github.com/matrixorigin/matrixone@v1.2.0/pkg/sql/plan/shuffle_algo.go (about)

     1  // Copyright 2022 Matrix Origin
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package plan
    16  
    17  import (
    18  	pb "github.com/matrixorigin/matrixone/pkg/pb/statsinfo"
    19  )
    20  
    21  func NewShuffleRange(isString bool) *pb.ShuffleRange {
    22  	return &pb.ShuffleRange{IsStrType: isString}
    23  }
    24  
    25  func ShuffleRangeReEvalUnsigned(ranges []float64, k2 int, nullCnt int64, tableCnt int64) []uint64 {
    26  	k1 := len(ranges)
    27  	if k2 > k1/2 {
    28  		return nil
    29  	}
    30  	result := make([]uint64, k2-1)
    31  	if tableCnt/int64(k2) <= nullCnt {
    32  		result[0] = uint64(ranges[0])
    33  		for i := 1; i <= k2-2; i++ {
    34  			result[i] = uint64(ranges[(i)*(k1-1)/(k2-1)])
    35  		}
    36  	} else {
    37  		for i := 0; i <= k2-2; i++ {
    38  			result[i] = uint64(ranges[(i+1)*k1/k2-1])
    39  		}
    40  	}
    41  	return result
    42  }
    43  
    44  func ShuffleRangeReEvalSigned(ranges []float64, k2 int, nullCnt int64, tableCnt int64) []int64 {
    45  	k1 := len(ranges)
    46  	if k2 > k1/2 {
    47  		return nil
    48  	}
    49  	result := make([]int64, k2-1)
    50  	if tableCnt/int64(k2) <= nullCnt {
    51  		result[0] = int64(ranges[0])
    52  		for i := 1; i <= k2-2; i++ {
    53  			result[i] = int64(ranges[(i)*(k1-1)/(k2-1)])
    54  		}
    55  	} else {
    56  		for i := 0; i <= k2-2; i++ {
    57  			result[i] = int64(ranges[(i+1)*k1/k2-1])
    58  		}
    59  	}
    60  	return result
    61  }