65fed52d0b
Since its just the pointer size of the IndexReader that is being accounted for while estimating the RAM needed to execute a search query, get rid of the Size() API in the IndexReader interface.
385 lines
10 KiB
Go
385 lines
10 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// 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 searcher
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import (
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"fmt"
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"math"
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"reflect"
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/search"
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"github.com/blevesearch/bleve/size"
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)
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var reflectStaticSizePhraseSearcher int
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func init() {
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var ps PhraseSearcher
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reflectStaticSizePhraseSearcher = int(reflect.TypeOf(ps).Size())
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}
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type PhraseSearcher struct {
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indexReader index.IndexReader
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mustSearcher *ConjunctionSearcher
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queryNorm float64
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currMust *search.DocumentMatch
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slop int
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terms [][]string
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initialized bool
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}
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func (s *PhraseSearcher) Size() int {
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sizeInBytes := reflectStaticSizePhraseSearcher + size.SizeOfPtr
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if s.mustSearcher != nil {
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sizeInBytes += s.mustSearcher.Size()
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}
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if s.currMust != nil {
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sizeInBytes += s.currMust.Size()
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}
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for _, entry := range s.terms {
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sizeInBytes += size.SizeOfSlice
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for _, entry1 := range entry {
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sizeInBytes += size.SizeOfString + len(entry1)
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}
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}
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return sizeInBytes
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}
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func NewPhraseSearcher(indexReader index.IndexReader, terms []string, field string, options search.SearcherOptions) (*PhraseSearcher, error) {
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// turn flat terms []string into [][]string
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mterms := make([][]string, len(terms))
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for i, term := range terms {
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mterms[i] = []string{term}
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}
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return NewMultiPhraseSearcher(indexReader, mterms, field, options)
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}
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func NewMultiPhraseSearcher(indexReader index.IndexReader, terms [][]string, field string, options search.SearcherOptions) (*PhraseSearcher, error) {
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options.IncludeTermVectors = true
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var termPositionSearchers []search.Searcher
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for _, termPos := range terms {
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if len(termPos) == 1 && termPos[0] != "" {
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// single term
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ts, err := NewTermSearcher(indexReader, termPos[0], field, 1.0, options)
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if err != nil {
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// close any searchers already opened
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for _, ts := range termPositionSearchers {
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_ = ts.Close()
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}
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return nil, fmt.Errorf("phrase searcher error building term searcher: %v", err)
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}
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termPositionSearchers = append(termPositionSearchers, ts)
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} else if len(termPos) > 1 {
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// multiple terms
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var termSearchers []search.Searcher
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for _, term := range termPos {
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if term == "" {
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continue
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}
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ts, err := NewTermSearcher(indexReader, term, field, 1.0, options)
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if err != nil {
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// close any searchers already opened
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for _, ts := range termPositionSearchers {
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_ = ts.Close()
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}
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return nil, fmt.Errorf("phrase searcher error building term searcher: %v", err)
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}
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termSearchers = append(termSearchers, ts)
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}
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disjunction, err := NewDisjunctionSearcher(indexReader, termSearchers, 1, options)
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if err != nil {
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// close any searchers already opened
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for _, ts := range termPositionSearchers {
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_ = ts.Close()
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}
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return nil, fmt.Errorf("phrase searcher error building term position disjunction searcher: %v", err)
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}
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termPositionSearchers = append(termPositionSearchers, disjunction)
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}
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}
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mustSearcher, err := NewConjunctionSearcher(indexReader, termPositionSearchers, options)
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if err != nil {
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// close any searchers already opened
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for _, ts := range termPositionSearchers {
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_ = ts.Close()
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}
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return nil, fmt.Errorf("phrase searcher error building conjunction searcher: %v", err)
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}
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// build our searcher
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rv := PhraseSearcher{
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indexReader: indexReader,
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mustSearcher: mustSearcher,
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terms: terms,
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}
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rv.computeQueryNorm()
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return &rv, nil
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}
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func (s *PhraseSearcher) computeQueryNorm() {
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// first calculate sum of squared weights
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sumOfSquaredWeights := 0.0
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if s.mustSearcher != nil {
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sumOfSquaredWeights += s.mustSearcher.Weight()
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}
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// now compute query norm from this
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s.queryNorm = 1.0 / math.Sqrt(sumOfSquaredWeights)
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// finally tell all the downstream searchers the norm
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if s.mustSearcher != nil {
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s.mustSearcher.SetQueryNorm(s.queryNorm)
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}
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}
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func (s *PhraseSearcher) initSearchers(ctx *search.SearchContext) error {
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err := s.advanceNextMust(ctx)
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if err != nil {
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return err
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}
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s.initialized = true
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return nil
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}
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func (s *PhraseSearcher) advanceNextMust(ctx *search.SearchContext) error {
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var err error
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if s.mustSearcher != nil {
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s.currMust, err = s.mustSearcher.Next(ctx)
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (s *PhraseSearcher) Weight() float64 {
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return s.mustSearcher.Weight()
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}
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func (s *PhraseSearcher) SetQueryNorm(qnorm float64) {
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s.mustSearcher.SetQueryNorm(qnorm)
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}
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func (s *PhraseSearcher) Next(ctx *search.SearchContext) (*search.DocumentMatch, error) {
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if !s.initialized {
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err := s.initSearchers(ctx)
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if err != nil {
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return nil, err
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}
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}
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for s.currMust != nil {
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// check this match against phrase constraints
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rv := s.checkCurrMustMatch(ctx)
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// prepare for next iteration (either loop or subsequent call to Next())
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err := s.advanceNextMust(ctx)
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if err != nil {
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return nil, err
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}
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// if match satisfied phrase constraints return it as a hit
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if rv != nil {
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return rv, nil
