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iterator.go
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iterator.go
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package reindexer
import (
"context"
"encoding/json"
"fmt"
"reflect"
"strings"
"github.com/restream/reindexer/bindings"
)
// ExplainResults presents query plan
type ExplainResults struct {
// Total query execution time
TotalUs int `json:"total_us"`
// Query prepare and optimize time
PrepareUs int `json:"prepare_us"`
// Indexes keys selection time
IndexesUs int `json:"indexes_us"`
// Query post process time
PostprocessUS int `json:"postprocess_us"`
// Intersection loop time
LoopUs int `json:"loop_us"`
// Index, which used for sort results
SortIndex string `json:"sort_index"`
// Filter selectos, used to proccess query conditions
Selectors []struct {
// Field or index name
Field string `json:"field"`
// Method, used to process condition
Method string `json:"method"`
// Number of uniq keys, processed by this selector (may be incorrect, in case of internal query optimization/caching
Keys int `json:"keys"`
// Count of comparators used, for this selector
Comparators int `json:"comparators"`
// Cost expectation of this selector
Cost float32 `json:"cost"`
// Count of processed documents, matched this selector
Matched int `json:"matched"`
// Count of scanned documents by this selector
Items int `json:"items"`
} `json:"selectors"`
}
func errIterator(err error) *Iterator {
return &Iterator{err: err}
}
func errJSONIterator(err error) *JSONIterator {
return &JSONIterator{err: err}
}
func newIterator(
userCtx context.Context,
q *Query,
result bindings.RawBuffer,
nsArray []nsArrayEntry,
joinToFields []string,
joinHandlers []JoinHandler,
queryContext interface{},
) (it *Iterator) {
if q != nil {
it = &q.iterator
it.query = q
} else {
it = &Iterator{}
}
it.nsArray = nsArray
it.joinToFields = joinToFields
it.joinHandlers = joinHandlers
it.queryContext = queryContext
it.resPtr = 0
it.ptr = 0
it.err = nil
it.userCtx = userCtx
if len(it.joinToFields) > 0 {
it.current.joinObj = make([][]interface{}, len(it.joinToFields))
}
it.setBuffer(result)
return
}
func newJSONIterator(ctx context.Context, q *Query, json []byte, jsonOffsets []int, explain []byte) *JSONIterator {
var ji *JSONIterator
if q != nil {
ji = &q.jsonIterator
} else {
ji = &JSONIterator{}
}
ji.json = json
ji.jsonOffsets = jsonOffsets
ji.ptr = -1
ji.query = q
ji.explain = explain
ji.err = nil
ji.userCtx = ctx
return ji
}
// Iterator presents query results
type Iterator struct {
ser resultSerializer
rawQueryParams rawResultQueryParams
result bindings.RawBuffer
nsArray []nsArrayEntry
joinToFields []string
joinHandlers []JoinHandler
queryContext interface{}
query *Query
allowUnsafe bool
resPtr int
ptr int
current struct {
obj interface{}
joinObj [][]interface{}
rank int
}
err error
userCtx context.Context
}
func (it *Iterator) setBuffer(result bindings.RawBuffer) {
it.ser = newSerializer(result.GetBuf())
it.result = result
it.rawQueryParams = it.ser.readRawQueryParams(func(nsid int) {
it.nsArray[nsid].localCjsonState = it.nsArray[nsid].cjsonState.ReadPayloadType(&it.ser.Serializer)
})
}
// Next moves iterator pointer to the next element.
// Returns bool, that indicates the availability of the next elements.
