milvus/internal/kv/rocksdb/RocksIterator.go
2021-12-30 20:08:15 +08:00

109 lines
2.9 KiB
Go

package rocksdbkv
import (
"runtime"
"github.com/milvus-io/milvus/internal/log"
"github.com/tecbot/gorocksdb"
)
/**
* A wrapper of go rocksdb iterator
* it helps on 1) reserve the upperBound array to avoid garbage collection
* 2) do a leakage check of iterator
*/
type RocksIterator struct {
it *gorocksdb.Iterator
upperBound []byte
close bool
}
func NewRocksIterator(db *gorocksdb.DB, opts *gorocksdb.ReadOptions) *RocksIterator {
iter := db.NewIterator(opts)
it := &RocksIterator{iter, nil, false}
runtime.SetFinalizer(it, func(rocksit *RocksIterator) {
if !rocksit.close {
log.Error("iterator is leaking.. please check")
}
})
return it
}
func NewRocksIteratorWithUpperBound(db *gorocksdb.DB, upperBoundString string, opts *gorocksdb.ReadOptions) *RocksIterator {
upperBound := []byte(upperBoundString)
opts.SetIterateUpperBound(upperBound)
iter := db.NewIterator(opts)
it := &RocksIterator{iter, upperBound, false}
runtime.SetFinalizer(it, func(rocksit *RocksIterator) {
if !rocksit.close {
log.Error("iterator is leaking.. please check")
}
})
return it
}
// Valid returns false only when an Iterator has iterated past either the
// first or the last key in the database.
func (iter *RocksIterator) Valid() bool {
return iter.it.Valid()
}
// ValidForPrefix returns false only when an Iterator has iterated past the
// first or the last key in the database or the specified prefix.
func (iter *RocksIterator) ValidForPrefix(prefix []byte) bool {
return iter.it.ValidForPrefix(prefix)
}
// Key returns the key the iterator currently holds.
func (iter *RocksIterator) Key() *gorocksdb.Slice {
return iter.it.Key()
}
// Value returns the value in the database the iterator currently holds.
func (iter *RocksIterator) Value() *gorocksdb.Slice {
return iter.it.Value()
}
// Next moves the iterator to the next sequential key in the database.
func (iter *RocksIterator) Next() {
iter.it.Next()
}
// Prev moves the iterator to the previous sequential key in the database.
func (iter *RocksIterator) Prev() {
iter.it.Prev()
}
// SeekToFirst moves the iterator to the first key in the database.
func (iter *RocksIterator) SeekToFirst() {
iter.it.SeekToFirst()
}
// SeekToLast moves the iterator to the last key in the database.
func (iter *RocksIterator) SeekToLast() {
iter.it.SeekToLast()
}
// Seek moves the iterator to the position greater than or equal to the key.
func (iter *RocksIterator) Seek(key []byte) {
iter.it.Seek(key)
}
// SeekForPrev moves the iterator to the last key that less than or equal
// to the target key, in contrast with Seek.
func (iter *RocksIterator) SeekForPrev(key []byte) {
iter.it.SeekForPrev(key)
}
// Err returns nil if no errors happened during iteration, or the actual
// error otherwise.
func (iter *RocksIterator) Err() error {
return iter.it.Err()
}
// Close closes the iterator.
func (iter *RocksIterator) Close() {
iter.close = true
iter.it.Close()
}