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}
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}
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return nil, nil
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}
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// checkCurrMustMatch is soley concerned with determining if the DocumentMatch
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// pointed to by s.currMust (which satisifies the pre-condition searcher)
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// also satisfies the phase constraints. if so, it returns a DocumentMatch
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// for this document, otherwise nil
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func (s *PhraseSearcher) checkCurrMustMatch(ctx *search.SearchContext) *search.DocumentMatch {
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rvftlm := make(search.FieldTermLocationMap, 0)
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freq := 0
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// typically we would expect there to only actually be results in
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// one field, but we allow for this to not be the case
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// but, we note that phrase constraints can only be satisfied within
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// a single field, so we can check them each independently
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for field, tlm := range s.currMust.Locations {
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f, rvtlm := s.checkCurrMustMatchField(ctx, tlm)
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if f > 0 {
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freq += f
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rvftlm[field] = rvtlm
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}
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}
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if freq > 0 {
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// return match
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rv := s.currMust
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rv.Locations = rvftlm
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return rv
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}
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return nil
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}
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// checkCurrMustMatchField is soley concerned with determining if one particular
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// field within the currMust DocumentMatch Locations satisfies the phase
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// constraints (possibly more than once). if so, the number of times it was
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// satisfied, and these locations are returned. otherwise 0 and either
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// a nil or empty TermLocationMap
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func (s *PhraseSearcher) checkCurrMustMatchField(ctx *search.SearchContext, tlm search.TermLocationMap) (int, search.TermLocationMap) {
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paths := findPhrasePaths(0, nil, s.terms, tlm, nil, 0)
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rv := make(search.TermLocationMap, len(s.terms))
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for _, p := range paths {
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p.MergeInto(rv)
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}
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return len(paths), rv
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}
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type phrasePart struct {
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term string
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loc *search.Location
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}
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func (p *phrasePart) String() string {
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return fmt.Sprintf("[%s %v]", p.term, p.loc)
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}
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type phrasePath []*phrasePart
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func (p phrasePath) MergeInto(in search.TermLocationMap) {
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for _, pp := range p {
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in[pp.term] = append(in[pp.term], pp.loc)
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}
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}
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// findPhrasePaths is a function to identify phase matches from a set of known
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// term locations. the implementation is recursive, so care must be taken
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// with arguments and return values.
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//
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// prev - the previous location, nil on first invocation
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// phraseTerms - slice containing the phrase terms themselves
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// may contain empty string as placeholder (don't care)
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// tlm - the Term Location Map containing all relevant term locations
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// offset - the offset from the previous that this next term must match
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// p - the current path being explored (appended to in recursive calls)
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// this is the primary state being built during the traversal
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//
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// returns slice of paths, or nil if invocation did not find any successul paths
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func findPhrasePaths(prevPos uint64, ap search.ArrayPositions, phraseTerms [][]string, tlm search.TermLocationMap, p phrasePath, remainingSlop int) []phrasePath {
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// no more terms
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if len(phraseTerms) < 1 {
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return []phrasePath{p}
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}
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car := phraseTerms[0]
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cdr := phraseTerms[1:]
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// empty term is treated as match (continue)
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if len(car) == 0 || (len(car) == 1 && car[0] == "") {
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nextPos := prevPos + 1
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if prevPos == 0 {
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// if prevPos was 0, don't set it to 1 (as thats not a real abs pos)
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nextPos = 0 // don't advance nextPos if prevPos was 0
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}
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return findPhrasePaths(nextPos, ap, cdr, tlm, p, remainingSlop)
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}
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var rv []phrasePath
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// locations for this term
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for _, carTerm := range car {
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locations := tlm[carTerm]
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for _, loc := range locations {
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if prevPos != 0 && !loc.ArrayPositions.Equals(ap) {
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// if the array positions are wrong, can't match, try next location
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continue
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}
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// compute distance from previous phrase term
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dist := 0
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if prevPos != 0 {
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dist = editDistance(prevPos+1, loc.Pos)
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}
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// if enough slop reamining, continue recursively
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if prevPos == 0 || (remainingSlop-dist) >= 0 {
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// this location works, add it to the path (but not for empty term)
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px := append(p, &phrasePart{term: carTerm, loc: loc})
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rv = append(rv, findPhrasePaths(loc.Pos, loc.ArrayPositions, cdr, tlm, px, remainingSlop-dist)...)
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}
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}
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}
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return rv
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}
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func editDistance(p1, p2 uint64) int {
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dist := int(p1 - p2)
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if dist < 0 {
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return -dist
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}
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return dist
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}
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func (s *PhraseSearcher) Advance(ctx *search.SearchContext, ID index.IndexInternalID) (*search.DocumentMatch, error) {
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if !s.initialized {
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err := s.initSearchers(ctx)
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if err != nil {
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return nil, err
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}
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}
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if s.currMust != nil {
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if s.currMust.IndexInternalID.Compare(ID) >= 0 {
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return s.Next(ctx)
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}
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ctx.DocumentMatchPool.Put(s.currMust)
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}
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if s.currMust == nil {
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return nil, nil
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}
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var err error
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s.currMust, err = s.mustSearcher.Advance(ctx, ID)
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if err != nil {
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return nil, err
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}
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return s.Next(ctx)
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}
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func (s *PhraseSearcher) Count() uint64 {
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// for now return a worst case
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return s.mustSearcher.Count()
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}
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func (s *PhraseSearcher) Close() error {
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if s.mustSearcher != nil {
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err := s.mustSearcher.Close()
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (s *PhraseSearcher) Min() int {
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return 0
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}
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func (s *PhraseSearcher) DocumentMatchPoolSize() int {
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return s.mustSearcher.DocumentMatchPoolSize() + 1
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}
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