func (it *Iterator) Next() (hasNext bool) {
if it.ptr >= it.rawQueryParams.qcount || it.err != nil {
return
}
if it.needMore() {
it.fetchResults()
}
it.current.obj, it.current.rank = it.readItem()
if it.err != nil {
return
}
it.resPtr++
it.ptr++
return it.ptr <= it.rawQueryParams.qcount
}
func (it *Iterator) joinedNsIndexOffset(parentNsID int) int {
if it.query == nil {
return 1
}
offset := 1 + len(it.query.mergedQueries)
for m := 0; m < parentNsID; m++ {
offset += len(it.query.mergedQueries[m].joinQueries)
}
return offset
}
func (it *Iterator) readItem() (item interface{}, rank int) {
params := it.ser.readRawtItemParams()
if (it.rawQueryParams.flags & bindings.ResultsWithPercents) != 0 {
rank = params.proc
}
subNSRes := 0
if (it.rawQueryParams.flags & bindings.ResultsWithJoined) != 0 {
subNSRes = int(it.ser.GetVarUInt())
}
item, it.err = unpackItem(&it.nsArray[params.nsid], ¶ms, it.allowUnsafe && (subNSRes == 0), (it.rawQueryParams.flags&bindings.ResultsWithItemID) == 0, nil)
if it.err != nil {
return
}
nsIndexOffset := it.joinedNsIndexOffset(params.nsid)
for nsIndex := 0; nsIndex < subNSRes; nsIndex++ {
siRes := int(it.ser.GetVarUInt())
if siRes == 0 {
continue
}
subitems := make([]interface{}, siRes)
for i := 0; i < siRes; i++ {
subparams := it.ser.readRawtItemParams()
subitems[i], it.err = unpackItem(&it.nsArray[nsIndex+nsIndexOffset], &subparams, it.allowUnsafe, (it.rawQueryParams.flags&bindings.ResultsWithItemID) == 0, nil)
if it.err != nil {
return
}
}
it.current.joinObj[nsIndex] = subitems
it.join(nsIndex, nsIndexOffset, params.nsid, item)
}
return
}
func (it *Iterator) needMore() bool {
if it.resPtr >= it.rawQueryParams.count && it.ptr <= it.rawQueryParams.qcount {
return true
}
return false
}
func (it *Iterator) fetchResults() {
if fetchMore, ok := it.result.(bindings.FetchMore); ok {
fetchCount := defaultFetchCount
if it.query != nil {
fetchCount = it.query.fetchCount
}
if it.err = fetchMore.Fetch(it.userCtx, it.ptr, fetchCount, false); it.err != nil {
return
}
it.resPtr = 0
it.setBuffer(it.result)
} else {
panic(fmt.Errorf("unexpected behavior: have the partial query but binding not support that"))
}
return
}
func (it *Iterator) join(nsIndex, nsIndexOffset, parentNsID int, item interface{}) {
field := it.joinToFields[nsIndex]
subitems := it.current.joinObj[nsIndex]
handler := it.joinHandlers[nsIndex]
if handler != nil {
if !handler(field, item, subitems) {
return
}
}
if joinable, ok := item.(Joinable); ok {
joinable.Join(field, subitems, it.queryContext)
} else {
v := getJoinedField(reflect.ValueOf(item), it.nsArray[parentNsID].joined, field)
if !v.IsValid() {
panic(fmt.Errorf("Can't find field with tag '%s' in struct '%s' for put join results from '%s'",
field,
it.nsArray[0].rtype,
it.nsArray[nsIndex+nsIndexOffset].name))
}
if v.IsNil() {
v.Set(reflect.MakeSlice(reflect.SliceOf(reflect.PtrTo(it.nsArray[nsIndex+nsIndexOffset].rtype)), 0, len(subitems)))
}
for _, subitem := range subitems {
v.Set(reflect.Append(v, reflect.ValueOf(subitem)))
}
}
}
// Object returns current object.
// Will panic when pointer was not moved, Next() must be called before.
func (it *Iterator) Object() interface{} {
if it.resPtr == 0 {
panic(errIteratorNotReady)
}
return it.current.obj
}
// Rank returns current object search rank.
// Will panic when pointer was not moved, Next() must be called before.
func (it *Iterator) Rank() int {
if it.resPtr == 0 {
panic(errIteratorNotReady)
}
return it.current.rank
}
// JoinedObjects returns objects slice, that result of join for the given field
func (it *Iterator) JoinedObjects(field string) (objects []interface{}, err error) {
if it.resPtr == 0 {
return nil, errIteratorNotReady
}
idx := it.findJoinFieldIndex(field)
if idx == -1 {
return nil, errJoinUnexpectedField
}
return it.current.joinObj[idx], nil
}
// Count returns count if query results
func (it *Iterator) Count() int {
return it.rawQueryParams.qcount
}
// TotalCount returns total count of objects (ignoring conditions of limit and offset)
func (it *Iterator) TotalCount() int {
return it.rawQueryParams.totalcount
}
// AllowUnsafe takes bool, that enable or disable unsafe behavior.
//
// When AllowUnsafe is true and object cache is enabled resulting objects will not be copied for each query.
// That means possible race conditions. But it's good speedup, without overhead for copying.
//
// By default reindexer guarantees that every object its safe to use in multithread.
func (it *Iterator) AllowUnsafe(allow bool) *Iterator {
it.allowUnsafe = allow
return it
}
// FetchAll returns all query results as slice []interface{} and closes the iterator.
func (it *Iterator) FetchAll() (items []interface{}, err error) {
defer it.Close()
if !it.Next() {
return nil, it.err
}
items = make([]interface{}, it.rawQueryParams.qcount)
for i := range items {
items[i] = it.Object()
if !it.Next() {
break
}
}
return
}
// FetchOne returns first element and closes the iterator.
