Jeremy Tregunna
6fc3be617d
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Adds a complete LSM-based storage engine with these features: - Single-writer based architecture for the storage engine - WAL for durability, and hey it's configurable - MemTable with skip list implementation for fast read/writes - SSTable with block-based structure for on-disk level-based storage - Background compaction with tiered strategy - ACID transactions - Good documentation (I hope)
77 lines
1.9 KiB
Go
77 lines
1.9 KiB
Go
package compaction
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import (
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"bytes"
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"fmt"
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"github.com/jer/kevo/pkg/sstable"
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)
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// SSTableInfo represents metadata about an SSTable file
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type SSTableInfo struct {
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// Path of the SSTable file
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Path string
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// Level number (0 to N)
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Level int
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// Sequence number for the file within its level
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Sequence uint64
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// Timestamp when the file was created
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Timestamp int64
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// Approximate size of the file in bytes
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Size int64
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// Estimated key count (may be approximate)
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KeyCount int
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// First key in the SSTable
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FirstKey []byte
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// Last key in the SSTable
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LastKey []byte
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// Reader for the SSTable
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Reader *sstable.Reader
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}
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// Overlaps checks if this SSTable's key range overlaps with another SSTable
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func (s *SSTableInfo) Overlaps(other *SSTableInfo) bool {
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// If either SSTable has no keys, they don't overlap
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if len(s.FirstKey) == 0 || len(s.LastKey) == 0 ||
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len(other.FirstKey) == 0 || len(other.LastKey) == 0 {
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return false
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}
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// Check for overlap: not (s ends before other starts OR s starts after other ends)
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// s.LastKey < other.FirstKey || s.FirstKey > other.LastKey
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return !(bytes.Compare(s.LastKey, other.FirstKey) < 0 ||
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bytes.Compare(s.FirstKey, other.LastKey) > 0)
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}
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// KeyRange returns a string representation of the key range in this SSTable
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func (s *SSTableInfo) KeyRange() string {
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return fmt.Sprintf("[%s, %s]",
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string(s.FirstKey), string(s.LastKey))
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}
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// String returns a string representation of the SSTable info
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func (s *SSTableInfo) String() string {
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return fmt.Sprintf("L%d-%06d-%020d.sst Size:%d Keys:%d Range:%s",
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s.Level, s.Sequence, s.Timestamp, s.Size, s.KeyCount, s.KeyRange())
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}
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// CompactionTask represents a set of SSTables to be compacted
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type CompactionTask struct {
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// Input SSTables to compact, grouped by level
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InputFiles map[int][]*SSTableInfo
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// Target level for compaction output
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TargetLevel int
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// Output file path template
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OutputPathTemplate string
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}
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