b55c9043b9
While researching an observed performance issue with wildcard queries, it was observed that the LiteralPrefix() method on the regexp.Regexp struct did not always behave as expected. In particular, when the pattern starts with ^, AND involves some backtracking, the LiteralPrefix() seems to always be the empty string. The side-effect of this is that we rely on having a helpful prefix, to reduce the number of terms in the term dictionary that need to be visited. This change now makes the searcher enforce start/end on the term directly, by using FindStringIndex() instead of Match(). Next, we also modified WildcardQuery and RegexpQuery to no longer include the ^ and $ modifiers. Documentation was also udpated to instruct users that they should not include the ^ and $ modifiers in their patterns.
107 lines
2.6 KiB
Go
107 lines
2.6 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 query
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import (
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"regexp"
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"strings"
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/mapping"
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"github.com/blevesearch/bleve/search"
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"github.com/blevesearch/bleve/search/searcher"
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)
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var wildcardRegexpReplacer = strings.NewReplacer(
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// characters in the wildcard that must
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// be escaped in the regexp
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"+", `\+`,
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"(", `\(`,
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")", `\)`,
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"^", `\^`,
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"$", `\$`,
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".", `\.`,
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"{", `\{`,
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"}", `\}`,
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"[", `\[`,
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"]", `\]`,
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`|`, `\|`,
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`\`, `\\`,
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// wildcard characters
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"*", ".*",
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"?", ".")
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type WildcardQuery struct {
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Wildcard string `json:"wildcard"`
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FieldVal string `json:"field,omitempty"`
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BoostVal *Boost `json:"boost,omitempty"`
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compiled *regexp.Regexp
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}
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// NewWildcardQuery creates a new Query which finds
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// documents containing terms that match the
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// specified wildcard. In the wildcard pattern '*'
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// will match any sequence of 0 or more characters,
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// and '?' will match any single character.
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func NewWildcardQuery(wildcard string) *WildcardQuery {
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return &WildcardQuery{
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Wildcard: wildcard,
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}
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}
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func (q *WildcardQuery) SetBoost(b float64) {
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boost := Boost(b)
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q.BoostVal = &boost
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}
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func (q *WildcardQuery) Boost() float64 {
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return q.BoostVal.Value()
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}
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func (q *WildcardQuery) SetField(f string) {
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q.FieldVal = f
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}
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func (q *WildcardQuery) Field() string {
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return q.FieldVal
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}
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func (q *WildcardQuery) Searcher(i index.IndexReader, m mapping.IndexMapping, options search.SearcherOptions) (search.Searcher, error) {
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field := q.FieldVal
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if q.FieldVal == "" {
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field = m.DefaultSearchField()
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}
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if q.compiled == nil {
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var err error
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q.compiled, err = q.convertToRegexp()
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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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return searcher.NewRegexpSearcher(i, q.compiled, field, q.BoostVal.Value(), options)
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}
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func (q *WildcardQuery) Validate() error {
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var err error
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q.compiled, err = q.convertToRegexp()
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return err
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}
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func (q *WildcardQuery) convertToRegexp() (*regexp.Regexp, error) {
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regexpString := wildcardRegexpReplacer.Replace(q.Wildcard)
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return regexp.Compile(regexpString)
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}
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