org.apache.jackrabbit.oak.plugins.document

Class VersionGCOptions

java.lang.Object

org.apache.jackrabbit.oak.plugins.document.VersionGCOptions

public class VersionGCOptions
extends java.lang.Object

Field Summary

Fields

Modifier and Type	Field and Description
long	collectLimit
double	delayFactor
long	maxDurationMs
int	maxIterations
int	overflowToDiskThreshold
long	precisionMs

Constructor Summary

Constructors

Constructor and Description
VersionGCOptions()

Method Summary

Modifier and Type	Method and Description
VersionGCOptions	withCollectLimit(long limit) Sets the absolute limit on number of resource ids collected in one run.
VersionGCOptions	withDelayFactor(double f) Set a delay factor between batched database modifications.
VersionGCOptions	withMaxDuration(java.util.concurrent.TimeUnit unit, long t) Set the maximum duration in elapsed time that the garbage collection shall take.
VersionGCOptions	withMaxIterations(int max) Set the maximum number of iterations that shall be attempted in a single run.
VersionGCOptions	withOverflowToDiskThreshold(int overflowToDiskThreshold) Set the limit of number of resource id+_modified strings (not length) held in memory during a collection run.
VersionGCOptions	withPrecisionMs(java.util.concurrent.TimeUnit unit, long t) Set the minimum duration that is used for time based searches.

Methods inherited from class java.lang.Object

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

Field Detail

overflowToDiskThreshold

public final int overflowToDiskThreshold

collectLimit

public final long collectLimit

precisionMs

public final long precisionMs

maxIterations

public final int maxIterations

maxDurationMs

public final long maxDurationMs

delayFactor

public final double delayFactor

Constructor Detail

VersionGCOptions

public VersionGCOptions()

Method Detail

withOverflowToDiskThreshold

public VersionGCOptions withOverflowToDiskThreshold(int overflowToDiskThreshold)

Set the limit of number of resource id+_modified strings (not length) held in memory during a collection run. Any more will be stored and sorted in a temporary file.

Parameters:

overflowToDiskThreshold - limit after which to use file based storage for candidate ids

withCollectLimit

public VersionGCOptions withCollectLimit(long limit)

Sets the absolute limit on number of resource ids collected in one run. This does not count nodes which can be deleted immediately. When this limit is exceeded, the run either fails or is attempted with different parameters, depending on other settings. Note that if the inspected time interval is equal or less than precisionMs, the collection limit will be ignored.

Parameters:

limit - the absolute limit of resources collected in one run

withPrecisionMs

public VersionGCOptions withPrecisionMs(java.util.concurrent.TimeUnit unit,
                                        long t)

Set the minimum duration that is used for time based searches. This should at minimum be the precision available on modification dates of documents, but can be set larger to avoid querying the database too often. Note however that collectLimit will not take effect for runs that query equal or shorter than precision duration.

Parameters:

unit - time unit used for duration

t - the number of units in the duration

withMaxDuration

public VersionGCOptions withMaxDuration(java.util.concurrent.TimeUnit unit,
                                        long t)

Set the maximum duration in elapsed time that the garbage collection shall take. Setting this to 0 means that there is no limit imposed. A positive duration will impose a soft limit, e.g. the collection might take longer, but no next iteration will be attempted afterwards. See withMaxIterations(int) on how to control the behaviour.

Parameters:

unit - time unit used for duration

t - the number of units in the duration

withMaxIterations

public VersionGCOptions withMaxIterations(int max)

Set the maximum number of iterations that shall be attempted in a single run. A value of 0 means that there is no limit. Since the garbage collector uses iterations to find suitable time intervals and set sizes for cleanups, limiting the iterations is only recommended for setups where the collector is called often.

Parameters:

max - the maximum number of iterations allowed

withDelayFactor

public VersionGCOptions withDelayFactor(double f)

Set a delay factor between batched database modifications. This rate limits the writes to the database by a garbage collector. 0, e.g. no delay, is the default. This is recommended when garbage collection is done during a maintenance time when other system load is low.

For factory > 0, the actual delay is the duration of the last batch modification times the factor. Example: 0.25 would result in a 25% delay, e.g. a batch modification running 10 seconds would be followed by a sleep of 2.5 seconds.

Parameters:

f - the factor used to calculate batch modification delays