org.rocksdb.HashSkipListMemTableConfig Maven / Gradle / Ivy
// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
package org.rocksdb;
/**
* The config for hash skip-list mem-table representation.
* Such mem-table representation contains a fix-sized array of
* buckets, where each bucket points to a skiplist (or null if the
* bucket is empty).
*
* Note that since this mem-table representation relies on the
* key prefix, it is required to invoke one of the usePrefixExtractor
* functions to specify how to extract key prefix given a key.
* If proper prefix-extractor is not set, then RocksDB will
* use the default memtable representation (SkipList) instead
* and post a warning in the LOG.
*/
public class HashSkipListMemTableConfig extends MemTableConfig {
public static final int DEFAULT_BUCKET_COUNT = 1000000;
public static final int DEFAULT_BRANCHING_FACTOR = 4;
public static final int DEFAULT_HEIGHT = 4;
/**
* HashSkipListMemTableConfig constructor
*/
public HashSkipListMemTableConfig() {
bucketCount_ = DEFAULT_BUCKET_COUNT;
branchingFactor_ = DEFAULT_BRANCHING_FACTOR;
height_ = DEFAULT_HEIGHT;
}
/**
* Set the number of hash buckets used in the hash skiplist memtable.
* Default = 1000000.
*
* @param count the number of hash buckets used in the hash
* skiplist memtable.
* @return the reference to the current HashSkipListMemTableConfig.
*/
public HashSkipListMemTableConfig setBucketCount(
final long count) {
bucketCount_ = count;
return this;
}
/**
* @return the number of hash buckets
*/
public long bucketCount() {
return bucketCount_;
}
/**
* Set the height of the skip list. Default = 4.
*
* @param height height to set.
*
* @return the reference to the current HashSkipListMemTableConfig.
*/
public HashSkipListMemTableConfig setHeight(final int height) {
height_ = height;
return this;
}
/**
* @return the height of the skip list.
*/
public int height() {
return height_;
}
/**
* Set the branching factor used in the hash skip-list memtable.
* This factor controls the probabilistic size ratio between adjacent
* links in the skip list.
*
* @param bf the probabilistic size ratio between adjacent link
* lists in the skip list.
* @return the reference to the current HashSkipListMemTableConfig.
*/
public HashSkipListMemTableConfig setBranchingFactor(
final int bf) {
branchingFactor_ = bf;
return this;
}
/**
* @return branching factor, the probabilistic size ratio between
* adjacent links in the skip list.
*/
public int branchingFactor() {
return branchingFactor_;
}
@Override protected long newMemTableFactoryHandle() {
return newMemTableFactoryHandle(
bucketCount_, height_, branchingFactor_);
}
private native long newMemTableFactoryHandle(
long bucketCount, int height, int branchingFactor)
throws IllegalArgumentException;
private long bucketCount_;
private int branchingFactor_;
private int height_;
}