github.com/m3db/m3@v1.5.0/src/query/functions/binary/or.go (about)

     1  // Copyright (c) 2018 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package binary
    22  
    23  import (
    24  	"math"
    25  
    26  	"github.com/m3db/m3/src/query/block"
    27  	"github.com/m3db/m3/src/query/executor/transform"
    28  	"github.com/m3db/m3/src/query/models"
    29  )
    30  
    31  // OrType uses all values from left hand side, and appends values from the
    32  // right hand side which do not have corresponding tags on the right.
    33  const OrType = "or"
    34  
    35  func makeOrBlock(
    36  	queryCtx *models.QueryContext,
    37  	lMeta, rMeta block.Metadata,
    38  	lIter, rIter block.StepIter,
    39  	controller *transform.Controller,
    40  	matching VectorMatching,
    41  ) (block.Block, error) {
    42  	if !matching.Set {
    43  		return nil, errNoMatching
    44  	}
    45  
    46  	lSeriesMetas := lIter.SeriesMeta()
    47  	lMeta, lSeriesMetas = removeNameTags(lMeta, lSeriesMetas)
    48  	lMeta, lSeriesMetas = removeNameTags(lMeta, lSeriesMetas)
    49  
    50  	rSeriesMetas := rIter.SeriesMeta()
    51  	rMeta, rSeriesMetas = removeNameTags(rMeta, rSeriesMetas)
    52  
    53  	meta, lSeriesMetas, rSeriesMetas, err := combineMetaAndSeriesMeta(
    54  		lMeta,
    55  		rMeta,
    56  		lSeriesMetas,
    57  		rSeriesMetas,
    58  	)
    59  
    60  	if err != nil {
    61  		return nil, err
    62  	}
    63  
    64  	indices, combinedSeriesMeta := mergeIndices(
    65  		matching,
    66  		lSeriesMetas,
    67  		rSeriesMetas,
    68  	)
    69  
    70  	builder, err := controller.BlockBuilder(queryCtx, meta, combinedSeriesMeta)
    71  	if err != nil {
    72  		return nil, err
    73  	}
    74  
    75  	if err = builder.AddCols(lIter.StepCount()); err != nil {
    76  		return nil, err
    77  	}
    78  
    79  	values := make([]float64, len(combinedSeriesMeta))
    80  	for index := 0; lIter.Next(); index++ {
    81  		if !rIter.Next() {
    82  			return nil, errRExhausted
    83  		}
    84  
    85  		lStep := lIter.Current()
    86  		lValues := lStep.Values()
    87  		copy(values, lValues)
    88  		rStep := rIter.Current()
    89  		rValues := rStep.Values()
    90  		for iterIndex, valueIndex := range indices {
    91  			if valueIndex >= len(lValues) {
    92  				values[valueIndex] = rValues[iterIndex]
    93  			} else if math.IsNaN(values[valueIndex]) {
    94  				values[valueIndex] = rValues[iterIndex]
    95  			}
    96  		}
    97  
    98  		if err := builder.AppendValues(index, values); err != nil {
    99  			return nil, err
   100  		}
   101  	}
   102  
   103  	if err = lIter.Err(); err != nil {
   104  		return nil, err
   105  	}
   106  
   107  	if rIter.Next() {
   108  		return nil, errLExhausted
   109  	}
   110  
   111  	if err = rIter.Err(); err != nil {
   112  		return nil, err
   113  	}
   114  
   115  	return builder.Build(), nil
   116  }
   117  
   118  // mergeIndices returns a slice that maps rhs series to lhs series.
   119  //
   120  // NB(arnikola): if the series in the rhs does not exist in the lhs, it is
   121  // added after all lhs series have been added.
   122  // This function also combines the series metadatas for the entire block.
   123  func mergeIndices(
   124  	matching VectorMatching,
   125  	lhs, rhs []block.SeriesMeta,
   126  ) ([]int, []block.SeriesMeta) {
   127  	idFunction := hashFunc(matching.On, matching.MatchingLabels...)
   128  	// The set of signatures for the left-hand side.
   129  	leftSigs := make(map[uint64]int, len(lhs))
   130  	for i, meta := range lhs {
   131  		l := idFunction(meta.Tags)
   132  		leftSigs[l] = i
   133  	}
   134  
   135  	rIndices := make([]int, len(rhs))
   136  	rIndex := len(lhs)
   137  	for i, meta := range rhs {
   138  		// If there's no matching entry in the left-hand side Vector,
   139  		// add the sample.
   140  		r := idFunction(meta.Tags)
   141  		if matchingIndex, ok := leftSigs[r]; !ok {
   142  			rIndices[i] = rIndex
   143  			rIndex++
   144  			lhs = append(lhs, meta)
   145  		} else {
   146  			rIndices[i] = matchingIndex
   147  		}
   148  	}
   149  
   150  	return rIndices, lhs
   151  }