Function decodeArrayToArrow

pgserver/logrepl/decode.go:307–585

decodeArrayToArrow decodes Postgres array data and appends directly to Arrow builder

(typeMap *pgtype.Map, ac *pgtype.ArrayCodec, data []byte, format int16, scale int32, builder *array.ListBuilder)

// decodeArrayToArrow decodes Postgres array data and appends directly to Arrow builder
func decodeArrayToArrow(typeMap *pgtype.Map, ac *pgtype.ArrayCodec, data []byte, format int16, scale int32, builder *array.ListBuilder) (int, error) {
	if data == nil {
		builder.AppendNull()
		return 0, nil
	}

	// This must be called before (NOT after!) appending elements to the value builder
	builder.Append(true)

	var (
		et     = ac.ElementType
		oid    = et.OID
		values = builder.ValueBuilder()
	)

	// StringBuilder.Append is just StringBuilder.BinaryBuilder.Append
	if b, ok := values.(*array.StringBuilder); ok {
		values = b.BinaryBuilder
	}

	// Heap allocations are unavoidable if we stick to ArrayCodec,
	// but it should not be a bottleneck here.
	switch oid {
	case pgtype.BoolOID:
		if values, ok := values.(*array.BooleanBuilder); ok {
			var v pgtype.FlatArray[pgtype.Bool]
			if err := ac.PlanScan(typeMap, oid, format, &v).Scan(data, &v); err != nil {
				return 0, err
			}
			for _, e := range v {
				if e.Valid {
					values.Append(e.Bool)
				} else {
					values.AppendNull()
				}
			}
			return len(v) * 1, nil
		}

	case pgtype.Int2OID:
		if values, ok := values.(*array.Int16Builder); ok {
			var v pgtype.FlatArray[pgtype.Int2]
			if err := ac.PlanScan(typeMap, oid, format, &v).Scan(data, &v); err != nil {
				return 0, err
			}
			for _, e := range v {
				if e.Valid {
					values.Append(e.Int16)
				} else {
					values.AppendNull()
				}
			}
			return len(v) * 2, nil
		}

	case pgtype.Int4OID:
		if values, ok := values.(*array.Int32Builder); ok {
			var v pgtype.FlatArray[pgtype.Int4]