mirror of https://github.com/milvus-io/milvus.git
124 lines
3.6 KiB
Go
124 lines
3.6 KiB
Go
// Licensed to the LF AI & Data foundation under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package datacoord
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import (
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"math"
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"sort"
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"github.com/bits-and-blooms/bitset"
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)
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type Sizable interface {
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getSegmentSize() int64
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GetID() int64
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}
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type Knapsack[T Sizable] struct {
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name string
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candidates []T
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}
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func newKnapsack[T Sizable](name string, candidates []T) Knapsack[T] {
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sort.Slice(candidates, func(i, j int) bool {
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if candidates[i].getSegmentSize() != candidates[j].getSegmentSize() {
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return candidates[i].getSegmentSize() > candidates[j].getSegmentSize()
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}
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return candidates[i].GetID() < candidates[j].GetID()
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})
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return Knapsack[T]{
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name: name,
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candidates: candidates,
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}
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}
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func (c *Knapsack[T]) tryPack(size, maxLeftSize, minSegs, maxSegs int64) (bitset.BitSet, int64) {
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selection := bitset.New(uint(len(c.candidates)))
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left := size
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for i, segment := range c.candidates {
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if maxSegs == 0 {
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break
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}
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if segment.getSegmentSize() <= left {
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selection.Set(uint(i))
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left -= segment.getSegmentSize()
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maxSegs--
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}
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}
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nSelections := selection.Count()
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if left > maxLeftSize || nSelections < uint(minSegs) {
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selection.ClearAll()
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left = size
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}
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return *selection, left
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}
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func (c *Knapsack[T]) commit(selection bitset.BitSet) []T {
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var (
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candidates = make([]T, 0, len(c.candidates)-int(selection.Count()))
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returns = make([]T, 0, int(selection.Count()))
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)
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for i, candidate := range c.candidates {
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if selection.Test(uint(i)) {
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returns = append(returns, candidate)
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} else {
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candidates = append(candidates, candidate)
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}
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}
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c.candidates = candidates
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return returns
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}
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// pack packs up to maxSegs segments into a single segment to match the total size given by size.
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// If the remaining size is greater than maxLeftSize, or the number of segments is less than minSegs, return nil.
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// returns the packed segments and the remaining size
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func (c *Knapsack[T]) pack(size, maxLeftSize, minSegs, maxSegs int64) ([]T, int64) {
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selection, left := c.tryPack(size, maxLeftSize, minSegs, maxSegs)
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if selection.Count() == 0 {
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return nil, size
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}
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segs := c.commit(selection)
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return segs, left
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}
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func (c *Knapsack[T]) packWith(size, maxLeftSize, minSegs, maxSegs int64, other Knapsack[T]) ([]T, int64) {
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selection, left := c.tryPack(size, math.MaxInt64, 0, maxSegs)
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if selection.Count() == 0 {
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return nil, size
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}
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numPacked := int64(selection.Count())
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otherSelection, left := other.tryPack(left, maxLeftSize, minSegs-numPacked, maxSegs-numPacked)
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if otherSelection.Count() == 0 {
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// If the original selection already satisfied the requirements, return immediately
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if left < maxLeftSize && selection.Count() >= uint(minSegs) {
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return c.commit(selection), left
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}
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return nil, size
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}
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segs := c.commit(selection)
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otherSegs := other.commit(otherSelection)
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return append(segs, otherSegs...), left
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}
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func newSegmentPacker(name string, candidates []*SegmentInfo) Knapsack[*SegmentInfo] {
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return newKnapsack[*SegmentInfo](name, candidates)
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}
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