// key顺序扫描，常用于数据导出、附近搜索
// 返回的key是面向用户的key，而非内部结构的raw_key
func (l *LevelRedis) KeyEnumerate(seek []byte, direction IterDirection, fn func(i int, key, keytype, value []byte, quit *bool)) {
var iter *gorocks.Iterator
if l.snap != nil {
iter = l.db.NewIterator(l.ro)
} else {
ro := gorocks.NewReadOptions()
ro.SetFillCache(false)
defer ro.Close()
iter = l.db.NewIterator(ro)
}
defer iter.Close()
minkey := joinStringBytes(KEY_PREFIX, SEP_LEFT, string(seek))
maxkey := []byte{MAXBYTE}
prefix := joinStringBytes(KEY_PREFIX, SEP_LEFT)
l.Enumerate(iter, minkey, maxkey, direction, func(i int, key, value []byte, quit *bool) {
if !bytes.HasPrefix(key, prefix) {
*quit = true
return
}
left := bytes.Index(key, []byte(SEP_LEFT))
right := bytes.LastIndex(key, []byte(SEP_RIGHT))
if left == -1 || right == -1 {
return // just skip
}
fn(i, key[left+1:right], key[right+1:], value, quit)
})
}
// snapshot，快照模式
func NewLevelRedis(db *gorocks.DB, snapshot bool) (l *LevelRedis) {
l = &LevelRedis{}
l.db = db
l.ro = gorocks.NewReadOptions()
if snapshot {
l.snap = l.db.NewSnapshot() //必须调用Close()释放snap
l.ro.SetSnapshot(l.snap)
l.ro.SetFillCache(false)
l.wo = nil // snapshot模式下禁止写入数据
} else {
l.wo = gorocks.NewWriteOptions()
}
l.counters = map[string]int64{"get": 0, "set": 0, "batch": 0, "del": 0, "enum": 0, "lru_hit": 0, "lru_miss": 0}
l.lstring = NewLevelString(l)
l.g = newGlobal(l)
l.lruCache = lru.NewLRUCache(lruCacheSize)
l.mus = make([]sync.Mutex, objCacheCreateThread)
// 初始化最大的key，对于Enumerate从后面开始扫描key非常重要
// 使iter.Seek(key)必定Valid=true
if !snapshot {
maxkey := []byte{MAXBYTE}
l.RawSet(maxkey, nil)
}
return
}
func (l *LevelRedis) RangeEnumerate(min, max []byte, direction IterDirection, fn func(i int, key, value []byte, quit *bool)) {
var iter *gorocks.Iterator
if l.snap != nil {
iter = l.db.NewIterator(l.ro)
} else {
ro := gorocks.NewReadOptions()
ro.SetFillCache(false)
defer ro.Close()
iter = l.db.NewIterator(ro)
}
defer iter.Close()
l.Enumerate(iter, min, max, direction, fn)
}