Function createEventIterators

tempodb/encoding/vparquet5/block_traceql_fetch.go:744–860

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

}

func createEventIterators(
	makeIter, makeNilIter makeIterFn,
	conditions []traceql.Condition,
	allConditions bool,
	dedicatedColumns backend.DedicatedColumns,
	selectAll bool,
) (required, optional []parquetquery.Iterator, err error) {
	// TODO - Preserving compatibility with original fetch.
	// If there are no event-level conditions we do nothing.
	// Which means we are ignoring event data during select all.
	if len(conditions) == 0 {
		return nil, nil, nil
	}

	var (
		columnSelectAs    = map[string]string{}
		columnPredicates  = map[string][]parquetquery.Predicate{}
		genericConditions []traceql.Condition
		columnMapping     = dedicatedColumnsToColumnMapping(dedicatedColumns, backend.DedicatedColumnScopeEvent)
	)

	addPredicate := func(columnPath string, p parquetquery.Predicate) {
		columnPredicates[columnPath] = append(columnPredicates[columnPath], p)
	}

	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
		}
	}

	for _, cond := range conditions {
		switch cond.Attribute.Intrinsic {
		case traceql.IntrinsicEventName:
			pred, err := createStringPredicate(cond.Op, cond.Operands)
			if err != nil {
				return nil, nil, err
			}
			optional = append(optional, makeIter(ColumnPathEventName, pred, ColumnPathEventName))
			continue
		case traceql.IntrinsicEventTimeSinceStart:
			pred, err := createIntPredicate(cond.Op, cond.Operands)
			if err != nil {
				return nil, nil, err
			}