522f9d5cc7
this introduces disk format v4 now the summary rows for a term are stored in their own "dictionary row" format, previously the same information was stored in special term frequency rows this now allows us to easily iterate all the terms for a field in sorted order (useful for many other fuzzy data structures) at the top-level of bleve you can now browse terms within a field using the following api on the Index interface: FieldDict(field string) (index.FieldDict, error) FieldDictRange(field string, startTerm []byte, endTerm []byte) (index.FieldDict, error) FieldDictPrefix(field string, termPrefix []byte) (index.FieldDict, error) fixes #127
87 lines
2.1 KiB
Go
87 lines
2.1 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
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// except in compliance with the License. You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed under the
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// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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package upside_down
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import (
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"bytes"
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"fmt"
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"github.com/blevesearch/bleve/index"
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"github.com/blevesearch/bleve/index/store"
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)
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type UpsideDownCouchFieldDict struct {
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indexReader *IndexReader
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iterator store.KVIterator
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endKey []byte
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field uint16
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}
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func newUpsideDownCouchFieldDict(indexReader *IndexReader, field uint16, startTerm, endTerm []byte) (*UpsideDownCouchFieldDict, error) {
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startKey := NewDictionaryRow(startTerm, field, 0).Key()
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if endTerm == nil {
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endTerm = []byte{ByteSeparator}
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}
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endKey := NewDictionaryRow(endTerm, field, 0).Key()
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it := indexReader.kvreader.Iterator(startKey)
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return &UpsideDownCouchFieldDict{
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indexReader: indexReader,
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iterator: it,
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field: field,
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endKey: endKey,
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}, nil
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}
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func (r *UpsideDownCouchFieldDict) Next() (*index.DictEntry, error) {
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key, val, valid := r.iterator.Current()
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if !valid {
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return nil, nil
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}
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// past end term
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if bytes.Compare(key, r.endKey) > 0 {
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return nil, nil
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}
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currRow, err := NewDictionaryRowKV(key, val)
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if err != nil {
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return nil, fmt.Errorf("unexpected error parsing dictionary row kv: %v", err)
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}
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rv := index.DictEntry{
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Term: string(currRow.term),
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Count: currRow.count,
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}
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// advance the iterator to the next term
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r.iterator.Next()
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return &rv, nil
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}
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func (r *UpsideDownCouchFieldDict) Close() error {
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return r.iterator.Close()
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}
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func incrementBytes(in []byte) []byte {
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rv := make([]byte, len(in))
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copy(rv, in)
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for i := len(rv) - 1; i >= 0; i-- {
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rv[i] = rv[i] + 1
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if rv[i] != 0 {
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// didn't overflow, so stop
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break
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}
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}
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return rv
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}
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