org.apache.paimon.mergetree.compact

Class UniversalCompaction

java.lang.Object

org.apache.paimon.mergetree.compact.UniversalCompaction

All Implemented Interfaces:

CompactStrategy

public class UniversalCompaction
extends Object
implements CompactStrategy

Universal Compaction Style is a compaction style, targeting the use cases requiring lower write amplification, trading off read amplification and space amplification.

See RocksDb Universal-Compaction: https://github.com/facebook/rocksdb/wiki/Universal-Compaction.

Constructor Summary

Constructors

Constructor and Description
UniversalCompaction(int maxSizeAmp, int sizeRatio, int numRunCompactionTrigger)
UniversalCompaction(int maxSizeAmp, int sizeRatio, int numRunCompactionTrigger, java.time.Duration opCompactionInterval)

Method Summary

Modifier and Type	Method and Description
Optional<CompactUnit>	pick(int numLevels, List<LevelSortedRun> runs) Pick compaction unit from runs.
CompactUnit	pickForSizeRatio(int maxLevel, List<LevelSortedRun> runs, int candidateCount, boolean forcePick)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.paimon.mergetree.compact.CompactStrategy

pickFullCompaction

Constructor Detail

UniversalCompaction

public UniversalCompaction(int maxSizeAmp,
                           int sizeRatio,
                           int numRunCompactionTrigger)

UniversalCompaction

public UniversalCompaction(int maxSizeAmp,
                           int sizeRatio,
                           int numRunCompactionTrigger,
                           @Nullable
                           java.time.Duration opCompactionInterval)

Method Detail

pick

public Optional<CompactUnit> pick(int numLevels,
                                  List<LevelSortedRun> runs)

Description copied from interface: CompactStrategy

Pick compaction unit from runs.

• compaction is runs-based, not file-based.
• level 0 is special, one run per file; all other levels are one run per level.
• compaction is sequential from small level to large level.

Specified by:

pick in interface CompactStrategy

pickForSizeRatio

public CompactUnit pickForSizeRatio(int maxLevel,
                                    List<LevelSortedRun> runs,
                                    int candidateCount,
                                    boolean forcePick)