com.sleepycat.je
Class PreloadConfig

java.lang.Object
  com.sleepycat.je.PreloadConfig

All Implemented Interfaces:

Cloneable

public class PreloadConfig
extends Object
implements Cloneable

Specifies the attributes of an application invoked preload operation.

Nested Class Summary

static class

PreloadConfig.Phases Preload progress listeners report this phase value, along with a count of the number if times that the preload has fetched from disk.

Constructor Summary

PreloadConfig()
Default configuration used if null is passed to Database.preload.

Method Summary

PreloadConfig	clone() Returns a copy of this configuration object.
long	getInternalMemoryLimit() Returns the maximum amount of non JE Cache Memory that preload can use at one time.
boolean	getLoadLNs() Return the configuration of the preload load LNs option.
long	getLSNBatchSize() Preload is implemented to optimize I/O cost by fetching the records of a Database by disk order, so that disk access is are sequential rather than random.
long	getMaxBytes() Return the number of bytes in the cache to stop the preload at.
long	getMaxMillisecs() Return the number of millisecs to stop the preload after.
ProgressListener<PreloadConfig.Phases>	getProgressListener() Return the ProgressListener for this PreloadConfig.
PreloadConfig	setInternalMemoryLimit(long internalMemoryLimit) Set the maximum amount of non JE Cache Memory that preload can use at one time.
PreloadConfig	setLoadLNs(boolean loadLNs) Configure the preload load LNs option.
PreloadConfig	setLSNBatchSize(long lsnBatchSize) Set the maximum number of LSNs to gather and sort at any one time.
PreloadConfig	setMaxBytes(long maxBytes) Configure the maximum number of bytes to preload.
PreloadConfig	setMaxMillisecs(long maxMillisecs) Configure the maximum number of milliseconds to execute preload.
PreloadConfig	setProgressListener(ProgressListener<PreloadConfig.Phases> progressListener) Configure the preload operation to make periodic calls to a ProgressListener to provide feedback on preload progress.
String	toString() Returns the values for each configuration attribute.

Methods inherited from class java.lang.Object

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

Constructor Detail

PreloadConfig

public PreloadConfig()

Default configuration used if null is passed to Database.preload.

Method Detail

setMaxBytes

public PreloadConfig setMaxBytes(long maxBytes)

Configure the maximum number of bytes to preload.

The default is 0 for this class.

Parameters:

maxBytes - If the maxBytes parameter is non-zero, a preload will stop when the cache contains this number of bytes.

Returns:

this

getMaxBytes

public long getMaxBytes()

Return the number of bytes in the cache to stop the preload at.

This method may be called at any time during the life of the application.

Returns:

The number of bytes in the cache to stop the preload at.

setMaxMillisecs

public PreloadConfig setMaxMillisecs(long maxMillisecs)

Configure the maximum number of milliseconds to execute preload.

The default is 0 for this class.

Parameters:

maxMillisecs - If the maxMillisecs parameter is non-zero, a preload will stop when this amount of time has passed.

Returns:

this

getMaxMillisecs

public long getMaxMillisecs()

Return the number of millisecs to stop the preload after.

This method may be called at any time during the life of the application.

Returns:

The number of millisecs to stop the preload after.

setLoadLNs

public PreloadConfig setLoadLNs(boolean loadLNs)

Configure the preload load LNs option.

The default is false for this class.

Parameters:

loadLNs - If set to true, the preload will load Leaf Nodes (LNs) containing the data values.

Returns:

this

getLoadLNs

public boolean getLoadLNs()

Return the configuration of the preload load LNs option.

Returns:

The configuration of the preload load LNs option.

setProgressListener

public PreloadConfig setProgressListener(ProgressListener<PreloadConfig.Phases> progressListener)

Configure the preload operation to make periodic calls to a ProgressListener to provide feedback on preload progress. The ProgressListener.progress() method is called each time the preload mush fetch a btree node or data record from disk.

When using progress listeners, review the information at ProgressListener.progress(T, long, long) to avoid any unintended disruption to replication stream syncup.

Parameters:

progressListener - The ProgressListener to callback during preload.

getProgressListener

public ProgressListener<PreloadConfig.Phases> getProgressListener()

Return the ProgressListener for this PreloadConfig.

Returns:

the ProgressListener for this PreloadConfig.

setLSNBatchSize

public PreloadConfig setLSNBatchSize(long lsnBatchSize)

Set the maximum number of LSNs to gather and sort at any one time. The default is an unlimited number of LSNs. Setting this lower causes the preload to use less memory, but it sorts and processes LSNs more frequently thereby causing slower performance. Setting this higher will in general improve performance at the expense of memory. Each LSN uses 16 bytes of memory.

Parameters:

lsnBatchSize - the maximum number of LSNs to accumulate and sort per batch.

Returns:

this

getLSNBatchSize

public long getLSNBatchSize()

Preload is implemented to optimize I/O cost by fetching the records of a Database by disk order, so that disk access is are sequential rather than random. LSNs (log sequence numbers) are the disk addresses of database records. Setting this value causes the preload to process batches of LSNs rather than all in-memory LSNs at one time, which bounds the memory usage of the preload processing, at the expense of preload performance.

Returns:

the maximum number of LSNs to be sorted that this preload is configured for.

setInternalMemoryLimit

public PreloadConfig setInternalMemoryLimit(long internalMemoryLimit)

Set the maximum amount of non JE Cache Memory that preload can use at one time. The default is an unlimited amount of memory. Setting this lower causes the preload to use less memory, but generally results in slower performance. Setting this higher will often improve performance at the expense of higher memory utilization.

Parameters:

internalMemoryLimit - the maximum number of non JE Cache bytes to use.

Returns:

this

getInternalMemoryLimit

public long getInternalMemoryLimit()

Returns the maximum amount of non JE Cache Memory that preload can use at one time.

Returns:

the maximum amount of non JE Cache Memory that preload can use at one time.

clone

public PreloadConfig clone()

Returns a copy of this configuration object.

Overrides:

clone in class Object

toString

public String toString()

Returns the values for each configuration attribute.

Overrides:

toString in class Object

Returns:

the values for each configuration attribute.