getFileNum()
void	incrementPendingTrackCalls() Increment the number of calls to track(int, boolean, int) that must be made before the tracked data can be flushed to its database.
String	toString()
static String	toString(byte[] serializedForm)
void	track(LogEntry entry, int size) Tracks expiration of a BIN or LN.

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpirationTracker

public ExpirationTracker(long fileNum)

Method Detail

getFileNum

public long getFileNum()

track

public void track(LogEntry entry,
                  int size)

Tracks expiration of a BIN or LN.

Parameters:

entry - is the LogEntry that was just logged. INs and LNs will be processed here, and must be protected by their parent latch.

size - byte size of logged entry.

incrementPendingTrackCalls

public void incrementPendingTrackCalls()

Increment the number of calls to track(int, boolean, int) that must be made before the tracked data can be flushed to its database.

getExpiredBytes

public int getExpiredBytes(long time)

Computes the current expired bytes for the given time.

toString

public String toString()

Overrides:

toString in class Object

toString

public static String toString(byte[] serializedForm)