func Filter(query *parser.SelectQuery, series *protocol.Series) (*protocol.Series, error) {
if query.GetWhereCondition() == nil {
return series, nil
}
columns := map[string]struct{}{}
if query.GetFromClause().Type == parser.FromClauseInnerJoin {
outer:
for t, cs := range query.GetResultColumns() {
for _, c := range cs {
// if this is a wildcard select, then drop all columns and
// just use '*'
if c == "*" {
columns = make(map[string]struct{}, 1)
columns[c] = struct{}{}
break outer
}
columns[t.Name+"."+c] = struct{}{}
}
}
} else {
for _, cs := range query.GetResultColumns() {
for _, c := range cs {
columns[c] = struct{}{}
}
}
}
points := series.Points
series.Points = nil
for _, point := range points {
ok, err := matches(query.GetWhereCondition(), series.Fields, point)
if err != nil {
return nil, err
}
if ok {
filterColumns(columns, series.Fields, point)
series.Points = append(series.Points, point)
}
}
if _, ok := columns["*"]; !ok {
newFields := []string{}
for _, f := range series.Fields {
if _, ok := columns[f]; !ok {
continue
}
newFields = append(newFields, f)
}
series.Fields = newFields
}
return series, nil
}
func NewQueryEngine(query *parser.SelectQuery, responseChan chan *protocol.Response) (*QueryEngine, error) {
limit := query.Limit
queryEngine := &QueryEngine{
query: query,
where: query.GetWhereCondition(),
limiter: NewLimiter(limit),
responseChan: responseChan,
seriesToPoints: make(map[string]*protocol.Series),
// stats stuff
explain: query.IsExplainQuery(),
runStartTime: 0,
runEndTime: 0,
pointsRead: 0,
pointsWritten: 0,
shardId: 0,
shardLocal: false, //that really doesn't matter if it is not EXPLAIN query
duration: nil,
seriesStates: make(map[string]*SeriesState),
}
if queryEngine.explain {
queryEngine.runStartTime = float64(time.Now().UnixNano()) / float64(time.Millisecond)
}
yield := func(series *protocol.Series) error {
var response *protocol.Response
queryEngine.limiter.calculateLimitAndSlicePoints(series)
if len(series.Points) == 0 {
return nil
}
if queryEngine.explain {
//TODO: We may not have to send points, just count them
queryEngine.pointsWritten += int64(len(series.Points))
}
response = &protocol.Response{Type: &queryResponse, Series: series}
responseChan <- response
return nil
}
var err error
if query.HasAggregates() {
err = queryEngine.executeCountQueryWithGroupBy(query, yield)
} else if containsArithmeticOperators(query) {
err = queryEngine.executeArithmeticQuery(query, yield)
} else {
err = queryEngine.distributeQuery(query, yield)
}
if err != nil {
return nil, err
}
return queryEngine, nil
}
func NewFilteringEngine(query *parser.SelectQuery, processor Processor) *FilteringEngine {
shouldFilter := query.GetWhereCondition() != nil
return &FilteringEngine{query, processor, shouldFilter}
}