com.sleepycat.je.evictor
Class Evictor

java.lang.Object
  com.sleepycat.je.utilint.DaemonThread
      com.sleepycat.je.evictor.Evictor

All Implemented Interfaces:

DaemonRunner, java.lang.Runnable

Direct Known Subclasses:

PrivateEvictor, SharedEvictor

public abstract class Evictor
extends DaemonThread

The Evictor looks through the INList for IN's and BIN's that are worthy of eviction. Once the nodes are selected, it removes all references to them so that they can be GC'd by the JVM.

Nested Class Summary

(package private) static class

Evictor.EvictProfile

Field Summary

(package private) Evictor.EvictProfile	evictProfile
static java.lang.String	SOURCE_CRITICAL
static java.lang.String	SOURCE_DAEMON
static java.lang.String	SOURCE_MANUAL

Fields inherited from class com.sleepycat.je.utilint.DaemonThread

name, nWakeupRequests, stifleExceptionChatter

Constructor Summary

Evictor(EnvironmentImpl envImpl, java.lang.String name)

Method Summary

abstract void	addEnvironment(EnvironmentImpl envImpl) Only supported by SharedEvictor.
void	alert() Wakeup the evictor only if it's not already active.
abstract boolean	checkEnvs(java.util.Set<EnvironmentImpl> envs) Only supported by SharedEvictor.
abstract void	clearEnv() Standard daemon method to set envImpl to null.
void	doCriticalEviction(boolean backgroundIO) Do a check on whether synchronous eviction is needed.
void	doEvict(java.lang.String source) May be called by the evictor thread on wakeup or programatically.
(package private) long	evictBatch(java.lang.String source, boolean backgroundIO, long requiredEvictBytes) Each iteration will attempt to evict requiredEvictBytes, but will give up after a complete pass over the INList.
(package private) abstract java.util.logging.Logger	getLogger()
(package private) abstract int	getMaxINsPerBatch() Returns the approximate number of total INs in the INList(s).
(package private) abstract IN	getNextIN() Returns the next IN in the INList(s), wrapping if necessary.
(package private) abstract java.util.Iterator<IN>	getScanIterator()
void	loadStats(StatsConfig config, EnvironmentStats stat) Load stats.
protected long	nDeadlockRetries() Return the number of retries when a deadlock exception occurs.
int	normalizeLevel(IN in, int evictType) Normalize the tree level of the given IN.
abstract void	noteINListChange(int nINs) Called whenever INs are added to, or removed from, the INList.
void	onWakeup() Called whenever the daemon thread wakes up from a sleep.
abstract void	removeEnvironment(EnvironmentImpl envImpl) Only supported by SharedEvictor.
void	setRunnableHook(TestHook hook)
(package private) abstract void	setScanIterator(java.util.Iterator<IN> iter)
(package private) abstract long	startBatch() Perform class-specific batch processing: Initialize iterator, perform UtilizationTracker eviction, etc.

Methods inherited from class com.sleepycat.je.utilint.DaemonThread

checkErrorListener, getExceptionListener, getNWakeupRequests, getThread, isPaused, isRunning, isShutdownRequested, requestShutdown, run, runOrPause, setExceptionListener, shutdown, toString, wakeup

Methods inherited from class java.lang.Object

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

Field Detail

SOURCE_DAEMON

public static final java.lang.String SOURCE_DAEMON

See Also:

Constant Field Values

SOURCE_MANUAL

public static final java.lang.String SOURCE_MANUAL

See Also:

Constant Field Values

SOURCE_CRITICAL

public static final java.lang.String SOURCE_CRITICAL

See Also:

Constant Field Values

evictProfile

Evictor.EvictProfile evictProfile

Constructor Detail

Evictor

Evictor(EnvironmentImpl envImpl,
        java.lang.String name)
  throws DatabaseException

Throws:

DatabaseException

Method Detail

loadStats

public void loadStats(StatsConfig config,
                      EnvironmentStats stat)
               throws DatabaseException

Load stats.

