Function createSpanIterators

tempodb/encoding/vparquet5/block_traceql_fetch.go:422–742

(
	makeIter, makeNilIter makeIterFn,
	needDriver bool,
	conditions []traceql.Condition,
	allConditions bool,
	selectAll bool,
	dedicatedColumns backend.DedicatedColumns,
	sampler traceql.Sampler,
)

}

func createSpanIterators(
	makeIter, makeNilIter makeIterFn,
	needDriver bool,
	conditions []traceql.Condition,
	allConditions bool,
	selectAll bool,
	dedicatedColumns backend.DedicatedColumns,
	sampler traceql.Sampler,
) (driver parquetquery.Iterator, required, optional []parquetquery.Iterator, err error) {
	var (
		columnSelectAs    = map[string]string{}
		columnPredicates  = map[string][]parquetquery.Predicate{}
		genericConditions []traceql.Condition
		columnMapping     = dedicatedColumnsToColumnMapping(dedicatedColumns, backend.DedicatedColumnScopeSpan)
	)

	// todo: improve these methods. if addPredicate gets a nil predicate shouldn't it just wipe out the existing predicates instead of appending?
	// nil predicate matches everything. what's the point of also evaluating a "real" predicate?
	addPredicate := func(columnPath string, p parquetquery.Predicate) {
		columnPredicates[columnPath] = append(columnPredicates[columnPath], p)
	}

	addNilPredicateIfNotAlready := func(path string) {
		preds := columnPredicates[path]
		foundOpNone := false

		// check to see if there is a nil predicate and only add if it doesn't exist
		for _, pred := range preds {
			if pred == nil {
				foundOpNone = true
				break
			}
		}

		if !foundOpNone {
			addPredicate(path, nil)
			columnSelectAs[path] = path
		}
	}

	specialCase := func(cond traceql.Condition, columnPath string) (handled bool) {
		// Operands that need special handling.
		switch cond.Op {
		case traceql.OpNone:
			addPredicate(columnPath, nil) // No filtering
			columnSelectAs[columnPath] = cond.Attribute.Name
			return true
		case traceql.OpExists:
			addPredicate(columnPath, &parquetquery.SkipNilsPredicate{})
			columnSelectAs[columnPath] = cond.Attribute.Name
			return true
		case traceql.OpNotExists:
			optional = append(optional, makeIter(columnPath, parquetquery.NewNilValuePredicate(), cond.Attribute.Name))
			return true
		default:
			return false
		}
	}