// When it's impossible (count is 0) err will be ErrNotFound.
func (it *Iterator) FetchOne() (item interface{}, err error) {
defer it.Close()
if it.Next() {
return it.Object(), it.err
}
if it.err == nil {
it.err = ErrNotFound
}
return nil, it.err
}
// FetchAllWithRank returns resulting slice of objects and slice of objects ranks.
// Closes iterator after use.
func (it *Iterator) FetchAllWithRank() (items []interface{}, ranks []int, err error) {
defer it.Close()
if !it.Next() {
return nil, nil, it.err
}
items = make([]interface{}, it.rawQueryParams.qcount)
ranks = make([]int, it.rawQueryParams.qcount)
for i := range items {
items[i] = it.Object()
ranks[i] = it.Rank()
if !it.Next() {
break
}
}
if it.err != nil {
return nil, nil, err
}
return
}
// HasRank indicates if this iterator has info about search ranks.
func (it *Iterator) HasRank() bool {
return (it.rawQueryParams.flags & bindings.ResultsWithPercents) != 0
}
// AggResults returns aggregation results (if present)
func (it *Iterator) AggResults() (v []AggregationResult) {
l := len(it.rawQueryParams.aggResults)
v = make([]AggregationResult, l)
for i := 0; i < l; i++ {
json.Unmarshal(it.rawQueryParams.aggResults[i], &v[i])
}
return
}
// GetAggreatedValue - Return aggregation sum of field
func (it *Iterator) GetAggreatedValue(idx int) float64 {
if idx < 0 || idx >= len(it.rawQueryParams.aggResults) {
return 0
}
res := AggregationResult{}
json.Unmarshal(it.rawQueryParams.aggResults[idx], &res)
return res.Value
}
// GetExplainResults returns JSON bytes with explain results
func (it *Iterator) GetExplainResults() (*ExplainResults, error) {
if len(it.rawQueryParams.explainResults) > 0 {
explain := &ExplainResults{}
if err := json.Unmarshal(it.rawQueryParams.explainResults, explain); err != nil {
return nil, fmt.Errorf("Explain query results is broken")
}
return explain, nil
}
return nil, nil
}
// Error returns query error if it's present.
func (it *Iterator) Error() error {
return it.err
}
// Close closes the iterator and freed CGO resources
func (it *Iterator) Close() {
if it.result != nil {
it.result.Free()
it.result = nil
if it.query != nil {
it.query.close()
}
}
return
}
func (it *Iterator) findJoinFieldIndex(field string) (index int) {
for index = range it.joinToFields {
if strings.EqualFold(it.joinToFields[index], field) {
return
}
}
return -1
}
// JSONIterator its iterator, but results presents as json documents
type JSONIterator struct {
json []byte
jsonOffsets []int
query *Query
err error
ptr int
explain []byte
userCtx context.Context
}
// Next moves iterator pointer to the next element.
// Returns bool, that indicates the availability of the next elements.
func (it *JSONIterator) Next() bool {
it.ptr++
return it.ptr < len(it.jsonOffsets)
}
// FetchAll returns bytes slice it's JSON array with results
func (it *JSONIterator) FetchAll() (json []byte, err error) {
defer it.Close()
return it.json, it.err
}
// JSON returns JSON bytes with current document
func (it *JSONIterator) JSON() (json []byte) {
if it.ptr < 0 {
panic(errIteratorNotReady)
}
o := it.jsonOffsets[it.ptr]
l := 0
if it.ptr+1 < len(it.jsonOffsets) {
l = it.jsonOffsets[it.ptr+1] - 1
} else {
l = len(it.json) - 2
}
return it.json[o:l]
}
// GetExplainResults returns JSON bytes with explain results
func (it *JSONIterator) GetExplainResults() (*ExplainResults, error) {
if len(it.explain) > 0 {
explain := &ExplainResults{}
if err := json.Unmarshal(it.explain, explain); err != nil {
return nil, fmt.Errorf("Explain query results is broken")
}
return explain, nil
}
return nil, nil
}
// Count returns count if query results
func (it *JSONIterator) Count() int {
return len(it.jsonOffsets)
}
// Error returns query error if it's present.
func (it *JSONIterator) Error() error {
return it.err
}
// Close closes the iterator.
func (it *JSONIterator) Close() {
if it.query != nil {
it.query.close()
it.query = nil
}
}