Throws:

DatabaseException

nDeadlockRetries

protected long nDeadlockRetries()
                         throws DatabaseException

Return the number of retries when a deadlock exception occurs.

Overrides:

nDeadlockRetries in class DaemonThread

Throws:

DatabaseException

alert

public void alert()

Wakeup the evictor only if it's not already active.

onWakeup

public void onWakeup()
              throws DatabaseException

Called whenever the daemon thread wakes up from a sleep.

Specified by:

onWakeup in class DaemonThread

Throws:

DatabaseException

doEvict

public void doEvict(java.lang.String source)
             throws DatabaseException

May be called by the evictor thread on wakeup or programatically.

Throws:

DatabaseException

doCriticalEviction

public void doCriticalEviction(boolean backgroundIO)
                        throws DatabaseException

Do a check on whether synchronous eviction is needed.

Throws:

DatabaseException

evictBatch

long evictBatch(java.lang.String source,
                boolean backgroundIO,
                long requiredEvictBytes)
          throws DatabaseException

Each iteration will attempt to evict requiredEvictBytes, but will give up after a complete pass over the INList.

Returns:

the number of bytes evicted, or zero if no progress was made.

Throws:

DatabaseException

normalizeLevel

public int normalizeLevel(IN in,
                          int evictType)

Normalize the tree level of the given IN. Is public for unit testing. A BIN containing evictable LNs is given level 0, so it will be stripped first. For non-duplicate and DBMAP trees, the high order bits are cleared to make their levels correspond; that way, all bottom level nodes (BINs and DBINs) are given the same eviction priority. Note that BINs in a duplicate tree are assigned the same level as BINs in a non-duplicate tree. This isn't always optimimal, but is the best we can do considering that BINs in duplicate trees may contain a mix of LNs and DINs. BINs in the mapping tree are also assigned the same level as user DB BINs. When doing by-level eviction (lruOnly=false), this seems counter-intuitive since we should evict user DB nodes before mapping DB nodes. But that does occur because mapping DB INs referencing an open DB are unevictable. The level is only used for selecting among evictable nodes. If we did NOT normalize the level for the mapping DB, then INs for closed evictable DBs would not be evicted until after all nodes in all user DBs were evicted. If there were large numbers of closed DBs, this would have a negative performance impact.

setRunnableHook

public void setRunnableHook(TestHook hook)

clearEnv

public abstract void clearEnv()

Standard daemon method to set envImpl to null.

noteINListChange

public abstract void noteINListChange(int nINs)

Called whenever INs are added to, or removed from, the INList.

addEnvironment

public abstract void addEnvironment(EnvironmentImpl envImpl)

Only supported by SharedEvictor.

removeEnvironment

public abstract void removeEnvironment(EnvironmentImpl envImpl)

Only supported by SharedEvictor.

checkEnvs

public abstract boolean checkEnvs(java.util.Set<EnvironmentImpl> envs)

Only supported by SharedEvictor.

getLogger

abstract java.util.logging.Logger getLogger()

startBatch

abstract long startBatch()
                  throws DatabaseException

Perform class-specific batch processing: Initialize iterator, perform UtilizationTracker eviction, etc. No latches may be held when this method is called. startBatch must be called before getMaxINsPerBatch.

Throws:

DatabaseException

getMaxINsPerBatch

abstract int getMaxINsPerBatch()

Returns the approximate number of total INs in the INList(s). One eviction batch will scan at most this number of INs. If zero is returned, selectIN will not be called. startBatch must be called before getMaxINsPerBatch.

getNextIN

abstract IN getNextIN()

Returns the next IN in the INList(s), wrapping if necessary.

getScanIterator

abstract java.util.Iterator<IN> getScanIterator()

setScanIterator

abstract void setScanIterator(java.util.Iterator<IN> iter)