bourdon
ae87c38776
- Core engine with MemTable, SST, WAL - B+Tree indexing for SST files - Leveled compaction strategy - Multi-table database management - Schema validation and secondary indexes - Query builder with complex conditions - Web UI with HTMX for data visualization - Command-line tools for diagnostics
142 lines
2.4 KiB
Go
142 lines
2.4 KiB
Go
package memtable
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import (
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"sort"
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"sync"
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)
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// MemTable 内存表
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type MemTable struct {
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data map[int64][]byte // key -> value
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keys []int64 // 排序的 keys
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size int64 // 数据大小
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mu sync.RWMutex
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}
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// New 创建 MemTable
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func New() *MemTable {
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return &MemTable{
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data: make(map[int64][]byte),
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keys: make([]int64, 0),
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size: 0,
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}
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}
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// Put 插入数据
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func (m *MemTable) Put(key int64, value []byte) {
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m.mu.Lock()
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defer m.mu.Unlock()
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// 检查是否已存在
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if _, exists := m.data[key]; !exists {
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m.keys = append(m.keys, key)
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// 保持 keys 有序
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sort.Slice(m.keys, func(i, j int) bool {
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return m.keys[i] < m.keys[j]
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})
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}
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m.data[key] = value
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m.size += int64(len(value))
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}
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// Get 查询数据
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func (m *MemTable) Get(key int64) ([]byte, bool) {
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m.mu.RLock()
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defer m.mu.RUnlock()
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value, exists := m.data[key]
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return value, exists
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}
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// Size 获取大小
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func (m *MemTable) Size() int64 {
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m.mu.RLock()
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defer m.mu.RUnlock()
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return m.size
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}
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// Count 获取条目数量
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func (m *MemTable) Count() int {
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m.mu.RLock()
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defer m.mu.RUnlock()
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return len(m.data)
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}
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// Keys 获取所有 keys 的副本（已排序）
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func (m *MemTable) Keys() []int64 {
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m.mu.RLock()
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defer m.mu.RUnlock()
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// 返回副本以避免并发问题
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keysCopy := make([]int64, len(m.keys))
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copy(keysCopy, m.keys)
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return keysCopy
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}
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// Iterator 迭代器
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type Iterator struct {
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mt *MemTable
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index int
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}
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// NewIterator 创建迭代器
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func (m *MemTable) NewIterator() *Iterator {
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m.mu.RLock()
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defer m.mu.RUnlock()
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return &Iterator{
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mt: m,
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index: -1,
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}
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}
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// Next 移动到下一个
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func (it *Iterator) Next() bool {
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it.mt.mu.RLock()
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defer it.mt.mu.RUnlock()
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it.index++
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return it.index < len(it.mt.keys)
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}
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// Key 当前 key
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func (it *Iterator) Key() int64 {
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it.mt.mu.RLock()
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defer it.mt.mu.RUnlock()
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if it.index < 0 || it.index >= len(it.mt.keys) {
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return 0
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}
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return it.mt.keys[it.index]
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}
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// Value 当前 value
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func (it *Iterator) Value() []byte {
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it.mt.mu.RLock()
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defer it.mt.mu.RUnlock()
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if it.index < 0 || it.index >= len(it.mt.keys) {
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return nil
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}
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key := it.mt.keys[it.index]
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return it.mt.data[key]
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}
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// Reset 重置迭代器
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func (it *Iterator) Reset() {
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it.index = -1
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}
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// Clear 清空 MemTable
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func (m *MemTable) Clear() {
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m.mu.Lock()
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defer m.mu.Unlock()
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m.data = make(map[int64][]byte)
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m.keys = make([]int64, 0)
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m.size = 0
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}
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