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# Resolving "Cannot Append Data in Parquet Format" error in ClickHouse

> Are you getting the error "Cannot append data in format Parquet to file" error in ClickHouse? Let's take a look at how to resolve it.

{frontMatter.description}

<h2 id="resolving-cannot-append-data-in-parquet-format-error-in-clickhouse">
  Resolving "Cannot Append Data in Parquet Format" Error in ClickHouse
</h2>

Are you getting the error "Cannot append data in format Parquet to file" error in ClickHouse?

Typically the error is reported as:

`DB::Exception: Cannot append data in format Parquet to file, because this format doesn't support appends. (CANNOT_APPEND_TO_FILE)`

Suppose you create a table that uses the `File` table engine with the Parquet format.

```sql theme={null}
CREATE TABLE parquet_test
(
    `x` UInt32,
    `y` String
)
ENGINE = File(Parquet)
```

You can write to the table once:

```sql theme={null}
INSERT INTO parquet_test VALUES
   (1, 'Hello'),
   (2, 'Hi')
```

This creates a file named `data.Parquet` in the `data/default/parquet_test` folder. If you try to insert another batch:

```sql theme={null}
INSERT INTO parquet_test VALUES
   (3, 'World'),
   (4, 'Bye')
```

...you get the following error:

```response theme={null}
Code: 641. DB::Exception: Received from localhost:9000. DB::Exception: Cannot append data in format Parquet to file, because this format doesn't support appends. You can allow to create a new file on each insert by enabling setting engine_file_allow_create_multiple_files. (CANNOT_APPEND_TO_FILE)
```

You can not append to Parquet files in ClickHouse. But you can tell ClickHouse to create a new file for every `INSERT` by enabling the [`engine_file_allow_create_multiple_files` setting](/reference/settings/session-settings#engine_file_allow_create_multiple_files). If enabled, on each insert a new file will be created with a name following this pattern:

`data.Parquet` -> `data.1.Parquet` -> `data.2.Parquet`, etc.:

Let's give it a try. We will put our two commands into a single file named `parquet.sql`:

```sql theme={null}
SET engine_file_allow_create_multiple_files = 1;

INSERT INTO default.parquet_test VALUES  (3, 'World'), (4, 'Bye');
```

Run it using `clickhouse-client`:

```bash theme={null}
./clickhouse client --queries-file parquet.sql
```

And now you will see two files in `data/default/parquet_test` (and a new file for each subsequent insert).

<Note>
  The `engine_file_allow_create_multiple_files` setting applies to other data formats that are not appendable, like JSON and ORC.
</Note>