Package org.rocksdb

Class CompactionOptionsUniversal

  • All Implemented Interfaces:
    java.lang.AutoCloseable
    public class CompactionOptionsUniversal
extends RocksObject
    Options for Universal Compaction

    • Constructor Detail

      • CompactionOptionsUniversal

        public CompactionOptionsUniversal()

    • Method Detail

      • setSizeRatio

        public CompactionOptionsUniversal setSizeRatio​(int sizeRatio)
        Percentage flexibility while comparing file size. If the candidate file(s) size is 1% smaller than the next file's size, then include next file into this candidate set. Default: 1
        Parameters:
        sizeRatio - The size ratio to use
        Returns:
        the reference to the current options.

      • sizeRatio

        public int sizeRatio()
        Percentage flexibility while comparing file size. If the candidate file(s) size is 1% smaller than the next file's size, then include next file into this candidate set. Default: 1
        Returns:
        The size ratio in use

      • setMinMergeWidth

        public CompactionOptionsUniversal setMinMergeWidth​(int minMergeWidth)
        The minimum number of files in a single compaction run. Default: 2
        Parameters:
        minMergeWidth - minimum number of files in a single compaction run
        Returns:
        the reference to the current options.

      • minMergeWidth

        public int minMergeWidth()
        The minimum number of files in a single compaction run. Default: 2
        Returns:
        minimum number of files in a single compaction run

      • setMaxMergeWidth

        public CompactionOptionsUniversal setMaxMergeWidth​(int maxMergeWidth)
        The maximum number of files in a single compaction run. Default: Long.MAX_VALUE
        Parameters:
        maxMergeWidth - maximum number of files in a single compaction run
        Returns:
        the reference to the current options.

      • maxMergeWidth

        public int maxMergeWidth()
        The maximum number of files in a single compaction run. Default: Long.MAX_VALUE
        Returns:
        maximum number of files in a single compaction run

      • setMaxSizeAmplificationPercent

        public CompactionOptionsUniversal setMaxSizeAmplificationPercent​(int maxSizeAmplificationPercent)
        The size amplification is defined as the amount (in percentage) of additional storage needed to store a single byte of data in the database. For example, a size amplification of 2% means that a database that contains 100 bytes of user-data may occupy upto 102 bytes of physical storage. By this definition, a fully compacted database has a size amplification of 0%. Rocksdb uses the following heuristic to calculate size amplification: it assumes that all files excluding the earliest file contribute to the size amplification. Default: 200, which means that a 100 byte database could require upto 300 bytes of storage.
        Parameters:
        maxSizeAmplificationPercent - the amount of additional storage needed (as a percentage) to store a single byte in the database
        Returns:
        the reference to the current options.

      • maxSizeAmplificationPercent

        public int maxSizeAmplificationPercent()
        The size amplification is defined as the amount (in percentage) of additional storage needed to store a single byte of data in the database. For example, a size amplification of 2% means that a database that contains 100 bytes of user-data may occupy upto 102 bytes of physical storage. By this definition, a fully compacted database has a size amplification of 0%. Rocksdb uses the following heuristic to calculate size amplification: it assumes that all files excluding the earliest file contribute to the size amplification. Default: 200, which means that a 100 byte database could require upto 300 bytes of storage.
        Returns:
        the amount of additional storage needed (as a percentage) to store a single byte in the database

      • setCompressionSizePercent

        public CompactionOptionsUniversal setCompressionSizePercent​(int compressionSizePercent)
        If this option is set to be -1 (the default value), all the output files will follow compression type specified. If this option is not negative, we will try to make sure compressed size is just above this value. In normal cases, at least this percentage of data will be compressed. When we are compacting to a new file, here is the criteria whether it needs to be compressed: assuming here are the list of files sorted by generation time: A1...An B1...Bm C1...Ct where A1 is the newest and Ct is the oldest, and we are going to compact B1...Bm, we calculate the total size of all the files as total_size, as well as the total size of C1...Ct as total_C, the compaction output file will be compressed iff total_C / total_size < this percentage Default: -1
        Parameters:
        compressionSizePercent - percentage of size for compression
        Returns:
        the reference to the current options.

      • compressionSizePercent

        public int compressionSizePercent()
        If this option is set to be -1 (the default value), all the output files will follow compression type specified. If this option is not negative, we will try to make sure compressed size is just above this value. In normal cases, at least this percentage of data will be compressed. When we are compacting to a new file, here is the criteria whether it needs to be compressed: assuming here are the list of files sorted by generation time: A1...An B1...Bm C1...Ct where A1 is the newest and Ct is the oldest, and we are going to compact B1...Bm, we calculate the total size of all the files as total_size, as well as the total size of C1...Ct as total_C, the compaction output file will be compressed iff total_C / total_size < this percentage Default: -1
        Returns:
        percentage of size for compression

      • setAllowTrivialMove

        public CompactionOptionsUniversal setAllowTrivialMove​(boolean allowTrivialMove)
        Option to optimize the universal multi level compaction by enabling trivial move for non overlapping files. Default: false
        Parameters:
        allowTrivialMove - true if trivial move is allowed
        Returns:
        the reference to the current options.

      • allowTrivialMove

        public boolean allowTrivialMove()
        Option to optimize the universal multi level compaction by enabling trivial move for non overlapping files. Default: false
        Returns:
        true if trivial move is allowed