pathwaycom/pathway · error · ValueError

All synchronization group column types must coincide. Howeve

Error message

All synchronization group column types must coincide. However several types have been detected: {}

What it means

Error "All synchronization group column types must coincide. However several types have been detected: {}" thrown in pathwaycom/pathway.

Source

Thrown at python/pathway/io/_synchronization.py:303

                continue
            is_table_found = True
            group = api.ConnectorGroupDescriptor(
                name, column_idx, max_difference, priority, idle_duration
            )
            if node.datasource.data_source_options.synchronization_group is not None:
                raise ValueError(
                    "Only one column from a table can be used in a synchronization group"
                )
            node.datasource.data_source_options.set_synchronization_group(group)
            break

        if not is_table_found:
            raise ValueError(
                "Only unchanged columns of an input tables can be used in input synchronization groups"
            )

    if len(column_types) > 1:
        raise ValueError(
            "All synchronization group column types must coincide. "
            "However several types have been detected: {}".format(
                ", ".join(sorted([f"'{t}'" for t in column_types]))
            )
        )


def _check_column_type(column, max_difference):
    column_type = column._column.dtype
    if column_type not in _SUPPORTED_COLUMN_DTYPES:
        raise ValueError(
            f"Fields of type {column_type.typehint} are not supported in connector groups"
        )
    if isinstance(max_difference, int) and column_type != dtype.INT:
        raise ValueError(
            "If max_difference is an integer value, the values of a column must have a type of "
            f"int. However, the column '{column}' has type '{column_type.typehint}'"
        )

View on GitHub (pinned to fa2f74a464)

Solutions

1. Cast all columns in the synchronization group to a single common type before registering the group, so every column type coincides.

Example fix

t = t.select(t1=pw.declare_type(pw.DateTimeUtc, t.t1), t2=pw.declare_type(pw.DateTimeUtc, t.t2))

When it happens

Trigger: Thrown at python/pathway/io/_synchronization.py:303 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of pathwaycom/pathway@fa2f74a464 (2026-08-15). Data as JSON: /api/errors/5d6a2e377a4f2f07. Report an issue: GitHub.