131 lines
4.1 KiB
Go
131 lines
4.1 KiB
Go
// Copyright (c) 2018 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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"context"
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"fmt"
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"github.com/blevesearch/bleve/v2/search"
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index "github.com/blevesearch/bleve_index_api"
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)
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// DisjunctionMaxClauseCount is a compile time setting that applications can
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// adjust to non-zero value to cause the DisjunctionSearcher to return an
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// error instead of exeucting searches when the size exceeds this value.
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var DisjunctionMaxClauseCount = 0
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// DisjunctionHeapTakeover is a compile time setting that applications can
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// adjust to control when the DisjunctionSearcher will switch from a simple
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// slice implementation to a heap implementation.
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var DisjunctionHeapTakeover = 10
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func NewDisjunctionSearcher(ctx context.Context, indexReader index.IndexReader,
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qsearchers []search.Searcher, min float64, options search.SearcherOptions) (
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search.Searcher, error) {
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return newDisjunctionSearcher(ctx, indexReader, qsearchers, min, options, true)
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}
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func optionsDisjunctionOptimizable(options search.SearcherOptions) bool {
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rv := options.Score == "none" && !options.IncludeTermVectors
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return rv
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}
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func newDisjunctionSearcher(ctx context.Context, indexReader index.IndexReader,
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qsearchers []search.Searcher, min float64, options search.SearcherOptions,
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limit bool) (search.Searcher, error) {
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var disjOverKNN bool
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if ctx != nil {
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disjOverKNN, _ = ctx.Value(search.IncludeScoreBreakdownKey).(bool)
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}
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if disjOverKNN {
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// The KNN Searcher optimization is a necessary pre-req for the KNN Searchers,
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// not an optional optimization like for, say term searchers.
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// It's an optimization to repeat search an open vector index when applicable,
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// rather than individually opening and searching a vector index.
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err := optimizeKNN(ctx, indexReader, qsearchers)
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if err != nil {
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return nil, err
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}
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} else {
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// attempt the "unadorned" disjunction optimization only when we
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// do not need extra information like freq-norm's or term vectors
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// and the requested min is simple
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if len(qsearchers) > 1 && min <= 1 &&
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optionsDisjunctionOptimizable(options) {
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rv, err := optimizeCompositeSearcher(ctx, "disjunction:unadorned",
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indexReader, qsearchers, options)
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if err != nil || rv != nil {
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return rv, err
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}
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}
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}
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if len(qsearchers) > DisjunctionHeapTakeover {
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return newDisjunctionHeapSearcher(ctx, indexReader, qsearchers, min, options,
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limit)
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}
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return newDisjunctionSliceSearcher(ctx, indexReader, qsearchers, min, options,
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limit)
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}
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func optimizeCompositeSearcher(ctx context.Context, optimizationKind string,
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indexReader index.IndexReader, qsearchers []search.Searcher,
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options search.SearcherOptions) (search.Searcher, error) {
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var octx index.OptimizableContext
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for _, searcher := range qsearchers {
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o, ok := searcher.(index.Optimizable)
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if !ok {
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return nil, nil
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}
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var err error
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octx, err = o.Optimize(optimizationKind, octx)
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if err != nil {
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return nil, err
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}
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if octx == nil {
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return nil, nil
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}
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}
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optimized, err := octx.Finish()
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if err != nil || optimized == nil {
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return nil, err
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}
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tfr, ok := optimized.(index.TermFieldReader)
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if !ok {
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return nil, nil
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}
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return newTermSearcherFromReader(ctx, indexReader, tfr,
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[]byte(optimizationKind), "*", 1.0, options)
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}
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func tooManyClauses(count int) bool {
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if DisjunctionMaxClauseCount != 0 && count > DisjunctionMaxClauseCount {
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return true
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}
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return false
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}
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func tooManyClausesErr(field string, count int) error {
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return fmt.Errorf("TooManyClauses over field: `%s` [%d > maxClauseCount,"+
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" which is set to %d]", field, count, DisjunctionMaxClauseCount)
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}
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