Leveled Compaction Strategy | Apache Cassandra Documentation

The idea of LeveledCompactionStrategy (LCS) is that all sstables are put into different levels where we guarantee that no overlapping sstables are in the same level. By overlapping we mean that the first/last token of a single sstable are never overlapping with other sstables. This means that for a SELECT we will only have to look for the partition key in a single sstable per level. Each level is 10x the size of the previous one and each sstable is 160MB by default. L0 is where sstables are streamed/flushed - no overlap guarantees are given here. When picking compaction candidates we have to make sure that the compaction does not create overlap in the target level. This is done by always including all overlapping sstables in the next level. For example if we select an sstable in L3, we need to guarantee that we pick all overlapping sstables in L4 and make sure that no currently ongoing compactions will create overlap if we start that compaction. We can start many parallel compactions i

The idea of LeveledCompactionStrategy (LCS) is that all sstables are put into different levels where we guarantee that no overlapping sstables are in the same level. By overlapping we mean that the first/last token of a single sstable are never overlapping with other sstables. This means that for a SELECT we will only have to look for the partition key in a single sstable per level. Each level is 10x the size of the previous one and each sstable is 160MB by default. L0 is where sstables are streamed/flushed - no overlap guarantees are given here. When picking compaction candidates we have to m