Struct NonOverlapSubLevelPicker 

pub struct NonOverlapSubLevelPicker {
    min_compaction_bytes: u64,
    max_compaction_bytes: u64,
    min_expected_level_count: usize,
    max_file_count: u64,
    overlap_strategy: Arc<dyn OverlapStrategy>,
    enable_check_task_level_overlap: bool,
    max_expected_level_count: usize,
    enable_optimize_l0_interval_selection: bool,
}

Fields

min_compaction_bytes: u64

max_compaction_bytes: u64

min_expected_level_count: usize

max_file_count: u64

overlap_strategy: Arc<dyn OverlapStrategy>

enable_check_task_level_overlap: bool

max_expected_level_count: usize

enable_optimize_l0_interval_selection: bool

Implementations

impl NonOverlapSubLevelPicker

fn select_intervals<'a>( &self, l0: &'a [Level], level_handler: &LevelHandler, ) -> Option<&'a [SstableInfo]>

Pick the sub-level used to iterate candidate intervals:

• ignore overlapping sub-levels
• without optimization: choose the first non-overlapping sub-level
• with optimization: choose the non-overlapping sub-level with the most non-pending sstables (then by total file count, then by index) Returns None when no non-overlapping sub-level exists.

pub fn new( min_compaction_bytes: u64, max_compaction_bytes: u64, min_expected_level_count: usize, max_file_count: u64, overlap_strategy: Arc<dyn OverlapStrategy>, enable_check_task_level_overlap: bool, max_expected_level_count: usize, enable_optimize_l0_interval_selection: bool, ) -> Self

fn pick_sub_level( &self, levels: &[Level], level_handler: &LevelHandler, key_range: &KeyRange, ) -> Option<SubLevelSstables>

Selects overlapping SSTs across multiple L0 sub-levels for a given key range.

For each possible target sub-level, expands backwards (toward older sub-levels) to collect overlapping SSTs. Returns the expansion covering the most sub-levels within configured size and count limits.

Arguments

• levels - L0 sub-levels ordered from oldest to newest
• level_handler - Tracks which SSTs are currently being compacted
• key_range - Initial key range to search for overlaps

Returns

Some with selected SSTs grouped by sub-level, or None if no valid selection exists.

pub fn pick_l0_multi_non_overlap_level( &self, l0: &[Level], level_handler: &LevelHandler, ) -> Vec<SubLevelSstables>

Generates multiple compaction task candidates from L0 sub-levels.

Iterates through candidate SSTs from a selected interval sub-level, calls pick_sub_level for each to form tasks, then classifies and sorts them by priority (“expected” tasks before “unexpected” ones).

Arguments

• l0 - L0 sub-levels ordered from oldest to newest
• level_handler - Tracks which SSTs are currently being compacted

Returns

Sorted vector of task candidates, or empty if insufficient sub-levels exist. Tasks are marked “expected” when satisfying configured size and level count thresholds.

fn verify_task_level_overlap(&self, ret: &SubLevelSstables, levels: &[Level])