org.rocksdb.PlainTableConfig Maven / Gradle / Ivy
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
package org.rocksdb;
/**
* The config for plain table sst format.
*
* PlainTable is a RocksDB's SST file format optimized for low query
* latency on pure-memory or really low-latency media.
*
* It also support prefix hash feature.
*/
public class PlainTableConfig extends TableFormatConfig {
public static final int VARIABLE_LENGTH = 0;
public static final int DEFAULT_BLOOM_BITS_PER_KEY = 10;
public static final double DEFAULT_HASH_TABLE_RATIO = 0.75;
public static final int DEFAULT_INDEX_SPARSENESS = 16;
public static final int DEFAULT_HUGE_TLB_SIZE = 0;
public static final EncodingType DEFAULT_ENCODING_TYPE =
EncodingType.kPlain;
public static final boolean DEFAULT_FULL_SCAN_MODE = false;
public static final boolean DEFAULT_STORE_INDEX_IN_FILE
= false;
public PlainTableConfig() {
keySize_ = VARIABLE_LENGTH;
bloomBitsPerKey_ = DEFAULT_BLOOM_BITS_PER_KEY;
hashTableRatio_ = DEFAULT_HASH_TABLE_RATIO;
indexSparseness_ = DEFAULT_INDEX_SPARSENESS;
hugePageTlbSize_ = DEFAULT_HUGE_TLB_SIZE;
encodingType_ = DEFAULT_ENCODING_TYPE;
fullScanMode_ = DEFAULT_FULL_SCAN_MODE;
storeIndexInFile_ = DEFAULT_STORE_INDEX_IN_FILE;
}
/**
* Set the length of the user key. If it is set to be
* VARIABLE_LENGTH, then it indicates the user keys are
* of variable length.
*
* Otherwise,all the keys need to have the same length
* in byte.
*
* DEFAULT: VARIABLE_LENGTH
*
* @param keySize the length of the user key.
* @return the reference to the current config.
*/
public PlainTableConfig setKeySize(final int keySize) {
keySize_ = keySize;
return this;
}
/**
* @return the specified size of the user key. If VARIABLE_LENGTH,
* then it indicates variable-length key.
*/
public int keySize() {
return keySize_;
}
/**
* Set the number of bits per key used by the internal bloom filter
* in the plain table sst format.
*
* @param bitsPerKey the number of bits per key for bloom filer.
* @return the reference to the current config.
*/
public PlainTableConfig setBloomBitsPerKey(final int bitsPerKey) {
bloomBitsPerKey_ = bitsPerKey;
return this;
}
/**
* @return the number of bits per key used for the bloom filter.
*/
public int bloomBitsPerKey() {
return bloomBitsPerKey_;
}
/**
* hashTableRatio is the desired utilization of the hash table used
* for prefix hashing. The ideal ratio would be the number of
* prefixes / the number of hash buckets. If this value is set to
* zero, then hash table will not be used.
*
* @param ratio the hash table ratio.
* @return the reference to the current config.
*/
public PlainTableConfig setHashTableRatio(final double ratio) {
hashTableRatio_ = ratio;
return this;
}
/**
* @return the hash table ratio.
*/
public double hashTableRatio() {
return hashTableRatio_;
}
/**
* Index sparseness determines the index interval for keys inside the
* same prefix. This number is equal to the maximum number of linear
* search required after hash and binary search. If it's set to 0,
* then each key will be indexed.
*
* @param sparseness the index sparseness.
* @return the reference to the current config.
*/
public PlainTableConfig setIndexSparseness(final int sparseness) {
indexSparseness_ = sparseness;
return this;
}
/**
* @return the index sparseness.
*/
public long indexSparseness() {
return indexSparseness_;
}
/**
* huge_page_tlb_size: if ≤0, allocate hash indexes and blooms
* from malloc otherwise from huge page TLB.
*
* The user needs to reserve huge pages for it to be allocated,
* like: {@code sysctl -w vm.nr_hugepages=20}
*
* See linux doc Documentation/vm/hugetlbpage.txt
*
* @param hugePageTlbSize huge page tlb size
* @return the reference to the current config.
*/
public PlainTableConfig setHugePageTlbSize(final int hugePageTlbSize) {
this.hugePageTlbSize_ = hugePageTlbSize;
return this;
}
/**
* Returns the value for huge page tlb size
*
* @return hugePageTlbSize
*/
public int hugePageTlbSize() {
return hugePageTlbSize_;
}
/**
* Sets the encoding type.
*
* This setting determines how to encode
* the keys. See enum {@link EncodingType} for
* the choices.
*
* The value will determine how to encode keys
* when writing to a new SST file. This value will be stored
* inside the SST file which will be used when reading from
* the file, which makes it possible for users to choose
* different encoding type when reopening a DB. Files with
* different encoding types can co-exist in the same DB and
* can be read.
*
* @param encodingType {@link org.rocksdb.EncodingType} value.
* @return the reference to the current config.
*/
public PlainTableConfig setEncodingType(final EncodingType encodingType) {
this.encodingType_ = encodingType;
return this;
}
/**
* Returns the active EncodingType
*
* @return currently set encoding type
*/
public EncodingType encodingType() {
return encodingType_;
}
/**
* Set full scan mode, if true the whole file will be read
* one record by one without using the index.
*
* @param fullScanMode boolean value indicating if full
* scan mode shall be enabled.
* @return the reference to the current config.
*/
public PlainTableConfig setFullScanMode(final boolean fullScanMode) {
this.fullScanMode_ = fullScanMode;
return this;
}
/**
* Return if full scan mode is active
* @return boolean value indicating if the full scan mode is
* enabled.
*/
public boolean fullScanMode() {
return fullScanMode_;
}
/**
* If set to true: compute plain table index and bloom
* filter during file building and store it in file.
* When reading file, index will be mmaped instead
* of doing recomputation.
*
* @param storeIndexInFile value indicating if index shall
* be stored in a file
* @return the reference to the current config.
*/
public PlainTableConfig setStoreIndexInFile(final boolean storeIndexInFile) {
this.storeIndexInFile_ = storeIndexInFile;
return this;
}
/**
* Return a boolean value indicating if index shall be stored
* in a file.
*
* @return currently set value for store index in file.
*/
public boolean storeIndexInFile() {
return storeIndexInFile_;
}
@Override protected long newTableFactoryHandle() {
return newTableFactoryHandle(keySize_, bloomBitsPerKey_,
hashTableRatio_, indexSparseness_, hugePageTlbSize_,
encodingType_.getValue(), fullScanMode_,
storeIndexInFile_);
}
private static native long newTableFactoryHandle(int keySize, int bloomBitsPerKey,
double hashTableRatio, int indexSparseness, int hugePageTlbSize, byte encodingType,
boolean fullScanMode, boolean storeIndexInFile);
private int keySize_;
private int bloomBitsPerKey_;
private double hashTableRatio_;
private int indexSparseness_;
private int hugePageTlbSize_;
private EncodingType encodingType_;
private boolean fullScanMode_;
private boolean storeIndexInFile_;
}