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bleve/search/facet/facet_builder_datetime.go
Marty Schoch 0eba2a3f0c reduce garbage created while processing facets
previously we parsed/returned large sections of the documents
back index row in order to compute facet information.  this
would require parsing the protobuf of the entire back index row.
unfortunately this creates considerable garbage.

this new version introduces a visitor/callback approach to
working with data inside the back index row.  the benefit
of this approach is that we can let the higher-level code
see values, prior to any copies of data being made or
intermediate garbage being created.  implementations of
the callback must copy any value which they would like to
retain beyond the callback.

NOTE: this approach is duplicates code from the
automatically generated protobuf code

NOTE: this approach assumes that the "field" field be serialized
before the "terms" field.  This is guaranteed by our currently
generated protobuf encoder, and is recommended by the protobuf
spec.  But, decoders SHOULD support them occuring in any order,
which we do not.
2017-03-02 17:00:46 -05:00

135 lines
3.1 KiB
Go

// Copyright (c) 2014 Couchbase, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package facet
import (
"sort"
"time"
"github.com/blevesearch/bleve/numeric"
"github.com/blevesearch/bleve/search"
)
type dateTimeRange struct {
start time.Time
end time.Time
}
type DateTimeFacetBuilder struct {
size int
field string
termsCount map[string]int
total int
missing int
ranges map[string]*dateTimeRange
sawValue bool
}
func NewDateTimeFacetBuilder(field string, size int) *DateTimeFacetBuilder {
return &DateTimeFacetBuilder{
size: size,
field: field,
termsCount: make(map[string]int),
ranges: make(map[string]*dateTimeRange, 0),
}
}
func (fb *DateTimeFacetBuilder) AddRange(name string, start, end time.Time) {
r := dateTimeRange{
start: start,
end: end,
}
fb.ranges[name] = &r
}
func (fb *DateTimeFacetBuilder) Field() string {
return fb.field
}
func (fb *DateTimeFacetBuilder) UpdateVisitor(field string, term []byte) {
if field == fb.field {
fb.sawValue = true
// only consider the values which are shifted 0
prefixCoded := numeric.PrefixCoded(term)
shift, err := prefixCoded.Shift()
if err == nil && shift == 0 {
i64, err := prefixCoded.Int64()
if err == nil {
t := time.Unix(0, i64)
// look at each of the ranges for a match
for rangeName, r := range fb.ranges {
if (r.start.IsZero() || t.After(r.start) || t.Equal(r.start)) && (r.end.IsZero() || t.Before(r.end)) {
fb.termsCount[rangeName] = fb.termsCount[rangeName] + 1
fb.total++
}
}
}
}
}
}
func (fb *DateTimeFacetBuilder) StartDoc() {
fb.sawValue = false
}
func (fb *DateTimeFacetBuilder) EndDoc() {
if !fb.sawValue {
fb.missing++
}
}
func (fb *DateTimeFacetBuilder) Result() *search.FacetResult {
rv := search.FacetResult{
Field: fb.field,
Total: fb.total,
Missing: fb.missing,
}
rv.DateRanges = make([]*search.DateRangeFacet, 0, len(fb.termsCount))
for term, count := range fb.termsCount {
dateRange := fb.ranges[term]
tf := &search.DateRangeFacet{
Name: term,
Count: count,
}
if !dateRange.start.IsZero() {
start := dateRange.start.Format(time.RFC3339Nano)
tf.Start = &start
}
if !dateRange.end.IsZero() {
end := dateRange.end.Format(time.RFC3339Nano)
tf.End = &end
}
rv.DateRanges = append(rv.DateRanges, tf)
}
sort.Sort(rv.DateRanges)
// we now have the list of the top N facets
if fb.size < len(rv.DateRanges) {
rv.DateRanges = rv.DateRanges[:fb.size]
}
notOther := 0
for _, nr := range rv.DateRanges {
notOther += nr.Count
}
rv.Other = fb.total - notOther
return &rv
}