github.com/whtcorpsinc/milevadb-prod@v0.0.0-20211104133533-f57f4be3b597/allegrosql/partition_prune.go (about)

     1  // Copyright 2020 WHTCORPS INC, Inc.
     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  // // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // See the License for the specific language governing permissions and
    11  // limitations under the License.
    12  
    13  package embedded
    14  
    15  import (
    16  	"github.com/whtcorpsinc/BerolinaSQL/perceptron"
    17  	"github.com/whtcorpsinc/milevadb/causet"
    18  	"github.com/whtcorpsinc/milevadb/memex"
    19  	"github.com/whtcorpsinc/milevadb/stochastikctx"
    20  	"github.com/whtcorpsinc/milevadb/types"
    21  )
    22  
    23  // PartitionPruning finds all used partitions according to query conditions, it will
    24  // return nil if condition match none of partitions. The return value is a array of the
    25  // idx in the partition definitions array, use pi.Definitions[idx] to get the partition ID
    26  func PartitionPruning(ctx stochastikctx.Context, tbl causet.PartitionedBlock, conds []memex.Expression, partitionNames []perceptron.CIStr,
    27  	columns []*memex.DeferredCauset, names types.NameSlice) ([]int, error) {
    28  	s := partitionProcessor{}
    29  	pi := tbl.Meta().Partition
    30  	switch pi.Type {
    31  	case perceptron.PartitionTypeHash:
    32  		return s.pruneHashPartition(ctx, tbl, partitionNames, conds, columns, names)
    33  	case perceptron.PartitionTypeRange:
    34  		rangeOr, err := s.pruneRangePartition(ctx, pi, tbl, conds, columns, names)
    35  		if err != nil {
    36  			return nil, err
    37  		}
    38  		ret := s.convertToIntSlice(rangeOr, pi, partitionNames)
    39  		return ret, nil
    40  	}
    41  	return []int{FullRange}, nil
    42  }