github.com/m3db/m3@v1.5.0/src/query/functions/binary/unless.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/functions/utils"
    29  	"github.com/m3db/m3/src/query/models"
    30  )
    31  
    32  // UnlessType uses all values from lhs which do not exist in rhs
    33  const UnlessType = "unless"
    34  
    35  func makeUnlessBlock(
    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  
    49  	rSeriesMetas := rIter.SeriesMeta()
    50  	rMeta, rSeriesMetas = removeNameTags(rMeta, rSeriesMetas)
    51  
    52  	// NB: need to flatten metadata for cases where
    53  	// e.g. lhs: common tags {a:b}, series tags: {c:d}, {e:f}
    54  	// e.g. rhs: common tags {c:d}, series tags: {a:b}, {e:f}
    55  	// If not flattened before calculating distinct values,
    56  	// both series on lhs would be added
    57  	lSeriesMetas = utils.FlattenMetadata(lMeta, lSeriesMetas)
    58  	rSeriesMetas = utils.FlattenMetadata(rMeta, rSeriesMetas)
    59  	indices := matchingIndices(matching, lSeriesMetas, rSeriesMetas)
    60  
    61  	lMeta.ResultMetadata = lMeta.ResultMetadata.
    62  		CombineMetadata(rMeta.ResultMetadata)
    63  
    64  	builder, err := controller.BlockBuilder(queryCtx, lMeta, lSeriesMetas)
    65  	if err != nil {
    66  		return nil, err
    67  	}
    68  
    69  	if err = builder.AddCols(lIter.StepCount()); err != nil {
    70  		return nil, err
    71  	}
    72  
    73  	for index := 0; lIter.Next(); index++ {
    74  		if !rIter.Next() {
    75  			return nil, errRExhausted
    76  		}
    77  
    78  		lStep := lIter.Current()
    79  		lValues := lStep.Values()
    80  		rStep := rIter.Current()
    81  		rValues := rStep.Values()
    82  		for _, indexMatcher := range indices {
    83  			if !math.IsNaN(rValues[indexMatcher.rhsIndex]) {
    84  				lValues[indexMatcher.lhsIndex] = math.NaN()
    85  			}
    86  		}
    87  
    88  		if err := builder.AppendValues(index, lValues); err != nil {
    89  			return nil, err
    90  		}
    91  	}
    92  
    93  	if err = lIter.Err(); err != nil {
    94  		return nil, err
    95  	}
    96  
    97  	if rIter.Next() {
    98  		return nil, errLExhausted
    99  	}
   100  
   101  	if err = rIter.Err(); err != nil {
   102  		return nil, err
   103  	}
   104  
   105  	return builder.Build(), nil
   106  }
   107  
   108  // matchingIndices returns a slice representing which index in the lhs the rhs
   109  // series maps to. If it does not map to an existing index, this is set to -1.
   110  func matchingIndices(
   111  	matching VectorMatching,
   112  	lhs, rhs []block.SeriesMeta,
   113  ) []indexMatcher {
   114  	idFunction := hashFunc(matching.On, matching.MatchingLabels...)
   115  	// The set of signatures for the left-hand side.
   116  	leftSigs := make(map[uint64]int, len(lhs))
   117  	for idx, meta := range lhs {
   118  		leftSigs[idFunction(meta.Tags)] = idx
   119  	}
   120  
   121  	rhsIndices := make([]indexMatcher, 0, len(rhs))
   122  	for i, rs := range rhs {
   123  		// If this series matches a series on the lhs, add its index.
   124  		id := idFunction(rs.Tags)
   125  		if lhsIndex, ok := leftSigs[id]; ok {
   126  			matcher := indexMatcher{
   127  				lhsIndex: lhsIndex,
   128  				rhsIndex: i,
   129  			}
   130  
   131  			rhsIndices = append(rhsIndices, matcher)
   132  		}
   133  	}
   134  
   135  	return rhsIndices[:len(rhsIndices)]
   136  }