{"record":{"id":"a1fef42a4b6c656d","repo":"pathwaycom/pathway","slug":"failed-to-find-the-column-column-name-in-tabl","errorCode":null,"errorMessage":"Failed to find the column '{column._name}' in table {column._table}","messagePattern":"Failed to find the column '(.+?)' in table (.+?)","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"python/pathway/io/_synchronization.py","lineNumber":274,"sourceCode":"        else:\n            column = synchronized_column.column\n            priority = synchronized_column.priority\n            idle_duration = synchronized_column.idle_duration\n            if idle_duration is not None:\n                idle_duration = datetime.timedelta(\n                    seconds=as_duration_seconds(idle_duration, \"idle_duration\")\n                )\n\n        column_types.add(column._column.dtype)\n        _check_column_type(column, max_difference)\n\n        column_idx = None\n        for index, field in enumerate(column._table._schema.column_names()):\n            if field == column._name:\n                column_idx = index\n                break\n        if column_idx is None:\n            raise ValueError(\n                f\"Failed to find the column '{column._name}' in table {column._table}\"\n            )\n\n        is_table_found = False\n        for node in G._current_scope.nodes:\n            if (\n                not isinstance(node, InputOperator)\n                or not isinstance(node.datasource, GenericDataSource)\n                or node.outputs[0].value != column._table\n            ):\n                continue\n            is_table_found = True\n            group = api.ConnectorGroupDescriptor(\n                name, column_idx, max_difference, priority, idle_duration\n            )\n            if node.datasource.data_source_options.synchronization_group is not None:\n                raise ValueError(\n                    \"Only one column from a table can be used in a synchronization group\"","sourceCodeStart":256,"sourceCodeEnd":292,"githubUrl":"https://github.com/pathwaycom/pathway/blob/fa2f74a4649b7c5908690cf60137263d8d80de5f/python/pathway/io/_synchronization.py#L256-L292","documentation":"ValueError raised when a ColumnReference used in a synchronization group has a name that is not found among the schema column names of its table. The code scans column._table._schema.column_names(); if the referenced column's name is absent, the reference cannot be mapped to a connector field index.","triggerScenarios":"Passing a column reference whose name was renamed (t.rename_columns(ts='time') then using the old reference), a column from a table whose schema was redefined, or a reference created before with_columns replaced the table. The loop over schema column_names finds no field == column._name.","commonSituations":"Renaming columns before calling the sync API; using a reference captured from the original table after with_columns/rename created a new table; typos in column names passed as references from helper functions.","solutions":["Use a column reference from the final table: sync(t_renamed.ts, other.time, ...) where t_renamed = t.rename_columns(ts='time')","Rebuild references after schema-changing transformations instead of reusing stale ones","Print table.schema to confirm the column names available on the table you pass"],"exampleFix":"// before\nt2 = t.rename_columns(ts='time')\npw.io.synchronize(t.time, other.time, max_difference=600)  # t.time stale\n\n// after\nt2 = t.rename_columns(ts='time')\npw.io.synchronize(t2.time, other.time, max_difference=600)","handlingStrategy":"validation","validationCode":"def column_in_table_schema(col_ref, table) -> bool:\n    return col_ref._name in list(table._schema.column_names())","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Derive column references from the table actually passed to sync()","Re-create references after with_columns/rename_columns","Assert reference names against table.schema in tests"],"tags":["pathway","io","synchronization","schema","columns"],"backgroundTag":null,"analyzedSha":"fa2f74a4649b7c5908690cf60137263d8d80de5f","analyzedAt":"2026-08-15T01:48:17.006Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}