org.apache.jackrabbit.oak.plugins.document.VersionGCOptions Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.jackrabbit.oak.plugins.document;
import java.util.concurrent.TimeUnit;
public class VersionGCOptions {
public final int overflowToDiskThreshold;
public final long collectLimit;
public final long precisionMs;
public final int maxIterations;
public final long maxDurationMs;
public final double delayFactor;
public VersionGCOptions() {
this(100000, 100000, TimeUnit.MINUTES.toMillis(1),
0, TimeUnit.HOURS.toMillis(0), 0);
}
private VersionGCOptions(int overflow, long collectLimit, long precisionMs,
int maxIterations, long maxDurationMs, double delayFactor) {
this.overflowToDiskThreshold = overflow;
this.collectLimit = collectLimit;
this.precisionMs = precisionMs;
this.maxIterations = maxIterations;
this.maxDurationMs = maxDurationMs;
this.delayFactor = delayFactor;
}
/**
* 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.
* @param overflowToDiskThreshold limit after which to use file based storage for candidate ids
*/
public VersionGCOptions withOverflowToDiskThreshold(int overflowToDiskThreshold) {
return new VersionGCOptions(overflowToDiskThreshold, this.collectLimit,
this.precisionMs, this.maxIterations, this.maxDurationMs, this.delayFactor);
}
/**
* 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 {@link #precisionMs}, the collection limit will be ignored.
*
* @param limit the absolute limit of resources collected in one run
*/
public VersionGCOptions withCollectLimit(long limit) {
return new VersionGCOptions(this.overflowToDiskThreshold, limit,
this.precisionMs, this.maxIterations, this.maxDurationMs, this.delayFactor);
}
/**
* 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 {@link #collectLimit} will not take effect for runs
* that query equal or shorter than precision duration.
*
* @param unit time unit used for duration
* @param t the number of units in the duration
*/
public VersionGCOptions withPrecisionMs(TimeUnit unit, long t) {
return new VersionGCOptions(this.overflowToDiskThreshold, this.collectLimit,
unit.toMillis(t), this.maxIterations, this.maxDurationMs, this.delayFactor);
}
/**
* 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
* {@link #withMaxIterations(int)} on how to control the behaviour.
*
* @param unit time unit used for duration
* @param t the number of units in the duration
*/
public VersionGCOptions withMaxDuration(TimeUnit unit, long t) {
return new VersionGCOptions(this.overflowToDiskThreshold, this.collectLimit,
this.precisionMs, this.maxIterations, unit.toMillis(t), this.delayFactor);
}
/**
* 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.
*
* @param max the maximum number of iterations allowed
*/
public VersionGCOptions withMaxIterations(int max) {
return new VersionGCOptions(this.overflowToDiskThreshold, this.collectLimit,
this.precisionMs, this.maxIterations, max, this.delayFactor);
}
/**
* 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.
*
* @param f the factor used to calculate batch modification delays
*/
public VersionGCOptions withDelayFactor(double f) {
return new VersionGCOptions(this.overflowToDiskThreshold, this.collectLimit,
this.precisionMs, this.maxIterations, this.maxDurationMs, f);
}
}